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Earthmoving OperationsContents

Page

PREFACE .................................................................................................................. v

Chapter 1

MANAGING EARTHMOVING OPERATIONS ............... ................. ................. ...... 1-1

Project Management ............................................................................................... 1-1Equipment Selection ............................................................................................... 1-1Production Estimates .............................................................................................. 1-1Material Considerations .......................................................................................... 1-2Zones Of Operation ................................................................................................ 1-6

Chapter 2

DOZERS ............... ................. ................. ................. ................. ................. ............. 2-1Description .............................................................................................................. 2-1Blades ..................................................................................................................... 2-2Clearing and Grubbing Operations ......................................................................... 2-3

Sidehill Excavations ................................................................................................ 2-9Operation Techniques ........................................................................................... 2-11Dozer Production Estimates ................................................................................. 2-18Ripping Production Estimates ............................................................................... 2-23Safety Precautions ................................................................................................ 2-26

Chapter 3

SCRAPERS ................. .................. ................. ................. .................. ................. .... 3-1Description .............................................................................................................. 3-1Production Cycle ..................................................................................................... 3-2Production Estimates .............................................................................................. 3-9

DISTRIBUTION RESTRICTION: Approved for public release; distribution is unlimited.

*This publication supersedes FM 5-434, 26 August 1994, and FM 5-164, 30 August 1974.

Field Manual * FM 5-434No. 5-434 Headquarters

Department of the ArmyWashington, DC 15 JUNE 2000


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FM 5-434

ii

Page

Chapter 4 GRADERS ............................................................................................................. 4-1Grader Components ............................................................................................... 4-1

Road and Ditch Construction ................................................................................. 4-2

Earth- and Gravel-Road Maintenance ................................................................... 4-8

Snow Removal ..................................................................................................... 4-10

Asphalt Mixing ...................................................................................................... 4-10

Operation Techniques and Tips ........................................................................... 4-11

Production Estimates ........................................................................................... 4-14

Safety ................................................................................................................... 4-15

Chapter 5 LOADERS .............................................................................................................. 5-1Description ............................................................................................................. 5-1

Attachments ........................................................................................................... 5-1

Use ......................................................................................................................... 5-3Selection ................................................................................................................ 5-3

Operation ............................................................................................................... 5-3

Production Estimates ............................................................................................. 5-8

Safety ................................................................................................................... 5-10

Chapter 6 FORKLIFTS ........................................................................................................... 6-1Use ......................................................................................................................... 6-1

Operation Techniques ............................................................................................ 6-1

Safety ..................................................................................................................... 6-2

Chapter 7 CRANES ................................................................................................................ 7-1Basic Crane Unit .................................................................................................... 7-1

Hoisting Operations ................................................................................................ 7-7

Pile Driver ............................................................................................................. 7-11

Clamshell ............................................................................................................. 7-12

Dragline ................................................................................................................ 7-15

Safety ................................................................................................................... 7-20

Chapter 8 HYDRAULIC EXCAVATORS ................................................................................ 8-1Description ............................................................................................................. 8-1

Excavation Techniques .......................................................................................... 8-2Operation Techniques ............................................................................................ 8-3

Small Emplacement Excavator with a Loader Bucket ............................................ 8-4

Track-Mounted Excavator ...................................................................................... 8-8

Production Estimates ............................................................................................. 8-8


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FM 5-434

iii

Page

Chapter 9 AIR COMPRESSORS AND PNEUMATIC TOOLS ............................................... 9-1Air Compressors .................................................................................................... 9-1

Compressed-Air Uses ............................................................................................ 9-4

Air Manifolds .......................................................................................................... 9-5

Pneumatic Tools .................................................................................................... 9-6

Safety ................................................................................................................... 9-17

Chapter 10 HAULING EQUIPMENT ...................................................................................... 10-1Dump Trucks ........................................................................................................ 10-1

Equipment Trailers ............................................................................................... 10-6

Chapter 11 SOIL-PROCESSING AND COMPACTION ......................................................... 11-1Soil Processing .................................................................................................... 11-1

Soil Compaction ................................................................................................... 11-7

Chapter 12 ROAD SURFACING ............................................................................................ 12-1Surface Treatment ............................................................................................... 12-1

Surfacing Equipment ............................................................................................ 12-1

In-Place Mixing Equipment .................................................................................. 12-8

Bitumen Handling and Dedrumming Equipment .................................................. 12-9

Support Equipment ............................................................................................ 12-10

Chapter 13 SAFETY ............................................................................................................... 13-1Safety Program .................................................................................................... 13-1

General Safety Rules ........................................................................................... 13-1

Operator Indoctrination ........................................................................................ 13-2

Operator Qualifications and Requirements .......................................................... 13-2

Equipment Inspection ........................................................................................... 13-2

Repairs and Maintenance .................................................................................... 13-2

Guards and Safety Devices ................................................................................. 13-3

Signals ................................................................................................................. 13-3

Ropes, Cables, and Chains ................................................................................. 13-3

Equipment Loading .............................................................................................. 13-6

Equipment Transporting ....................................................................................... 13-7

Night Operations .................................................................................................. 13-7Excavations .......................................................................................................... 13-7

Chapter 14 ENVIRONMENTAL PROTECTION ..................................................................... 14-1Preoperations Checklist ....................................................................................... 14-1

Personnel-Preparation Checklist .......................................................................... 14-2


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v

PrefaceThis field manual (FM) is a guide for engineer personnel responsible for planning,designing, and constructing earthworks in the theater of operations. It gives estimatedproduction rates, characteristics, operation techniques, and soil considerations foreart hm oving equipment . This guide should be used to help select t he most economicalan d effective equipmen t for each individual operat ion.

This ma nu al discusses th e complete pr ocess of estima ting equipmen t pr oduction rat es.However, users of this manual are encouraged to use their experience and data fromother projects in estima ting production ra tes.

The material in this manual applies to all construction equipment regardless of makeor model. The equipment used in this manual are examples only. Information for pro-duction calculations should be obtained from the operator and maintenance manualsfor t he ma ke an d model of the equipment being used.

Append ix A cont ains an E nglish-to-metr ic mea sur ement conversion chart .

The pr oponen t of this publication is HQ TRADOC. Send comm ents an d recommenda-tions on Depart ment of th e Army (DA) Form 2028 directly to United Sta tes Army E ngi-neer School (USAES), ATTN: ATSE-DOT-DD, Directorate of Training, 320 EngineerLoop Su ite 336, Fort Leona rd Wood, Missour i 65473-8929.

Unless this publication states otherwise, masculine nouns and pronouns do not referexclus ively to men .


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Managing Earthmoving Operations 1-1

Chapter 1Managing Earthmoving Operations

E ar th m o v in g m ay in c lu d e s i t e p rep a ra t io n ; ex cav a t io n ; em b an k m en tcons tr uction; backfil l ing; dredging; prepar ing bas e cour se, subba se, an dsubgra de; compa ction; and r oad s ur facing. The types of equipment us edand th e environm ent al con ditions will affect t he ma n- and m achine-hour srequired t o complete a given a mount of work . Before prepar ing estima tes,choose th e bes t met hod o f operat ion an d th e type of equ ipment to use .E a ch p iece o f eq u ip m en t i s sp ec i fi ca l ly d es ig n ed to p e r fo rm ce r t a inmechan ical ta sks . Therefore , base th e equ ipm ent se lect ion on efficien t

operat ion a nd a vailability.

P ROJECT MANAGEMENT1-1. Project m ana gers mus t fol low bas ic man agement phases t o ensu re th atc on s t r u c t i on p r oj e ct s s u c ce s s f u l l y m e e t d e a d l i n e s s e t f o r t h i n p r o je c td irect ives . Addi t ional ly, managers mus t ensure conformance to safety ande n v i r on m e n t a l - p r ot e ct i on s t a n d a r d s . T h e b a s i c m a n a g e m e n t p h a s e s a sdiscussed in FM 5-412 are

P la nn ing. Or ga n izing. Sta ffin g. Dir ect in g. Con t rolling. E xecu t in g.

EQUIPMENT SELECTION1-2. Pr oper equipmen t selection is crucial to achieving efficient ear th movingan d const ru ction operat ions. Consider th e ma chines operat iona l capa bilit iesan d equipment a vai labi li ty when select ing a ma chine for a par t icular t ask .The ma na ger should v isual ize how bes t to employ th e avai lable equipmentb a s e d o n s o i l c on s i d e r a t i o n s , z o n e o f o p e r a t i o n , a n d p r o je c t - s p e c i fi crequiremen ts. Equipmen t pr oduction-estimat ing procedur es discussed in t his

man ua l help quan tify equipment pr oductivity.

P RODUCTION ESTIMATES1-3. Production estimat es, production cont rol, and pr oduction records a re th ebas is for m an agemen t d ecis ions . Ther efore , it i s h elpful t o have a commonmet hod of recording, directin g, and r eportin g production. (Refer t o specific,


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FM 5-434

1-2 Managing Earthmoving Operations

equipment pr oduct ion-es t imat ing procedures in t he app ropr ia te chapters inth is manu al .)

PROD UCTION-RATE FORMULA

1-4. The most convenient an d useful un it of work done an d un it of t ime to use

in calculat ing productivity for a par ticular piece of equipment or a p ar ticular job is a fun ction of the sp ecific work-task being a na lyzed. To mak e accurat ean d mea ningful compar isons a nd conclus ions a bout product ion , i t i s bes t touse s tanda rdized terms .

P roduc t ion r a te . The ent ire expression is a t ime-related pr oductionra te . I t can be cubic yar ds per h our, tons per sh ift (a lso indicat e thedur ation of the sh ift) , or feet of ditch per h our .

U n i t o f w ork done . This denotes the unit of productionaccomplished. I t can be th e volume or weight of th e mat erial moved,th e num ber o f p ieces o f ma t e r i a l cu t , the d i s t a nce t r a ve led , or a nysimilar measu remen t of production.

U n i t o f t ime . This denotes an arbi t rar y t ime uni t such as a minut e ,an hour, a 10-hour shift , a day, or a ny other convenient du ra t ion inwhich th e un it of work done is accomplish ed.

TIME-REQUIRED FORMULA

1-5. The inverse of the product ion-rate formula is sometimes useful whenschedul ing a pr oject becaus e i t def ines t he t ime requir ed to accomplish anarbitr ar y amount of work.

NOTE: Express the t ime required in uni ts s uch as hours pe r 1 ,000 cubicyards , hours pe r acre , days per acre , or minut es pe r foot of d i tch .

MATERIAL CONSID ERATIONS1-6. Depending on where a mat erial is considered in th e const ru ction process,du r ing excava t ion ve r s us a f t e r compac t ion , th e s am e ma te r i a l w e igh t w i lloccupy d ifferent volum es (Figure 1-1). Mater ia l volume can be mea sur ed inone of three st ates:

Bank cubic yard (BCY). A BCY is 1 cubic yard of mat erial a s it liesin i ts natur al /undis turbed s ta te .

Loose c ubic yard (LCY). A LCY is 1 cubic yard of material after ithas been distur bed by an excavation pr ocess.

Compacted cubic yard (CCY). A CCY is 1 cubic yard of materialafter compaction.

Production rate unit of work doneunit of time--------------------------------------------------=

Time required unit of timeunit of work done--------------------------------------------------=


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FM 5-434


Figure 1-1. Material-Volume Changes Caused by Construction Processes

1-7. When manipulating the material in the construction process, i ts volumechanges. (Tables 1-1 a n d 1-2, page 1-4, give mat erial-volum e conver sion a ndload factors . ) The pr ime question for an eart hmover is about th e na tur e of th ema te r i a l s ph ys ica l p r oper t i e s ; for exam ple , how eas y i s i t t o move? F orea r t hm oving opera t ions , ma te r i a l i s p laced in th ree ca t egor ies rock , s oi l(common earth), and unclassified.

Rock . Rock is a material that ordinary earthmoving equipmentcannot r emove. Fra ctur ing r ock r equires dr i l l ing a nd blas t ing . Afterblasting, use excavat ors to load t he r ock fra gments in to hau l un its forremoval.

Soi l . Soils ar e classified by par ticle-size distribut ion a nd cohesiveness.

For ins tan ce, gravel and sa nds h ave b locky-shaped pa r t ic les an d ar en o n c oh e s i v e , wh i l e c la y h a s s m a l l , p l a t y - s h a p e d p a r t i c l es a n d i scohes ive . Al though r ipp ing equ ipm en t ma y be n eces s a ry to loosenconsolidate d deposits, soil removal does not requ ire u sing explosives.

U nc las s i f i ed . The unclassified (rock-soil) combination is the mostcommon m at erial foun d th roughout t he world. I t is a m ixture of rock and soil mat erials .

SOIL PROPERTIES

1 -8 . I n a n e a r t h m o v in g o p e r a t i o n , t h o r ou g h l y a n a l y z e t h e m a t e r i a l ' sp r o p e r t i e s ( l oa d a b i li t y , m o is t u r e c o n t e n t , p e r c e n t a g e o f s w el l, a n dcompactabi l ity) an d incorporate th is inform at ion in t o the cons tr uct ion p lan .Soil prepara tion a nd compaction requiremen ts a re discussed in Chapter 11.

Loadabi l i ty

1 -9 . L oa d a b i li t y i s a g e n e r a l m a t e r i a l p r o p e r t y o r c h a r a c t e r i s t i c . I f t h ema ter ia l is easy to d ig an d load, i t ha s h igh loadabi l i ty. Conversely, i f th ema ter ial is difficult to dig an d load, it ha s low loadability. Certa in t ypes of clayand loam ar e easy to doze or load int o a scraper from their na tu ral s t ate.

1.25 cubic yards afterdigging (LCY)

1 cubic yard in naturalconditions (BCY)

0.9 cubic yards aftercompaction (CCY)


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FM 5-434


M ois tu re Con ten t

1-10. Moistu re cont ent is a very import an t factor in eart hm oving work s incemois tur e affects a so i l s u ni t weight an d h an dl ing proper t ies . All so il in i tsn a t u r a l s t a t e co n t a i n s s o m e m o i s t u r e . T h e a m o u n t o f m o is t u r e r e t a i n e ddepends on th e w ea th e r, the d ra ina ge , an d th e s o il s r e t en t ion p roper t i e s .M e ch a n i ca l o r c h e m i ca l t r e a t m e n t c a n s o m e t i m e s ch a n g e t h e m o i s t u r econtent of a soil . Refer to Chap ter 11 for informat ion about increas ing anddecreasin g the soils moistu re cont ent .

Table 1-1. Material Volume Conversion Factors

Converted ToMaterial Type Converted From Bank (In Place) Loose Compacted

Sand or gravel Bank (in place)LooseCompacted

0.901.05

1.11 1.17

0.950.86

Loam(common earth) Bank (in place)LooseCompacted

0.801.11

1.25 1.39

0.900.72

Clay Bank (in place)LooseCompacted

0.701.11

1.43 1.59

0.900.63

Rock (blasted) Bank (in place)LooseCompacted

0.670.77

1.50 1.15

1.300.87

Coral(comparableto lime rock)

Bank (in place)LooseCompacted

0.670.77

1.50 1.15

1.300.87

Table 1-2. Material Weight, Swell Percentages, and Load Factors

Material Type

Loose(Pounds PerCubic Yards)

Swell(Percent) Load Factor

Bank(Pounds PerCubic Yard)

CindersClay, dryClay, wetEarth (loam or silt), dryEarth (loam or silt), wetGravel, dryGravel, wetSand, drySand, wetShale (soft rock)

Trap rock

800 to 1,2001,700 to 2,0002,400 to 3,0001,900 to 2,2002,800 to 3,2002,700 to 3,0002,800 to 3,1002,600 to 2,9002,800 to 3,1002,400 to 2,700

2,700 to 3,500

40 to 554040

15 to 3525

10 to 1510 to 1510 to 1510 to 15

65

50

0.65 to 0.720.720.72

0.74 to 0.870.80

0.87 to 0.910.87 to 0.910.87 to 0.910.87 to 0.91

0.60

0.66

1,100 to 1,8602,360 to 2,7803,360 to 4,2002,180 to 2,9803,500 to 4,0002,980 to 3,4503,080 to 3,5602,860 to 3,3403,080 to 3,5604,000 to 4,500

4,100 to 5,300NOTE: The above numbers are averages for common materials. Weights and loadfactors vary with such factors as grain size, moisture content, and degree ofcompaction. If an exact weight for a specific material must be determined, run a teston a sample of that particular material.


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FM 5-434


P ercen tage o f S w el l

1-11. Most ear th and r ock ma ter ia ls swell when removed from th eir n atu ra lr e s t i n g p l a c e . T h e v o lu m e e x p a n d s b e c a u s e o f v o id s c r e a t e d d u r i n g t h eexcavat ion process . Af ter es tabl ish ing the general c lass i f icat ion of a so i l ,es t imat e th e percentage of swel l. Express swel l as a percenta ge increase involume ( Ta ble 1-2 ) . For example, the swell of dry clay is 40 percent, whichmean s th at 1 cubic yard of clay in t he ba nk s ta te will fi l l a sp ace of 1.4 cubicyards in a loosened sta te. Est imate t he swell of a soil by referrin g to a t able of mat erial properties such as T able 1-2.

Compactabi l i ty

1-12. In ear th moving work, i t is comm on to compact soil to a higher densit ytha n it was in its na tu ral s ta te. This is becau se there is a corr elation betweenhigher density and increased str ength, redu ced settlement , improved bearingcapaci ty, and lower permeabi l i ty. The project specif icat ions wil l s ta te thedensity requirements.

SOIL WEIGHT1-13. Soil weight affects the performance of the equipment. To estimate theequipment r equirements of a job accura te ly, th e uni t weight of th e ma ter ia lbeing moved must be kn own. Soil weight affects h ow dozers pu sh , gra derscast , and scraper s load th e mat erial. Assume th at t he volumet ric capa city of as cr a p e r i s 2 5 cu b i c ya r d s a n d t h a t i t h a s a r a t e d l oa d c a p a c i t y of 5 0 , 00 0poun ds . I f the mat er ia l being carr ied is re la t ively l ight (such a s c inder) , theload will exceed th e volum etr ic capa ci ty of th e scra per before r eaching t hegra vimetr ic capacity. Conver sely, if the load is gra vel (which ma y weigh m orethan 3 ,000 pounds per cubic yard) , i t wi l l exceed the gravimetr ic capaci tybefore reaching th e volum etr ic capacity. See Table 1-2 for the u nit weight of specific ma ter ials.

NOTE: The same mater ia l weight wil l occupy different volumes inBCY, LCY, and CCY. In an earthmoving operation, the basic unit of compar ison is usual ly BCY. Also , cons ider the mater ia l in i ts looses ta te ( the volume of the load) . Tab le 1-1 gives average mater ia l conver-s ion factors for ear th-volume c hange s .

LOAD FACTOR

1-14. Use a load factor (see T able 1-2) to convert t he volum e of LCY mea su redt o B C Y m e a s u r e d ( ). U s e s i m i l a r f a c t o r s w h e nconverting ma terial to a compacted stat e. The factors depen d on th e degree of compaction. Compu te t he load factor a s follows:

In t his case, th e load factor for dr y clay is 0.72. This m eans th at if a scra per iscarr ying 25 LCY of dr y clay, it is carr ying 18 BCY (25 x 0.72) .

LCY load factor BCY=

If 1 cubic yard of clay (bank state) 1.4 cubic yards of clay (loose state),then 1 cubic yard of clay (loose state) 11. 4-------- or 0.72 cubic yard of clay (bank state).=

=


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FM 5-434


ZONES OF OPERATION1-15 . The r e la t ions h ip o f s pec i fi c zones o f opera t ion t o va r ious t ypes o f eart hm oving equipment is s ignificant when selecting ear thm oving equipment.A ma ss diagram grap hically depicts h ow ma teria ls should be moved an d is agood tool for deter minin g the zones of operat ion. Mass diagr am s ar e explainedi n F M 5 -4 3 0 -0 0 - 1. T h e r e a r e t h r e e z on e s o f op e r a t i on t o co n s i d er o n aconstruction project.

POWER ZONE

1-16. In the power zone, maximum power is required to overcome adverse siteor job conditions. Such conditions include rough terrain, steep slopes, pioneerop e r a t i o n s , or e x t r e m e l y h e a v y lo a d s . Th e w o r k i n t h e s e a r e a s r e q u i r e scrawler t r actors that can develop h igh dra wbar pul l a t s low speeds . In t heseadverse conditions, the more t raction a tr actor develops, the more likely it willreach its full potential.

SLOW-SPEED HAULING ZONE

1-17. The slow-speed h au ling zone is s im ilar t o the power zone since power,more th an speed, is th e essent ia l factor. S i te condi t ions ar e s l ight ly bet t ert h a n i n t h e p o w e r z on e , a n d t h e h a u l d i s t a n c e i s s h o r t . S in c e im p r o ve dcondi t ions g ive the dozer more power, and dis tan ces ar e too shor t for m os tscrapers t o bui ld up su fficient momen tu m t o shif t in to h igher speeds , bothmach ines a ch ieve the s am e s peed . Cons ide ra t ions th a t de t e rmine a s low -speed h au ling zone a re a s follows:

The ground cond i t ions do no t pe rmit r ap id t r avel and the movemen tdista nce of th e mat eria l is beyond economical dozing operat ions.

The hau l di st ances a r e not long enough to pe rmit s cr aper s to t r ave l a thigh speeds.

HIGH-SP EED HAULING ZONE1-18. In th e h igh-speed hau l ing zone, cons tru ct ion h as pr ogressed to whereground condi t ions a re good, or where long, wel l-maint ained ha ul roads ar eesta blished. Achieve this condit ion a s soon a s possible. Production increasesw h e n t h e s c r a p e r i s w or k i n g a t i t s m a x i m u m s p e e d . C on s i d e r a t i o n s t h a tdetermin e a high-speed ha uling zone a re a s follows:

Good haul ing condi t ions exis t on both grade and haul-road surfaces . H au l d is t ances a r e long enough to pe rmit acce le ra t ion to max imum

tra vel speeds. P us h t r ac tor s (a l s o r e fe r r ed to a s pus her s ) a r e ava il able to a s si st in

loading.

CAUTIONOperate equipment at safe speeds to prevent personalinjury or premature failure of the machines majorcomponents. Accomplish hauling operations safely as wellas efficiently.


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Dozers 2-1

Chapter 2Dozers

Dozers (tra cklaying crawlers or wheel tra ctors equ ipped with a blade) arep e r h a p s t h e m os t b a s i c a n d v e r s a t i l e i t e m s o f e q u i p m e n t i n t h econst ruction indust ry. Dozers ar e designed t o provide high dr awbar pulland t r ac t ion effo r t . They are th e s tan dard equ ipment for land c lear ing ,dozing, an d assist ing in scraper loading. They can be equipped with rea r-mounted winches or r ippers. Crawler tractors exert low ground-bearingpressu re, which adds to th eir versat ility. For long m oves between projectsor with in a pr oject, tr an sport dozers on hea vy tr ailers. Moving them u nd er

their own power, even a t slow speeds, increases tr ack wear an d shorten sth e machin es operat iona l life.

DESCRIPTION2-1 . A cra w le r dozer cons i s t s o f a pow er p lan t (typ ica l ly a d ies e l eng ine )mounted on an un dercarr iage, which r ides on t ra cks . The t r acks extend th efull length of th e dozer. Ther e ar e two classificat ions of milita ry dozers, basedon weight an d pounds of dr awbar pull. The light class (about 16,000 poundsop e r a t i n g w e i gh t ) i n cl u d e s t h e d e p l oy a b l e u n i v e r s a l c o m b a t e a r t h m o ve r(DEUCE) (Figure 2-1) . The medium class includes dozers h aving an operat ingweight of 15,000 t o 45,000 poun ds (Figure 2-2, p age 2-2).

Figure 2-1. DEUCE, Light-Class Dozer


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FM 5-434

2-2 Dozers

Figure 2-2. Medium-Class Dozer

BLADES2-2. A dozer blade consists of a moldboa rd with repla ceable cutt ing edges an ds ide bi t s . E i the r th e pus h a rm s and t i l t cy linder s o r a C- fr a me a r e u s ed toconn ect t he b lade to th e t r a c tor. B lades va ry in s i ze and d es ign bas ed onspecific work ap plications. Th e h arden ed-steel cutt ing edges an d side bits ar ebolted on becau se th ey receive most of the abr asion and wear out ra pidly. Thisallows for eas y replacemen t. Machine design s allow either ed ge of the blade tobe ra ised or lowered in th e ver t ical p lane of the b lade ( t i l t ) . The t op of theblade can be pitched forward or backward varying the angle of attack of thecut t ing edge (p i tch) . Blades moun ted on a C-fra me can be tu rn ed from th edirection of travel (angling). These features are not applicable to all blades,but a ny two of these featu res ma y be incorporat ed in a s ingle mount.

STRAIGHT BLADE

2-3. Use straight blades for push ing mat erial an d cut ting ditches. This bladeis mount ed in a fixed pos i t ion , perpen dicular to th e l ine of t r avel . I t can bet i l ted an d pi tched ei ther forwar d or backwar d with in a 10 ar c . Ti l t ing the

blade a llows concent ra tion of dozer dr iving power on a limited lengt h of theblade. P i tching th e b lade provides increased penet ra t ion for cut t ing or lesspenetra tion for back dragging.

ANGLE BLADE

2-4. Angle blades, which are 1 to 2 feet wider than straight blades, are usedmost effectively to side cast m at eria l when backfilling or when m akin g sidehillcuts . Use an an gle b lade for r ough gradin g, spreading pi les , or windr owing


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m a t e r i a l . I t c a n b e a n g l ed u p t o a m a x im u m of 2 5 l e ft o r r i g h t o f perpendicular to the dozer or used as a s t raight blade. When an gled, th e bladecan be til ted but i t cann ot be pitched.

SPECIAL-PURPOSE BLADE

2-5. There are special blades (Figure 2 -3), such as t he Rome K/G, designed forclea r ing b ru s h a nd t r ees bu t n o t fo r ea r th mov ing . The Rome K /G b lade i spe rma nen t ly fixed a t an an g le . O n one end o f the b lad e i s a s t inger. Th i ss t inger cons is ts of a ver t ical sp l i t ter and s t i ffener and a t r iangular-shapedh o r i zo n t a l p a r t c a l le d t h e w eb . On e s i d e o f t h e t r i a n g u l a r w e b a b u t s t h ebottom of th e vertical splitter, an d th e other s ide abut s th e cutt ing edge of th eblade. The abut ting sides of the web are ea ch a bout 2 feet in length, dependingon how far th e stinger pr otrudes from the blade. This blade is designed t o cutdown b ru s h a nd t r ees a t , or a few inches a bove , g round l eve l r a t he r t ha nuproot ing them . When cut t ing a large-diameter t ree , fi r s t us e the s t inger t os p l it t he t r ee to weaken i t ; t h en , cu t the t r ee of f and pus h i t ove r w i th t heblade. Keep both the st inger and t he cuttin g edge shar p. The operator mu st bewell-train ed to be efficient in th is opera tion. There a re other special-purposeblades not discussed in th is manu al which can be moun ted on dozers.

Figure 2-3. Special-Purpose Clearing Blade

CLEARING AND GRUB BING OP ERATIONS2-6. Clear ing vegetat ion and t rees is usual ly necessary before moving andshap ing the groun d. Clear ing includes removing su rface boulders a nd oth ermat erials embedded in t he ground an d th en disposing of th e cleared ma terial.Ens u re tha t env ironmen ta l -p ro tect ion cons ide ra t ions a r e add r es s ed be forecondu c t ing c lea r in g opera t ions . S pec i fi ca t ions ma y a l low s hea r ing o f th evegetat ion a nd t rees at ground level, or i t m ay be necessary to grub (removing

Web

Cuttingedge

Guide bar

Stinger

Splitting point


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stu mps a nd roots from below th e groun d). Pr oject specificat ions will dicta teth e proper clearing t echn iques. Plan clear ing operations to allow disposal of deb r i s in one ha nd l ing . I t i s bes t t o t r a ve l in one d i r ect ion w hen c lea r ing .Changing direct ion tends to sk in and scrape the t rees ins tead of uproot ingt h e m or a l lo wi n g a c l ea n c u t . C l ea r i n g t e c h n i q u e s v a r y w it h t h e t y p e o f

vege ta t ion be ing clea r ed , th e g roun ds s o i l type , an d th e s o il s mo is tu recondition. Ta ble 2-1 shows average c lear ing ra tes for normal area-clear ing

jobs. Increase the T able 2-1 values by 60 percent if the pr oject requires s tr ip-type clearing (common in tactical land clearing). Engineers perform tacticall a n d c le a r i n g a s a c om b a t s u p p o r t f u n ct i on i n t e n d e d t o e n h a n c e a n dcomplement mobility, firepower, surveillance, and target acquisition.

BRUS H AND SMALL TREES

2-7. Moving th e dozer, with th e blade slight ly below groun d level, will usua llyremove small tr ees and bru sh. The blade cuts , brea ks off , or uproots most of the t ree and bends the r es t for r emoval on t he re t urn t r ip . A medium tr actorwith a d ozer blade can clear an d pile about 0.25 acres of brush or small tr eesper hour.

MEDIUM TREES

2-8. To remove a medium -size t ree (7 to 12 inches in dia meter) , raise t he bladeas h igh a s possible to gain a dded leverage an d th en pu sh t he t ree over s lowly.As th e tr ee star ts t o fall , back th e dozer quickly to avoid th e ris ing roots . Thenlower th e blade an d drive th e dozer forwar d, l ift ing out t he roots . The averagetime for a medium tra ctor with a dozer blade to clear an d pile medium trees is2 to 9 minut es per tree.

LARGE TREES

2-9. Removing large t r ees (12 to 30 inches in d iam eter) is mu ch s lower a ndm o r e d i ffi cu l t t h a n c le a r i n g b r u s h a n d s m a l l e r t r e e s . F i r s t , g e n t l y a n dcautiously probe the t ree for dea d limbs th at could fall . Determ ine th e tre esnat ur al direction of lean, if an y; th is is the best direction for pu shing th e treeover. Then , pos i t ion t he b lade h igh a nd cen te r i t on th e t r ee for m ax imum

Table 2-1. Quick Production Estimates for Normal Area Clearing

Equipment

Equipment (Hours Per Acre)

Light(12 Inches or Less*)

Medium(12 to 18 Inches*)

Heavy(18 Inches*)

Bulldozer:Medium tractorHeavy tractor

2.51.5

5.03.0

10.08.0

Shear blade:Medium tractorHeavy tractor

0.40.3

0.80.5

1.30.8

*Maximum tree size

NOTE: These clearing rates are average for tree counts of 50 trees per acre. Adverseconditions (slopes, rocks, soft ground) can reduce these rates significantly.


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leverage. If possible, push t he tr ee over t he sa me a s a medium tree. However,i f the t ree has a mass ive, deeply embedded root sys tem, use the fo l lowingmethod (Figure 2 -4):

Figure 2-4. Four Steps for Removing a Large Tree With a Massive,Deeply Embedded Root System

S t e p 1 . Sta rt on th e side opposite th e proposed direction of fall, and mak e a cutdeep enough t o sever some of the lar ge roots. Make the cut like a V-ditch, tilteddownwar d latera lly toward t he roots.S t e p 2 . Cut side t wo.S t e p 3 . Cut side three.S t e p 4 . Build an earth ramp on the same side as the original cut to obtaingreater push ing leverage. Then push the t ree over and, as the t ree start s to fall ,reverse t he d ozer qu ickly to avoid t he rising r oot ma ss. After felling th e tr ee, fillth e stu mp h ole so tha t it will not collect water.

1. Cut roots on side one. 2. Cut side two.

3. Cut side three. 4. Build ramp on side one.Push tree over.Average clearing time:

5 to 20 minutes per tree


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The avera ge time for a medium tr actor with a dozer blade t o clear an d pile largetrees is 5 to 20 minutes per tree. The time required to clear and pile massivetrees requiring this four-step procedure will often be more than 20 minuteseach.

NOTE: The roots on the four th s ide m ay also nee d to be cu t .

ROOTS

2-10 . M oun t a r ake on t he dozer in p lace of the b lade t o r emove r oo t s an ds ma l l s tumps . A s the dozer moves forw ar d , i t fo rces th e t ee th o f th e r a kebelow th e ground s sur face. The teeth will catch t he belowgroun d roots andth e sur face brus h left f rom th e fe l l ing opera t ion , whi le the soi l remain s orpasses through.

SAFETY PRECAUTIONS

2-11. Never operat e clearin g tr actors t oo close togeth er. Do not follow a tr eetoo closely when push ing it , becau se when it begins to fall, i ts s tu mp a nd r ootsmay catch un der t he f ront of the dozer. Clean out accum ulated debr is in t he

dozer s belly pan often to prevent f ires in the engine compa rtm ent.

PR ODUCTION ESTIMATES

2-12. The two meth ods for es t imat ing product ion for c lear ing an d gru bbingprojects ar e the quick method and t he tr ee-coun t meth od.

Quick Method

2-13. Table 2-1, page 2-4, shows quick estima tes for n ormal ar ea clear ing. Usethe qu ick met hod only when a deta i led reconn aissan ce an d a t ree coun t ar enot possible.

S t e p 1 . Determin e the size of the ar ea to clear (in acres).

S t e p 2 . Determin e the size and n um ber of dozers available.S t e p 3 . Determin e the ma ximum size of the tr ees to clear.S t e p 4 . Determine the time required (hours per acre) for clearing, based ondozer size and tr ee size (see Table 2-1).S t e p 5 . Determin e th e efficiency factor for t he work. Opera tors r equire brea ks,an d ther e are always secondary delays for min or equipmen t repa irs. Therefore,actual production time per hour is something less than 60 minutes. In the caseof a well-man aged job, expect 50 minu tes of production tim e per hour .

Acres to be cleared width (feet) length (feet)

43,560 square feet per acre-----------------------------------------------------------------------------=

Efficiency factor actual working minutes per hour60-minute working hour

--------------------------------------------------------------------------------------------=


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S t e p 6 . Determin e the operator factor using Ta ble 2-2 .S t e p 7 . Determin e the t otal t ime (in hour s) required to complete t he mission.

whereD = time required, in hours per acreA = total area, in acresE = efficiency factorO = operator factorN = number of dozers available

Table 2-2. Operator Factors for Track Dozers

Operator Ability Daylight Night

ExcellentAveragePoor

1.000.750.60

0.750.560.45

NOTE: These factors assume good visibility and a60-minute working hour efficiency.

Total time (hours) D AE O N-------------------------=

EXAMPLE

Determine the time required to clear an area that is 500-feet wide by 0.5 mile long. Twomedium bulldozers are available for the task. The largest trees in the area are 14 inchesin diameter, and the ground is fairly level. The operators are of average ability and will doall work during daylight hours. Expected efficiency is 50 minutes per hour.

Step 1.

Step 2. Dozer size = mediumNumber of dozers available = 2

Step 3. Maximum tree size = 14 inchesStep 4. Time required = 5 hours per acre (Table 2-1, page 2-4)

Step 5.

Step 6. Operator factor = 0.75 (Table 2-2)

Step 7.

Total area in acres width (feet) length (feet)43,560 square feet per acre-----------------------------------------------------------------------------=

500 feet 0.5 mile 5,280 feet per mile( )

43,560-----------------------------------------------------------------------------------------------------------------= 30.3 acres=

Efficiency factor 50 minutes per hour60-minute working hour-------------------------------------------------------------------- 0.83= =

Total time (hours) 5 hours per acre 30.3 acres0.83 0.75 2

---------------------------------------------------------------------------------- 121.6 or 122 hours= =


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Tree-Count Metho d

2-14. Use th is m ethod when a deta i led reconn aissan ce an d a t r ee count a repossible. The t ree-count meth od allows for a better production estimat e.

S t e p 1 . Determin e th e size of the a rea to clear (in a cres). Refer t o step 1 of the

quick met hod.S t e p 2 . Determin e the size and n um ber of dozers available.S t e p 3 . Determine the average number of each size of tree per acre. This willrequire a field reconn aissan ce.S t e p 4 . Determine the basic production factors (hours per acre) based on thedozer s ize an d t he size of th e tr ees to clear (Tab le 2-3).

S t e p 5 . Determin e the time requ ired to clear one acre.

where

D = clearing time of one acre, in minutes

H = hardwood factor affecting total time

H = 1.3 if hardwoods are 75 to 100 percentH = 1 if hardwoods are 25 to 75 percentH = 0.7 if hardwoods are 0 to 25 percent

A = tree-density and presence-of-vines factor affecting total time

A = 2 if density is more than 600 trees per acre (dense)A = 1 if density is 400 to 600 trees per acre (medium)A = 0.7 if density is less than 400 trees per acre (light)A = 2 if heavy vines are present

B = base time per acre determined from dozer size, in minutes

M = time required per tree in each diameter range, in minutes

N = number of trees per acre in each diameter range, from

reconnaissanceI = sum of diameter of all trees per acre greater than 6 feet in

diameter at ground level (in foot increments), from reconnaissance

F = time required per foot of diameter for trees greater than 6 feet indiameter, in minutes

NOTE: When i t i s necessary to grub roots and s tumps , increase thet ime pe r acre by 25 percent .

Table 2-3. Production Factors for Felling With a Clearing Blade

Tractor

Base MinutesPer Acre

B

Tree Diameter Range

1-2 FeetM1

2-3 FeetM2

3-4 FeetM3

4-6 FeetM4

More Than 6 FeetF

Medium 23.48 0.5 1.7 3.6 10.2 3.3

Heavy 18.22 0.2 1.3 2.2 6.0 1.8

NOTE: These times are based on working on reasonably level ground with good footing and anaverage mix of soft and hardwoods.

D H A B[ ] M1 N1[ ] M2 N2[ ] M3 N3[ ] M4 N4[ ] I F[ ]+ + + + +( )=


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S t e p 6 . Determin e the t otal t ime (in hour s) required to complete t he mission.

whereD = time required to clear one acre (from step 5), in hoursA = total areaN = number of dozers

NOTE: The t ree-count me thod h as no correct ion factor for eff ic iency oroperator sk i l l . The values in Ta ble 2-3 are based on normal eff ic iencyand average ope rator sk i l l.

SIDEHILL EXCAVATIONS2-15. One of a dozer s more imp or ta nt uses is m ak ing s idehi l l cuts , whichincludes pioneerin g road cut s a long h ills ides. An a ngle blade is pr eferred forth is opera tion because of its side-cas tin g ability.

CREATING A SLOP E

2-16. I t is best t o s ta rt t he cut a t th e top of th e hill , crea ting a bench severa ldozer lengths long. Do this by working up and down t he slope perpendicular toth e long direction of the p roject (Figure 2-5[A], page 2-10) . Design th e benchesto ensure t hat water r un s off without da maging th e slope. If possible, s ta rt t hebench on th e uphill extr eme of the cut ( the highest point of th e cut ) and th enwiden a nd deepen the cut un til the desired road profile is achieved. Be sure tostar t t he bench far enough u p th e slope to allow room for both t he inner s lopeand t he roadway.

NOTE: When w orking on extrem ely s teep s lopes , a winch l in e may benecess ary to s tabi l ize the dozer (see parag raph 2 -37 ) .

2-17. Becau se the p erpendicular pas ses ar e short, th e dozer us ually is not ableto develop a fu l l b lade load. Therefore , a fter cons t ru ct ing t he in i t ia l bench,tu rn th e dozer an d work in th e long direct ion of th e project (Figure 2-5[B],

page 2-10). D eve lop a fu l l b lade load an d the n tu rn th e dozer to pus h th ema ter ia l over th e s ide . Af ter developing th e bench, use e i ther a dozer or ascraper to complete the cut. Keep the inside (hills ide) of the roadway lowerth an th e outs ide. This a l lows th e dozer t o work effect ively on t he edge an ddecrea ses th e eros ion of the outer s lope. Mak e sure to main ta in th e properslope on th e inside of th e cut. I t is very difficult to chan ge th e cut s lope a fterconstr uction. Maint ain t he pr oper bench slope by moving out from th e insides lope on each s ucces s ive cu t . D e te rmine th e s lope r a t io f rom t he d i s t an cemoved awa y from t he s lope for each su ccessive cut an d th e depth of each cut.When cut t in g th e roads cross s lope, work f rom th e toe of th e bench t o theroads out side edge.

Total time (hours) D AN

--------------=


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Figure 2-5. Sidehill Cut

FINISHING A SIDE SLOPE

2-18. Ther e ar e two meth ods for finishin g a side slopework ing perp endicularto the slope an d working diagona lly up th e slope.

Work ing P erpend icu la r to the S lope

2-19. The dozer shown in Figure 2 -6 i s f in i s h ing a s ide s lope by w ork ingperpendicular to the slope. Sta rt t he dozer at t he top of th e embankm ent a nd,on each pass, earth will fall to the lower side of the blade forming a windrow.On su cceeding passes, pick u p th is windrow and u se it to f il l holes and other

i r r e g u l a r i t i e s in t h e t e r r a i n . B e ca r e fu l t o p r e v e n t t h e b l a d e cor n e r f r omdigging in too deep; th is would st eepen t he slope beyond job specificat ions .

Figure 2-6. Finishing a Side Slope Working Perpendicular to the Slope


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Working Diagon al ly Up the S lope

2-20. The dozer shown in Figure 2-7 is finishing t he side slope by star ting a tthe bot tom a nd working diagonal ly up the s lope. The windrow th at form s iscon t inu a l ly pus h ed to one s ide , w h ich t en ds to f il l low s po t s , h o les , an dirregu larit ies. This is one of th e few inst an ces where a dozer work s effectivelypush ing uph ill .

Figure 2-7. Finishing a Side Slope Working Diagonally up the Slope

OPERATION TECHNIQUES2-21. Dozers work best when th e ground is f irm a nd with out potholes, sh ar p

ridges, or r ocks. Uneven su rfaces ma ke it difficult t o keep the blad e in cont actwith th e ground. This tends to bury vegetat ion in hollows rat her t ha n r emovei t . To s ave t ime a nd inc rea s e ou t pu t , u s e th e fol low ing t echn iques w h enconditions permit.

DOZING

2-22. When s t ra ight dozing, if the b lade d igs in an d th e rear of the m achinerises, raise th e blade to continu e an even cut. If moving a h eavy load cau sesth e tra vel speed to drop, shift t o a lower gear a nd/or r aise th e blade slightly.When finishing or leveling, a full blade ha ndles easier tha n a part ially-loadedblade.

S ide -by-Side Dozi ng

2-23. S ide-by-s ide dozing wil l increase product ion 15 to 25 percent whenmoving mat erial 50 t o 300 feet (Figure 2-8, page 2-12). When th e d is ta nce isless th an 50 feet , the extra t ime needed to maneuver a nd pos it ion the dozerswill offset t he increa sed pr oduction.


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Figure 2-8. Side-by-Side Dozing

S lo t D oz ing

2-24. Slot dozing uses s pillage from t he first few pas ses to build a windr ow oneach side of a dozers pa th (Figure 2 -9). This forms a t rench, preventing blade-side spillage on subsequent passes. To increas e production, a lign cuts pa ra llel,leaving a nar row uncut section between slots . Then, r emove th e uncut sectionby norma l dozing. When grad e an d soil conditions a re favorable, s lot dozingcan in crease out put by as m uch as 20 percent.

Figure 2-9. Slot Dozing


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D ow nh i l l D oz ing

2-25 . P il e s evera l loads a t t he b r ink o f the h i l l, and t hen pus h them to thebottom in one pa ss. When dozing downh ill, tra vel to the bottom of th e hill withe a c h l o a d . U s e d o w n h i l l d o zi n g w h e n e v e r p o s s i b l e s i n c e it i n c r e a s e sproduction.

Hard-Mater ia ls Do zing

2 -2 6 . U s e t h e d o z e r b la d e t o lo os e n h a r d m a t e r i a l w h e n r i p p e r s a r e n o tavailable. Tilt t he blad e to force one corner into th e ma ter ial. Tilting is donethr ough blade cont rol, by driving one tr ack onto a r idge of ma terial bladed u pfor t his pu rpose or by placing a r ock or log under t he t ra ck. To maximize thedriving force of th e blade, hook only the t i l ted end u nder the mat erial. Break ath in layer by turning on i t wi th a dozer. Turning causes the t rack grousers(cleats) to break th rough t he top layer. With a t hin la yer of frozen m ater ial, itis best to break th rough at one point. By lifting an d push ing, the blade breaksthr ough the t op frozen layer a s shown in Figure 2-10.

Figure 2-10. Dozing Hard Materials or Frozen Ground Layers

Rock D oz ing

2-27. Use a ra ke to remove small rocks. The ra ke lets th e soil remain , or pa sst h r o u g h , w h i le d i g gi n g t h e r o ck s f r o m t h e e a r t h . W h e n r e m o vi n g l a rg e ,pa r t i a l ly bu r ied bou lde r s , t i lt t h e dozer b lade an d d ig th e ea r t h ou t f romar oun d th ree s ides of th e boulder. Lower th e b lade enough to get under th e

fou r th s ide . L if t the b la de as t he dozer moves fo rw ard to c r ea te a l if t ing ,ro l ling ac t ion o f th e bou lde r. I f the dozer cann o t pu s h t he bou lde r, l i ft i tupw ard w i th t he b lade a nd have s omeone p lace a log or s ome othe r ob jectu n d e r t h e b o u l d e r s o t h e d o z e r c a n g e t a n o t h e r h o ld . T h e r o l li n g a c t i onremoves th e boulder a s th e dozer moves forward. Dozer work in r ocky ar easincreas es tr ack wear . If possible, inst all rock shoes or r ock pa ds to cut down onthis wear.

F r o z e n t o p l a y e r


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2-14 Dozers

Wet-Mater ia ls Dozing

2-28. Wet ma ter ial is difficult to move with a dozer. Also, the wet gr ound m aybe too soft t o sup port t he weight of th e dozer. If so, mak e each su ccessive passth e full depth of th e wet ma ter ial. This will place th e dozer on a firm er footing.I f avai lable , use wider t ra cked shoes for bet ter f lota t ion . When workin g inmu d, push t he m ud back far enough t ha t i t wi l l not f low back in to the cut .Make provisions for recovery operations in case the dozer becomes stuck. Tryto use ma chines equipped with a winch.

DITCHING2-29. Shal low di tches ar e bes t a ccomplished us ing a grad er, but dozers canaccompl i s h rough d i t ch ing . Ti lt t he dozer b lade t o cu t s ha l low V-d it ches(Figure 2-11) . F o r l a rg e r d i t ch e s , p u s h t h e m a t e r i a l p e r p e n d i cu l a r t o t h ecent er l ine of the d i tch . After r eaching the des ired depth , pu sh t he ma ter ia lt h e l e n g t h o f t h e d i t ch t o s m o ot h t h e s i d e s a n d b o t t o m . M a n y t i m e s i t i snecessar y to correct irr egularities in a ditch. Attem pt to remove hum ps or f illholes in a s ingle pass. Use m ultiple passes to correct t he gra de.

Figure 2-11. Tilt Dozer Ditching

CONSTRUCTING A S TOCKPILE

2-30. A dozer is a good machine for creating stockpiles of material that canthen be eas i ly loaded in t o hau l un i t s by e ithe r a loader o r a hydra u l i c hoeexcava tor. Use t he following steps to constr uct a s tockpile:

S t e p 1 . Pu sh t he ma teria l from th e beginnin g of th e excavat ion to th e stockpilearea on the first pass. This distance should be no more than 75 feet from thestart point. Do not excavate deeper than 6 to 8 inches, while maintaining asmooth cut.

WARNINGBefore putting the machine in reverse, and whilebacking, the operator must be satisfied that no onewill be endangered.


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S tep 2 . Begin t o raise the bla de one dozer length from t he stockpile, lettin g thematerial drif t under the blade forming a ram p upon reaching the stockpile area.

S t e p 3 . Pu sh th e mat erial on su ccessive cuts in the sam e mann er, working thedozer from the start point all the way around the work area while stockpiling.Overlap cuts a bout one-th ird of the blades width to pick u p windrows.

NOTE: Do not s top the forward motion or cause the t racks to sp inw hi le pus h ing mate r i a l .

S t e p 4 . Make successive cuts the same as in step 2, constructing the stockpilehigher on each pass unt il it r eaches the desired height.

SP READING A STOCKPILE

2-31. Large piles should be worked from the side, cutting material away fromth e stockpile, usin g one-th ird of th e blade. Use th e following steps t o spr ead astockpile:

S t e p 1 . Lower th e blade to the desired height wh ile moving forward.S t e p 2 . Adjust the blade height and move the dozer into the side of the pilemak ing th e cut with only one-third of th e blade.

NOTE: When us ing the lef t s ide of the b lade, cont inue wo rking to thelef t . When us ing the r ight s ide of the b lade, cont inue working to theright.

S t e p 3 . Cut into th e stockpile. The blad e should be a s full as possible withoutstalling the dozer or spinning th e tracks. Raise and lower the blade to mainta ina smooth pass.

S t e p 4 . Spread th e blade load a fter cuttin g the p ile by cont inuing t o move for-

ward a nd slowly raising the blade un til all ma ter ial is evenly feat hered.S t e p 5 . Feather the blade load and reverse the dozer. Raise the blade about 12inches off the groun d, back th e dozer t o the st ockpile, and r eposition for a nothercut.Repeat th e above steps un til the stockpile has been leveled an d sprea d over thedesignated a rea. D o no t back blade t o level th e stockpile.

CAUTIONKeep the dozer under control at all times. Do not put the

transmission into neutral to allow the machine to coast.Select the gear range necessary before starting down thegrade. Do not change gears while going downhill.

WARNINGWhen spreading materials that are higher than themidpoint of the rollover protective structure (ROPS),adjust the height of the cut to eliminate the danger fromcollapsing material.


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2-16 Dozers

BACKFILLING

2-32. Backfilling can be effectively accomplished by drifting m at erial s idewayswith a n a ngle b lade. This a l lows forwar d m otion par al le l to the excavat ion .With a s t r a ight b lade, approach t he excavat ion a t a s l ight a ngle and then , a tt h e e n d o f t h e p a s s , t u r n i n t o w a r d t h e e x ca v a t i o n . N o p a r t of t h e t r a c k ss h o u l d h a n g o v er t h e e d g e . A d ju s t t h e l e n g t h o f t h e p u s h b a s e d o n s o i lcond i t ions . F or example , when w ork ing in s o ft m a t e r i a l o r on an un s ta b leslope, let t he second bladeful pu sh the firs t bladeful over th e edge. Be carefulto keep oversize mat erials out of the ba ckfill.

R IP P IN G

2-33. Figure 2-12 shows various ripping operat ions. Use firs t gear for r ippingopera tions. When performing one-shank ripping, always use th e center s han k.Use additional sha nk s, where pra ctical, to increa se production. When r ippingfor scra per loading, r ip in th e same direct ion t hat th e scra pers ar e loading,w h e n e v e r p o s s i b le . I t i s u s u a l l y d e s i r a b l e t o r i p a s d e e p l y a s p o s s i b le .However, i t is sometimes better to r ip the ma terial in its na tur al layers even if

t h i s is l e s s t h a n fu l l -s h a n k d e p t h . U s e t h e r i p p e d m a t e r i a l on t op o f t h eun r ipped form at ion to cush ion th e machine an d provide t ract ion . When th efinal material size must be relatively small, space passes close together. Crossr ip only when necessary to obtain th e requ ired break age. Use the fo llowingsteps to r ip material:

S t e p 1 . Position t he dozer on th e uph ill side if opera ting on a slope, about h alf th e length of th e dozer from the sta rt of the ar ea t o be ripped.S t e p 2 . Place the tr ans mission sh ift lever in forwar d, first gear .S t e p 3 . Lower th e rippers t o the ripping depth as t he dozer begins to cross thear ea to be ripped.

S t e p 4 . Raise the rippers out of the ground and then stop at th e end of the pa ss.S t e p 5 . Place the tra nsmission in reverse and ba ck th e dozer to the st art point.S t e p 6 . Position t he dozer to overlap th e previous ripping pass.Repeat steps 1 th rough 6 unt il the a rea is completely ripped.

P acked S o i l , Hardpan , S ha le , and Cemen ted G rave l

2-34. Three-shan k ripping works well in th ese mater ials . Use as ma ny shan ks

as possible to break ma terial to th e desired size.

WARNING

Maintain a straight line while ripping. Turning thedozer with the rippers in the ground will causedamage to the dozer.


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Dozers 2-17

Figure 2-12. Ripping Operations

Rock w i th F rac tu res , F au l t s , and P lanes o f Weaknes s

2-35. Use two shank s for r ipping where rocks br eak out in sma l l p ieces an dt h e m a c h i n e ca n h a n d l e t h e j ob e a s i l y. U s e on l y t h e c en t e r s h a n k i f t h emachine begins t o s tall or t he tr acks spin.

Asphal t . Raise the ripper shank t o lif t out a nd break th e mater ial. Concre te . Use one-shank ripping to sever reinforcing rods or wire

mesh effectively.Sol id Ro ck, Grani te , and Hard-to-Rip Mater ia l

2-36. Use one sha nk in h ar d- to- r ip ma ter ia l or mater ia l that tend s to break out in lar ge slabs or pieces.

WINCHING

2-37 . Winch ing i s h o is t ing o r h au l ing w ith a w inch , u s ing a cab le . Whenwinching, make su re personn el are c lear of the cable . Cables can br eak a ndcau s e s evere in ju ry. Exerci s e cau t ion w i th s u s pended loads . I f th e eng inerevolutions (speed) are t oo low, th e weight of the load m ay exceed th e engine

Three-shank ripping

Single-shank ripping Cross ripping

Two-shank ripping


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2-18 Dozers

capa c ity caus ing t he load to d rop , even t hough t he w inch i s in th e r ee l -inposition.

DOZER PRODUCTION ESTIMATES2-38. Dozer pr oduction curves give ma ximum -production valu es (in LCY perhour) for straight and universal blades based on the following conditions:

A 60-minute working hour (100 percent efficiency). Power-shift machines with 0 .05-minute fixed t imes are being used. The dozer cu t s 50 feet , then d r ift s the b lade load to dump over a h igh

wall. The s oi l dens ity is 2, 300 pounds per LCY. The coefficient of t ract ion equals 0 .5 or bet ter for crawler machines

and 0.4 or bett er for wh eel machines. H ydrau l ic-con t ro ll ed blades a r e be ing us ed .

2-39. Use th e following steps t o est imat e dozer pr odu ction:

S t e p 1 . Determine the m aximum pr oduction. Determine the estimat ed maxi-

mum production from either Figure 2-13 or 2-14, based on the type of dozerbeing used. Find the dozing distance on the bottom horizontal scale in theproper figure. Read u p vertically un til intersecting th e production cur ve for thedozer being considered then rea d th e vertical scale on t he left t o determ ine themaximu m pr oduction in LCY per h our .

Use Figure 2-13 to determine the estimated maximum production forD 3 t h r o u g h D 6 t r a c t o r s w it h s t r a i g h t b l a d e s . Th e D E U C E h a s t h esame production capability as th e D5.

Use Figure 2-14 to determine the estimated maximum production forD7 or D8 tr actors with u niversal or s tra ight blades.

CAUTIONAlways keep the winch cable in a s traight line behind themachine. For safety and maximum service life of thewinch component, decelerate the engine before movingthe winch control lever. After shifting, control the cablespeed by varying the engine speed. Winch loads at lowengine speed with the machine stationary. When movingaway from a load, operate the machine in low gear toprevent overspeeding of winch components. Do notoperate the winch for extended durations.


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Dozers 2-19

Figure 2-13. Estimated Maximum Production for D3 Through D6 TractorsWith Straight Blades

Figure 2-14. Estimated Maximum Production for D7 or D8 TractorsWith Universal or Straight Blades

S = straight bladeAverage dozing distance (feet)

S = straight bladeAverage dozing distance (feet)

1,600

1,400

1,200

1,000


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2-20 Dozers

S t e p 2 . Determine the grade correction factor(-) favorable or (+) unfavorable.Find the percent grade on the top horizontal scale of Figure 2-15 . Read downvertically and intersect the grade correction curve, then read to the right hori-zont ally and locate t he grade corr ection factor on t he vertical scale.

Figure 2-15. Dozer-Production Grade Correction Factors

S t e p 3 . Determine the material-weight correction factor. If the actual unitweight of th e ma teria l to be pushed is not ava ilable from s oil investigations, usethe average values found in Table 1-2, page 1-4 . Divide 2,300 pounds per LCYby th e ma ter ials LCY weight t o find t he correction factor. Soil den sity of 2,300pounds per LCY is a consta nt that was assumed in determ ining the m aximumproduction.

where2,300 = standard material unit weight per LCY

S tep 4 . Determine the material-type correction factor. Dozer blades aredesigned to cut material and give it a rolling effect in front of the blade. Thisresults in a production factor of 1. Table 2-4 gives the correction factors toaccoun t for how differen t m at erials beha ve in front of the blade.

Note:(-) Favorable(+) Unfavorable

Material-weight correction factor 2,300 pounds per LCY (standard material unit weight)actual material LCY weight

--------------------------------------------------------------------------------------------------------------------------------------------------------=


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Dozers 2-21

.

S t e p 5 . Determin e th e operat or correction factor (see Table 2-2, page 2-7).S t e p 6 . Determin e th e operat ing-technique correction factor from T able 2-5.

S t e p 7 . Determine the efficiency factor. In the case of a well-managed job,expect 50 min ut es of production t ime per h our .

S t e p 8 . Determin e dozer pr oduction.

S t e p 9 . Determ ine th e mat erial conversion factor, if required. To find th e totaltime (step 10) and the total number of dozers required to complete a missionwith in a given time (step 11), adjust th e volume of ma ter ial tha t is being movedand the equipment production rate per hour so that they both represent thesam e mat erial sta te. Refer to ma terial an d production sta tes as LCY, BCY, andCCY. If necessary to convert, use Ta ble 1-1, page 1-4, to find the material con-version factor. Multiply th e conversion factor by th e production per hour to findth e production per hour in a different st at e.

NOTE: This convers ion wil l not change the d ozer product ion effor t .

Table 2-4. Material-Type Correction Factors

Material State Factor for Crawler Tractors

Loose, stockpile 1.2Hard to cut; frozen, with tilt cylinderHard to cut; frozen, without tilt cylinder

0.80.7

Hard to drift; dead (dry, noncohesive)material or very sticky material

0.8

Rock (ripped or blasted) 0.6 to 0.8

Table 2-5. Operating-Technique Correction Factors

Operating Technique Factor for Crawler TractorsSlot dozing 1.2

Side-by-side dozing 1.15 to 1.25

Efficiency factor actual working minutes per hour60-minute working hour

--------------------------------------------------------------------------------------------=

Production (LCY per hour) maximum production the product of the correction factors=


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2-22 Dozers

S tep 10 . Determine the total t ime r equired in h ours.

whereQ = quantity of material to be movedP = hourly production rate per dozerN = number of dozers

EXAMPLE

Determine the average hourly production (in CCY) of a straight-blade D7 (with tiltcylinder) moving hard-packed clay an average distance of 200 feet, down a 10 per-cent grade, using slot dozing. Estimated material weight is 2,500 pounds per LCY.The operator is of average ability and will work during daylight hours. Expected effi-ciency is 50 minutes per hour.

Step 1. Uncorrected maximum production = 300 LCY per hour (Figure 2-14, page 2-19) Step 2. Grade correction factor = 1.15 (Figure 2-15, page 2-20) Step 3. Material-weight correction factor

Step 4. Material-type correction factor (a hard-to-cut material) = 0.8 (Table 2-4,page 2-21)

Step 5. Operator correction factor = 0.75 (Table 2-2, page 2-7) Step 6. Operating-technique correction factor = 1.2 (Table 2-5, page 2-21)

Step 7.

Step 8. Dozer production

Step 9. Material conversion factor = 0.63

2,300 pounds per LCY (standard material unit weight)2,500 pounds per LCY (actual material unit weight)

--------------------------------------------------------------------------------------------------------------------------------------------------------

0.92=

=

Efficiency factor 50 working minutes per hour60-minute working hour

---------------------------------------------------------------------------------- 0.83= =

300 LCY per hour 1.15 0.92 0.8 0.75 1.2 0.83190 LCY per hour per dozer=

=

Dozer production in CCY 0.63 190 LCY per hour 120 CCY per hour= =

Total time (hours) QP N--------------=

EXAMPLE

Determine the total time required to move 3,000 CCY of hard-packed clay, using one D7dozer with a production rate of 120 CCY per hour.

3,000 CCY120 CCY per hour 1 dozen------------------------------------------------------------------------------- 25 hours=


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Dozers 2-23

S tep 11 . Determin e the total nu mber of dozers required to complete th e missionwithin a given time.

whereQ = quantity of material to be movedP = hourly production rate per dozerT = maximum allowable duration, in hours

RIPP ING PRODU CTION ESTIMATES2-40. The bes t method to es t imate r ipping product ion is by working a tes ts e c t i on a n d r e cor d i n g t h e t i m e r e q u i r e d a n d t h e p r o d u c t i on a c h i ev e d .However, th e opport un ity to condu ct such investigat ions is often nonexistentan d, therefore , es t imates ar e usua l ly based on h is tor ical product ion char ts .Ripping app l icat ions wil l increase t he m achines m ainten an ce requiremen tsby 30 to 40 percent .

QUICK METHOD

2-41. A quick method to determin e an appr oximate pr oduction r ate is t o times e v er a l p a s s e s o f a r i p p e r o ve r a m e a s u r e d d i s t a n c e . T h e t i m e d d u r a t i ons h o u ld i n cl u d e t h e t u r n a r ou n d t i m e a t t h e e n d o f t h e p a s s . D e t e r m i n e a n

avera ge cycle t ime f rom th e t imed cycles . Determ ine th e qua nt i ty (volum e)from the m easured length m ult ip lied by the width of the r ipped area a nd t hedepth of penetr at ion. If measur ements are in feet, divide the nu mber of feet by27 to conver t cubic feet to cubic yards.

where27 = factor used to convert cubic feet to cubic yards

2-42. Experience has s hown tha t t he production rat e calculated by this quick meth od is about 20 percent h igher th an an accura te ly cross -sect ioned s t udy.Therefore, th e form ula for estimat ing ripping production is

whereV = measured volume in BCYT = average time in hours1.2 = method correction factor

Total number of dozers QP T-------------=

EXAMPLE

Determine how many D7 dozers (with a production rate of 120 CCY per hour) would beneeded to move 3,000 CCY of clay in seven hours.

3,000 CCY120 CCY per hour 7 hours------------------------------------------------------------------------------ 3.6 D7 dozers (round up to 4 dozers)=

Volume BCY length (feet) width (feet) penetration depth (feet)27

------------------------------------------------------------------------------------------------------------------------------------------------- -=

Ripping production (BCY per hour) VT 1.2------------------=


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2-24 Dozers

SE ISMIC-VELOCITY METHOD

2-43. Most r ipping-production cha rt s are ba sed on the relat ionsh ip between theripa bility an d th e seismic-wave velocity r esponse of a m at erial. The Figure 2-16 r ipping p erforma nce char t , which is for a 300-horsepower d ozer, a l lows thees t imat or to make a deter minat ion of the ma chines performa nce capa bi li tybas ed on seismic velocity a nd genera l rock classifications. After est ablishin g aseismic velocity, estima te pr oduction from the production chart in Figure 2-17.This chart provides a band of production rates representing ideal-to-adverserock conditions bas ed on th e following a ssum ptions:

The efficiency factor is 100 percent (60-minute working hour). The pow er-s h ift mach ines u s ed have s ing le -s hank r ipper s. The mach ine r ip s fu l l-t ime, no doz ing . The upper l imit of the band reflects r ipping under ideal condi t ions

only. If conditions such a s th ick la mina tions, vertical lamina tions, orother rock s t r uctur al condi t ions exis t which would adversely affectproduction, u se t he lower limit.

2-44. Regard less of th e seismic velocity, tooth penet ra tion is th e key to rippin gs u c c e s s . T h i s i s p a r t i c u l a r l y t r u e f o r h o m o g e n e o u s m a t e r i a l s s u c h a smudstone, clay stone, and fine-grained caliches.

Figure 2-16. Ripping Performance for a 300-Horsepower DozerWith a Single- or Multishank Ripper

Velocity in metersper second 1,000

Velocity in feetper second 1,000 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

TopsoilClayGlacial tillIgneous

GraniteBasaltTrap rock

Sedimentary rocksShaleSandstoneSiltstoneClaystoneConglomerateBrecciaCalicheLimestone

Metamorphic rockSchistSlate

Minerals and oresCoalIron ore

Ripable Marginal Nonripable

1 2 3 40


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Dozers 2-25

Figure 2-17. Estimated Ripping Production for a 300-HorsepowerDozer With a Single-Shank Ripper

whereP = maximum production for a 300-horsepower dozer ( Figure 2-17) E = efficiency factor

NOTE: Before referring to Figure 2-17 fo r determinin g a probable pro-ductio n rate, refer to Fig ur e 2-16 to ver i fy the r ipabi li ty with th e equip-ment avai lable .

3,250

3,000

2,7502,500

2,250

2,000

1,750

1,500

1,250

1,000

750

500

250

P r o

d u c

t i o n

( B C Y p e r

h o u r )

2 3 4 5 6 7 8Seismic velocity (in feet per second 1,000)

Ideal

Adverse

Production (BCY per hour per dozer) P E =

EXAMPLE

Determine how many 300-horsepower dozers are needed to rip 9,000 BCY of limestonehaving a seismic velocity of 4,000 feet per second in 7 hours. The limestone is beddedin thin laminated layers. Efficiency will be a 45-minute working hour.Maximum production for ideal conditions (thin layers) is 1,700 BCY per hour (Figure 2-17).

Efficiency-adjusted production

1,700 BCY per hour 4560------

1,275 BCY per hour=

=

9,000 BCY1,275 BCY per hour 7 hours----------------------------------------------------------------------------------- 1,300-horsepower dozer=


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2-26 Dozers

SAFETY PR ECAUTIONS2-45. Listed below are some s pecific safety precau tions for d ozer opera tors:

N e ve r ca r r y pe r son n el on t h e t r a ct or d r a wb a r. N ever tu rn a round on s t eep s lopes; back up or dow n in s tead .

K eep the mach ine in low gear w hen tow ing a heavy load dow nh i ll . Always low er the blades w hen the mach ine is pa rked . Ens u re tha t on ly one per s on i s on the mach ine w h ile i t is in opera t ion .

H o w ev e r, i n s o m e t r a i n i n g s i t u a t i on s i t i s n e c e s s a r y t o h a v e t w opeople on a dozer while it is in operat ion.


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Scrapers 3-1

Chapter 3Scrapers

The des ign o f scrapers ( t rac to r scrapers) a l lows fo r load ing , hau l ing ,dum ping, and spr eading of loose mat erials. Use a scraper for m edium-haulearthmoving operations and for moving ripped materials and shot rock.The ha ul d ista nce (zone of operat ion), the load volume, an d th e type an dg r a d e o f s u r fa c e t r a v e l e d on a r e t h e p r i m a r y f a ct o r s i n d e t e r m i n i n gwheth er to use a scraper on a part icular job. The optimu m h aul dista ncefor sma ll- an d mediu m-size scra per s is 3,000 feet or less.

DESCRIPTION3-46. Figure 3-1, page 3-2, shows a CAT 621B single-powered-axle wheelscraper. The CAT 621 is designed to operate u sing a pu sh t ra ctor for loadingassistance. The air-droppable CAT 613B wheel scraper has a chain-elevatorload ing mechan i s m th a t a l low s i t to load w ith ou t th e as s i s t an ce of a pus htra ctor. The basic operat ing part s of a scraper a re th ese:

B o w l . The bowl is the loading and carrying component. I t has acutting edge, which extends across the front bottom edge. Lower thebowl unt il the cutt ing edge enters th e ground for loadin g, ra ise it forcarry ing, and lower i t to the des ired l i ft t h ickness for dum ping an dspreading.

Apron. The apron is the front wall of the bowl. I t is independent of th e bow l and , w hen r a i s ed , i t p r ovides an open ing for load ing an dspreading. Lower th e apron du ring ha uling to prevent spillage.

Ejector. The ejector is the rear wall of the bowl. Keep the ejector inthe r ea r pos i t ion w h en load ing an d ha u l ing mate r i a l s . Act iva te th eejector t o move forwar d dur ing sprea ding to provide positive dischar geof mat erials .

CAPACITY

3-47. Struck capa city mea ns t he bowl has a full load of mater ial tha t is levelwith its s ides. Heaped capacity mean s the ma terial is heaped in the bowl an dslopes down on a 1:1 repose slope t o the sides of the bowl. In pra ctice, thesewill be LCY of ma ter ial because of how a scrap er loads. Th erefore, load volumein ter ms of BCY moved depends on both th e bowl size and t he ma teria l typebeing loaded. Th e ra ted volumetr ic capacity of the Army 621B scra per is 14-cubic-yards str uck an d 20-cubic-yards hea ped. The capacity of the CAT 613Bscraper is 11-cubic-yards hea ped. Elevating scrap ers, l ike the Army 613, arenot given str uck capacity ratings.


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3-2 Scrapers

Figure 3-18. CAT 621B Wheel Scraper

OPERATING RANGE

3-48. The optimu m ha ul dista nce for the sm all- an d medium -size scra pers is300 to 3,000 feet. There a re lar ger scrapers tha t ar e effective up t o 5,000 feet.

SELECTION

3-49. A scra per is a compromise between a ma chin e designed exclusively fore i the r load ing or h au l ing . F o r med iu m-d i s tan ce movemen t o f ma te r i a l , ascraper is bet ter t han a dozer because of its t ravel-speed advanta ge and i t i sbetter t han a t ruck becau se of its fast load time, typically less tha n a m inut e.An o t h e r a d v a n t a g e of t h e s cr a p e r i s t h a t i t c a n s p r e a d i t s o w n l oa d a n dquickly complete t he du mp cycle.

PRODUCTION CYCLE3-50. Th e pr oduction cycle for a scrap er consists of s ix oper at ions loading,hau l t ravel, dumping and spreading, tur ning at t he dump s i te , re turn t ravel,and tu r n ing an d pos i t ion ing t o load . Figu re 3-2 shows the fun ct ions of th eapron, bowl, and ejector dur ing loading, ha uling, and dumpin g.

LOADING

3-51. The CAT 621 loads with pu sh-tra ctor a ssista nce. This scra per can loadto a l imited extent without ass is ta nce, but requires pus h loading to achievemaximum product ion . Pu sher ass is tance is necessary t o reduce loading t imean d wheel spinning. Reducing scraper wheel spinning increases t ire life. Thescraper sh ould not depend on t he p ush er to do all the work. Conversely, do notspin th e scrap er 's wheels to pull away from th e pusher. Use push er assista ncefor eith er s t ra ight, downhill , or s tra ddle loadin g. Always load t he scrap er int h e d i r e c t i on o f h a u l . Do n ot t u r n t h e s c r a p e r a t t h e s a m e t i m e i t i s

Radiator

Enginecompartment

Cab (ROPS)

Hitch Draft frame

Ejector Push block(extends outbehind wheels)

Tractor Apron Bowl


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FM 5-434

Scrapers 3-3

a c ce l e r a t i n g f r o m t h e l o a d i n g o p e r a t i on . T h e C AT 6 13 i s a s e l f- lo a d i n gm a c h i n e , a n d p u s h i n g d u r i n g l o a d i n g w i ll d a m a g e t h e s c r a p e r s l oa d i n gelevator.

Figure 3-19. Functions of the Apron, Bowl, and Ejector

D ow nh i l l Load ing

3-52. Downhill loading enables a scraper to obtain larger loads in less time.Each 1 percent of favorable grade is equivalent to increasing the loading forceby 20 poun ds per ton of gross scraper weight.

S t r add le Load ing

3 -5 3 . S t r a d d l e l o a d i n g ( Figu re 3 -3 , page 3 -4 ) r e q u i r e s t h r e e c u t s w i t h ascraper . The firs t two cuts should be para llel, leaving a r idge between th e twocut s . The scra per s tr addles th is r idge of ear th t o make th e final cut. The ridges h o u l d b e n o w i d er t h a n t h e d i s t a n c e b e t w e e n a s c r a p e r ' s w h e e ls . Wi t hs tra ddle loading, t ime is gained on every th ird t r ip becau se the center s t r iploads with less resista nce than a full cut .

Direction of travel

Direction of travel

Direction of travel

Apron raised

Apron lowered

Apron raised

Ejector back in rear position during loading

Bowl lowered to desired cutting depth

Loading

Bowl raised to permit free travel

Ejector back

Carrying theload (hauling)

Ejector moves forward to empty bowl

Bowl lowered to desired spreading

Carrying theload (hauling)

Spreading theload

Ejector back


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3-4 Scrapers

Figure 3-20. Straddle Loading With Pusher Assistance

P us h-Load ing

3-54. Back-Track. Use the back- t rack push- loading technique (Figure 3-4)wher e i t i s impra ct ical to load in both d irect ions . However, th is m ethod isinefficient du e to the tim e spent in ba cking up a nd r epositioning for th e nextload.

3-55. Cha in . Use the cha in push -loading techn ique (Figure 3-4) where the cutis fairly long, ma king it possible to pick u p two or m ore scraper loads w ithou tback t r ack ing . The pu s her pu s hes one s cra per, then m oves beh ind ano the rscraper th at is moving in th e same direction in an a djacent lane.

Figure 3-21. Push-Loading Techniques

Make cuts 1 and 3, leaving a center strip (2) one-half blade width.

Back-trackloading

Chainloading

Shuttleloading

Push-tractor (dozer)

Loading Scraper

Loaded

Scraper


Loading LoadedScraper


Loading

Loaded

Scraper

Loading

Loading


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FM 5-434

Scrapers 3-5

3-56. S hu t t l e . Use the shu t t le push -loading technique (Figure 3-4) for shortcut s wher e i t i s poss ib le to load in both d irect ions . The pu sher pu shes onescraper , then tu rn s and pu shes a second scraper in the opposite direction.

Cut-and-Load Sequen ce

3-57. The scra per loadin g sequen ce is a s follows:

S t e p 1 . Use th e service brak e to reduce scrap er tr avel speed when close to thecut (loading lane), and downshift to first gear for loading.S t e p 2 . Move the ejector to th e rea r.S t e p 3 . Open th e apron partway.S t e p 4 . Lower th e bowl to an efficient cut d epth a fter t he scraper en ter s th e cut .Cont inue moving forwar d unt il th e dozer conta cts the scraper a nd begins push -ing. If th e scraper tires spin before t he dozer mak es conta ct, stop an d allow thedozer t o assist. When the d ozer ma kes conta ct, push down both th e different iallock and th e tr an smission h old pedal an d proceed in second gear. The cut shouldbe as deep a s possible, but it should allow th e scraper t o move forward at a con-stan t speed without lugging the engine. Decreas e the cut depth if th e scra per orpush er lugs or if the drive wheels slip. Use th e router bits on th e vertical side of th e bowl to gauge th e depth of cut. Once an efficient dept h of cut is determ ined,use th at sa me depth on successive passes.S t e p 5 . Mark t he cut. When cutting

Regu la te the ap ron ope

earth moving

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