basic soils presentation

BASIC SOIL

LEARNING OBJECTIVESWhy we test soils.Understand the role of project personnel.Awareness of applicable safety requirements:Radiation safetyExcavation safetyWorking around earthmoving equipmentBasic concepts.Obtain samples for laboratory testing.

*

LEARNING OBJECTIVES (CONTD)Basic familiarity with some laboratory tests.Introduction to soil classification (USCS).Interpret earthwork specifications and site plans.Familiarity with compaction equipment and proper use.

*

LEARNING OBJECTIVES (CONTD)Knows how to perform field density and moisture tests:Sand coneNuclear gauge

*

BEFORE WE STARTSafety is non-negotiable!Approved construction drawings and specifications must be used!

*

WHY DO WE TEST SOILS?Foundation for most structures, and we want to build on Good Stuff.Reduce potential failures.Quality control.

*

SAFETYHard hat is required at ALL TIMES.Safety glasses are required at ALL TIMES.Proper clothing is required at ALL TIMES.No shortsShirts with sleeves on at ALL TIMESAvoid overexposure to the sun or cold.

*

SAFETY (CONTD)Watch for moving equipment:Announce your presenceBe visibleTrench Safety

*

TRENCH SAFETY SUMMARYNo protective system needed if:Entirely in stable rock, orExcavation less than 5 feet (4 feet in some jurisdictions), andNo indicators of potential cave-in (Competent person).Otherwise, dont go in.

*

*

TRENCH SAFETY SUMMARY (CONTD)Reasonable exits within 25 feet if 4 foot deep or more:Stairs, ramps or laddersNo soil or rock stepsHazardous atmosphere check before entry if problems could be reasonably expected and if more than 4 feet deep.

*

TRENCH SAFETYSUMMARY (CONTD)Material and equipment at least 2 feet back from edge.Competent person must inspect daily.> 20 feet: designed by an engineer.Trench boxes must extend 18 inches above edge.

*

TRENCH SAFETYSUMMARY (CONTD)Notify the site superintendent if you suspect unsafe conditions.Document your observations in detail.Do not enter an unsafe trench!Never stay in a trench box when its moved.

*

RADIATION SAFETYRadiation safety: Wear dosimeter properlyGauge must be within your control at all times (within 10 when using).Do not expose the source.Wear reflective vest!

*

RADIATION SAFETY (CONTD) If an accident:Stop all activity near incidentTape off area 15 feet around the gaugeCall the RSO immediatelyDo not leave the area

*

LEARNING OBJECTIVESWhy we test soils.Understand the role of project personnel.Awareness of applicable safety requirements:Radiation safetyExcavation safetyWorking around earthmoving equipmentBasic concepts.Obtain samples for laboratory testing.

*

ORGANIZATIONS AND STANDARDSAASHTO: American Association of State Highway and Transportation Officials.ASTM: American Society for Testing and Materials.

State Transportation Agencies:VDOTMHDTxDOTetc.USACE: U.S. Army Corps of Engineers.

*

BASIC SOIL CONCEPTS Soils/Rock form the foundation for virtually all buildings, roads, and structures.

Understanding of soil characteristics and how they respond to structural loads is important in design & construction.

Soils formed naturally from weathering of rock.

*

*

SOIL MECHANICSSoils are defined or categorized by particle size and plasticity.Each category of soil or rock has different engineering characteristics.Moisture content significantly effects how soils behave.Compaction influences engineering characteristics.

*

*

PARTICLE SIZESoil/rock categories based on particle sizes:BoulderCobbleGravelSandSilt/Clay

*

*

PARTICLE SIZE AND DENSITY OF SOILRocks are more dense than soil.The larger the particles are in a given volume, the greater the density.

*

*

GRAVEL Particle sizes smaller than 3 inches in diameter and retained on No. 4 sieve.

*

*

SAND

Pass No. 4 sieve, (4.75 mm) and retained on No. 200 (75 m) sieve.

*

*

GRAVEL & SAND Good Structural fill material.

Good for Drainage (pervious).

Recommended for backfill of walls.

Good roadway/slab subgrade material.

*

SILT AND CLAY

Pass No. 200 (75 m) sieve.

*

*

SILT & CLAYLow permeability (less pervious).Excellent for dam and pond construction.Relatively weak for road subgrades.Very sensitive to moisture.Shrink/swell potential.

*

MOISTURE CONTENT (w)Influences ability to compact soils.Changes characteristics of silts and clays.

w = x 100

Weight of water = weight of wet soil weight of dry soil*Weight of waterWeight of dry soil

COMPACTIONDensification of soils by mechanical means.Higher densities (dry density) usually improve engineering properties.

*

OBTAINING SAMPLESDetermine where the sample should be taken:Sample the same that will be placed?What type of tests will be run? Proctor: sample from the source of the fill.CBR: sample from the subgrade.

*

OBTAINING SAMPLES (CONTD)Must have enough to run required tests: 35 lbs for standard Proctor65 lbs for CBR and ProctorAsk if you are not sure!

*

COMMON LABORATORY TESTSAtterberg Limits Tests:Test the plasticity of the soil.The higher the plasticity, the worse the soil is for structural backfill.Liquid Limit (LL) - Moisture content at boundary of plastic and semi-liquid states.

*

COMMON LABORATORY TESTS (CONTD)Atterberg Limits Tests (contd):Plastic Limit (PL) - Moisture content at boundary of plastic and semi-solid states. Plastic Index (PI) - Moisture content range over which a soil acts plastic. PI = LL PL.

*

ATTERBERG LIMITSAND SOIL STATES*

Increasing W Plastic Limit Liquid Limit

Plastic StateSemi-SolidStateSolidState

LiquidState

Plasticity Index

COMMON LABORATORY TESTS (CONTD)Grain-Size Analysis:Determines the % of different sizes of the soil particles in a sample.Sample usually dried and sent through a series of sieves.#4 sieve has 4 openings per inch.#10 sieve has 10 openings per inch.3/8-inch sieve has openings that are 3/8-inches wide.#200 has 200 openings per inch.

*

COMMON LABORATORY TESTS (CONTD)Grain-Size Analysis (contd):% Retained.% Passing. Sample distribution graphs at Tab II.

*

SAMPLE GRAIN SIZEDISTRIBUTION GRAPH*

COMMON LABORATORY TESTS (CONTD)Proctor Analysis / MoistureDensity Relationship:Density is the mass per unit of volume (lb/ft3). Soil is made up of, air, water and particles.By adjusting the water content, we can obtain different densities.By adjusting the compactive effort, we can obtain different densities.

*

COMMON LABORATORY TESTS (CONTD)Oversize material is removed.Obtained by molding samples at different moisture contents and a constant compactive effort. The top of the curve is the uncorrected or as tested Maximum Dry Density.The corresponding moisture content is the uncorrected or as tested Optimum Moisture Content.Sample Report at Tab II.Whats this zero air voids curve?

*

SAMPLE PROCTOR CURVE*

SLCP

Engineering Consulting Services, Ltd

Soils Laboratory Calculation Program1Chantilly, Virginia

PROCTOR Version 1.A.3 November 19970.0

Chantilly, Virginia

Baltimore, Maryland

Richmond, Virginia

Select Your OfficeVirginia Beach, Virginia

Research Triangle Park, North Carolina

Charlotte, North Carolina

Fredericksburg, Virginia

Greensboro, North Carolina

Roanoke, Virginia

Atlanta, Georgia

Greenville, South Carolina

Frederick, Maryland

Williamsburg, Virginia

Chicago, Illinois

San Antonio, Texas

Winchester, Virginia

&A

Page &P

Chantilly, Virginia

Baltimore, Maryland

Richmond, Virginia

Virginia Beach, Virginia

Research Triangle Park, North Carolina

Charlotte, North Carolina

Fredericksburg, Virginia

Greensboro, North Carolina

Roanoke, Virginia

Atlanta, Georgia

Greenville, South Carolina

Frederick, Maryland

Williamsburg, Virginia

Chicago, Illinois

San Antonio, Texas

Winchester, Virginia

Proctor

Engineering Consulting Services, Ltd.\A{GOTO}C5~'{?}~

Maximum Density Determination{GOTO}H5~'{?}~

ASTM D-698, D-1557, VTM-1-2000{GOTO}B7~^{?}~

Project Name:Fortuna Village Center{GOTO}E7~^{?}~

Project No.:9117-BDate:8/27/04MoldDiameterVolume{GOTO}H7~'{?}~

Sample #:S-4Street:North West of Site East of Dumfries Road Pit 1Station:_A3.9960.03329{GOTO}C9~{?}~

Description:Clayey Sand YellowClassification:SCB3.9910.03321{GOTO}C11~{?}~

Natural MC:26.3% - #200:26.0LI:C3.9910.03325{GOTO}G11~{?}~

LL :41.023.0PI:18D3.9920.03328{GOTO}E16~^{?}~

ML-25.9970.07491{GOTO}G16~"{?}~

Test Method:VTM-1Number of Points:Method:_ML-36.00.07521{GOTO}D21~{?}~

ASTM D1557c{GOTO}D22~{?}~

HammerBlows /NumberMoldMoldMoldRammer{GOTO}E21~{?}~

WeightLayerof LayersDiameterNumberVolumeType{GOTO}F21~{?}~

5.525.03.03.99D0.03328Manual{GOTO}G21~{?}~

{GOTO}D31~{?}~

Density Determination{GOTO}D32~{?}~

Trial #1.02.03.04.05.0{GOTO}D33~{?}~

Wet Wt Mold + Soil6035612061175898113.8108.8106.624105.536104.448103.36102.27199999999999101.184

Wt Mold4210421042104210017.79600338475558620.3159041394335521.4863723267084722.0897064438604822.70561002178649423.3344799908267423.97673017197423624.6327921849743