ni000102- geotechnical site investigations for underground projects.pdf

7/22/2019 NI000102- Geotechnical Site Investigations for Underground Projects.pdf

1/249

Geotechnical Site Investigations for

Underground Projects

Volume 2

Abstracts of Case Histories and Computer-Based Data Management System

Subcommittee on Geotechnical Site Investigations

U.S. National Committee on Tunneling Technology

Commission on Engineering and Technical SystemsNational Research Council

NATIONAL ACADEMY PRESS

Washington, D.C. 1984

i

totheoriginal;linelengths,wordbreaks,he

adingstyles,andothertypesettingspecificformatting,however,cannotberetained,

andsometypographicerrorsmayhavebe

enaccidentallyinserted.Please

u

se

theprin

tvers

iono

fthispu

blica

tionas

theau

thori

tativevers

ion

fora

ttri

bu

tion.


2/249

NOTICE:The project that is the subject of this report was approved by the Governing Board of the NationalResearch Council, whose members are drawn from the councils of the National Academy of Sciences, the NationalAcademy of Engineering, and the Institute of Medicine. The members of the subcommittee responsible for the reportwere chosen for their special competences and with regard for appropriate balance.

This report has been reviewed by a group other than the authors according to procedures approved by a ReportReview Committee consisting of members of the National Academy of Sciences, the National Academy ofEngineering, and the Institute of Medicine.

The National Research Council was established by the National Academy of Sciences in 1916 to associate thebroad community of science and technology with the Academy's purposes of furthering knowledge and of advising thefederal government. The Council operates in accordance with general policies determined by the Academy under theauthority of its congressional charter of 1863, which establishes the Academy as a private, nonprofit, self-governingmembership corporation. The Council has become the principal operating agency of both the National Academy ofSciences and the National Academy of Engineering in the conduct of their services to the government, the public, andthe scientific and engineering communities. It is administered jointly by both Academies and the Institute of Medicine.The National Academy of Engineering and the Institute of Medicine were established in 1964 and 1970, respectively,under the charter of the National Academy of Sciences.

SPONSORS:This project was sponsored through Transportation Systems Center Contract DTRS-57-81-C-00129by the following agencies: Defense Nuclear Agency, Department of Energy, Nuclear Regulatory Commission, UrbanMass Transportation Administration, U.S. Army Corps of Engineers, U.S. Bureau of Mines, U.S. Bureau ofReclamation, and U.S. Geological Survey.

A limited number of copies are available fromU.S. National Committee on Tunneling Technology

National Research Council

2101 Constitution Avenue, NWWashington, D.C. 20418

ii

to

theoriginal;linelengths,wordbreaks,he

adingstyles,andothertypesettingspecific

formatting,however,cannotberetained,andsometypographicerrorsmayhavebe


use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


3/249

Preface

The high costs of underground construction are a major concern of both the general public and the agencies(federal, state, and local) that build or provide funds for a variety of projects. The U.S. National Committee onTunneling Technology (1974, 1978) has issued recommendations addressing certain aspects of undergroundconstruction that contribute to its high risk and high cost. However, underground construction continues to beexpensive, with project costs rising rapidly and often significantly exceeding the preconstruction estimate.

The escalation in costs is incompatible with the most advantageous use of the subsurface at a time when thedesirability of constructing underground rather than surface facilities is becoming increasingly apparent. The emphasison developing underground construction to suit a variety of purposes is expanding with our needs to conserve surfacespace as our population grows; conserve energy required for heating and cooling; provide refuge from, and mitigatethe effects of, both natural and man-made hazards; provide economical storage for food, water, and strategic goods;

provide safe disposal of toxic and radioactive wastes; and provide for subsurface energy-production projects.Improvements in cost-effectiveness, however, will be required to spur the growth of underground construction.

Considering the advantages of using underground space, it is desirable to find ways to improve the economicfeasibility of underground construction. One promising avenue is examination of the geotechnical site investigationprocess for proposed construction sites. Of all large construction efforts, underground projects among the mostcomplicated and are particularly sensitive to geotechnical considerations because the construction environment bothaffects and responds to the design and construction processes, and ultimately the operation

PREFACE iii

to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.

U.S. National Committee on Tunneling Technology. 1974. Better Contracting for Underground Construction. Washington, D.C.:National Academy of Sciences, 143 pp.

U.S. National Committee on Tunneling Technology. 1978. Better Management of Major Underground Construction Projects.Washington, D.C.: National Academy of Sciences, 151 pp.


4/249

of the completed facility. Therefore, an adequate and reliable determination of subsurface conditions is essential toevery phase of the project and, as a consequence, is a significant factor in the final cost.

The basic objective of this study is to recommend ways of planning and conducting more effective geotechnicalsite investigation programs. In turn, the results of the study are expected to provide a fundamental contribution to a

series of wider objectives: advancements in underground construction technology, improvements in controlling ormoderating construction costs, and reductions in the incidence and degree of construction hazards or failures.

METHODOLOGY

The approach adopted for this study was to examine completed projects for which the results of thepreconstruction site investigation could be related to the construction history. The procedure was designed to permit in-depth study of a large number of these projects, their respective site investigation programs, and the construction

problems and unanticipated costs, or lack thereof, as a means of determining the nature and signififance of therelationship between investigation programs and project problems and costs.

Basically, the study consisted of four main tasks, as follows:

A list of underground projects completed in the last 20 years was developed, from which 100 projects wereselected as suitable for case history study.

A case history data form was developed to relate the types and extent of the site investigations conductedprior to design and construction, as-built geological conditions, differing site conditions claims, costoverruns, and delays encountered during construction.

The case history data and additional information from the personal experiences of subcommittee memberswere evaluated and conclusions drawn, keeping in mind the rapidly advancing state of the art in design and inconstruction equipment and methods.

A computer program was developed to receive and store for future retrieval the pertinent site investigationand construction case history data.

As the study progressed, it became apparent that although there exist a large number of projects from which tochoose, obtaining complete data on any one project is extremely difficult. No one source contained all the data on any

project and a surprising amount of information had been lost or thrown away. Also, much of the data was found to beproprietary or was simply not available due to unresolved claims litigation. Due to these constraints, 87 of the original100 case histories were deemed sufficiently complete to be included in the final compilation of data presented herein.

PREFACE iv

to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


5/249

The subcommittee's method of collecting and compiling mined tunnel data, including the basic 15-page dataform, are explained in considerable detail in Volume 1, Appendix C. It should be recognized that the need for brevityin any printed form has the potential to produce distortion, as a short answer may not explain the shadings or nuancesof a particular situation. This problem was generally compensated for in the 15-page data forms by addingexplanations in parentheses and footnotes. This form became the primary record of all data collected for each projectstudied and provided the information extracted for the summary matrixes (Plates 1 and 2) in Volume 1 and the case-history abstracts and computer retrieval system presented in this volume.

The reader should understand that for general knowledge of the 87 projects reported as case histories, a study ofthe matrixes will suffice for quick correlation. For a more thorough understanding of particular projects, it will benecessary to research the abstracts, which are themselves more general than the original data forms.

PREFACE v

to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


6/249

PREFACE vi

to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


7/249

Contents

ABSTRACTS OF CASE HISTORIES 1

United States Projects

Mass Transit 6

Railroad 62

Water Conveyance, Flood Control, Dam Diversion 64

Sewage/Wastewater 126

Storm Water Detention 144

Nuclear Plant Cooling 152

Hydropower 154

Canadian ProjectsMass Transit 162

Water Conveyance 168

Sewage 170

Deep Shafts

Hydropower 174

Radioactive Waste Storage 176

Mine Access 178

COMPUTER-BASED DATA MANAGEMENT SYSTEM 181

File Definition Program 192

Format Program 196

Searching Session for Cases with Squeezing Ground 209

Searching Session for Cases in Mixed Face 226 Self-Help Guide 238

CONTENTS vii

to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


8/249

CONTENTS viii

to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


9/249

Abstracts of Case Histories

The abstracts of the 87 case histories presented herein were prepared from the 15-page data form that was thesubcommittee's basic means of compiling and recording information on every project selected for study. Therefore, thereader may find it useful to refer to Appendix C (Volume 1), which discusses the data form in detail. Many of theexplanations in Appendix C apply to the abstracts and are not repeated here. Additional items requiring furtherclarification are listed below in the order in which they appear in the abstracts.

Tunnel Construction Costs

Refers only to the cost of excavating and permanently supporting the mined (or sunk or raised) opening understudy. Total project costs are given later.Changes Awarded: refers only to cost overruns actually paid, rather than to all that were requested.

Tunnel Data

Type(s) and Length(s): as taken from final construction records, which may not always match original designdocuments.

Depth, crown to water table: a plus (+) sign indicates the water table is above the crown and a minus ( !) sign thatit is below the crown.

Geology:Soil quality--described as cohesive or granular. If cohesive, whether very soft, soft, medium stiff, stiff, very stiff

or hard. If granular, whether cemented or uncemented and then whether very loose, loose, medium dense, dense, orvery dense. (Note: for a rock tunnel not particularly affected by the overlying soil, the soil units are not described.)

Rock quality--described as weathered or unweathered, massive/ thick bedded or foliated/thin bedded, jointing

(close, moderate, wide spacing) or no jointing, shear zones or no shear zones, faulting or no faulting.

Site Exploration

Borehole tests: a dash preceding the name of a test means the actual number performed could not be determined.Lab tests: explanation applies as for borehole tests.


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


10/249

Construction

Problems Encountered: listed according to six specific categories and then described with key words/phrases.Unstable ground--blocky or slabby, running, flowing, squeezing, swelling, spalling (bursts).Hazardous environmental factors--noxious fluids, existing utilities or structures, high temperature, gas.Mechanical problems, rock and TBMs--hard or abrasive, mucking, soft bottom, face fall-out, gripper instability,

roof slabbing, pressure binding.Soft-ground methods--surface subsidence (minor = 0-3 in.; moderate = 3-6 in.; major = greater than 6 in.), face

instability, water inflow (operating nuisance, large quantity, high pressure), obstructions (boulders, piles, etc.), materialhardness, steering.

Compressed air--blowouts, fire.Other problems were sometimes added as a category because interviewers discovered a few that would not fit the

6 categories and 20 key words/phrases described above.

Subsurface-Related Extra Payments

Tabulates monies requested as opposed to monies awarded.Descriptions and Amounts: follows approximately the same categories and key words/phrases as in Problems

Encountered, above.

Remarks

Briefly describes the remainder of the items which make up the total project and the total costs involved. Inaddition, this section summarizes any other salient facts that do not fit into the rigid, abstract format yet are necessaryfor a true understanding of the project as a whole.

ORGANIZATION SCHEME

The order in which the abstracts are presented matches the arrangement used for Plate 1. The overall schemeseparates U.S. projects, Canadian projects, and deep shafts. Within those major units, the abstracts are organizedaccording to type (or purpose) of project and then grouped by owner. To assist the reader in researching the abstracts,the scheme is outlined below and lists the page numbers pertaining to the respective owners.

U.S. PROJECTS

Mass transit

Bay Area Rapid Transit District (BART), pp. 6-11.Mission Line, Contract 1M0011Mission Line, Contract 1M0031Market Street Line, Contract 1S0022


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


11/249

Baltimore Region Rapid Transit System (BRRTS), pp. 12-21.Bolton HillsLaurens StreetLexington MarketMondawmin Line NorthMondawmin Line SouthMassachusetts Bay Transportation Authority (MBTA), pp. 22-27.Red Line, Contract 091-105Red Line, Contract 091-106Porter SquareMetropolitan Atlanta Rapid Transit Authority (MARTA), pp. 28-29.Peachtree Center

Niagara Frontier Transportation Authority (NFTA), pp. 30-33.Buffalo Light Rail, Section C-11Buffalo Light Rail, Section C-31

New York City Transit Authority (NYCTA), pp. 34-49.Route 131-A, Section 1Route 131-A, Sections 2 and 3Route 131-A, Section 4Route 131-A, Section 5ARoute 131-A, Section 5BRoute 131-D, Section 5Route 131-D, Section 8

Route 133, Section 2Washington Metropolitan Area Transit Authority (WMATA), pp. 50-61.Section A-9aSection A-11aSection A-11c, Medical Center StationSection C-4Section F-1bSection G-2

Railroad

Burlington Northern Railroad (BNRR), pp. 62-63.Bonneville 2nd Powerhouse

Water Conveyance, Flood Control, Dam Diversion

Bureau of Reclamation (BuRec), pp. 64-99.Alpine Aqueduct, Section 1Bacon No. 2BousteadBuckskin MountainsBurnt Mountain and Agua FriaCarter and MormonCunninghamDoloresHades and RhodesHunter, Completion Contract

Navajo Route 44Navajo No. 5

Pacheco, Reach 2


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


12/249

Santa ClaraSouth Fork and ChapmanStillwater, Initial ContractStillwater, Completion ContractSugar Pine DiversionCalifornia Department of Water Resources (CWR), pp. 100-109.AngelesCarley V. PorterCastaic Dam DiversionSan BernardinoTehachapi 1, 2, and 3Corps of Engineers (COE), pp. 110-115.

North Fork OutletPark River AuxiliarySkiatook OutletMetropolitan Water District of Southern California (MWD), pp. 116-121.

Newhall and Balboa InletsSan FernandoTonner 1 and 2Washington Suburban Sanitary Commission (WSSC), pp. 122-125.Bi-County, East MainBi-County, West Main

Sewage/Wastewater

San Francisco Clean Water Program (SFCWP), pp. 126-129.North Shores Outfalls, N-1North Shores Outfalls, N-2Milwaukee Metropolitan Sewerage District (MMBD), pp. 130-137.Hampton Avenue

Northeast Relief, Contract 287Northeast Relief, Contract 288Northeast Relief, Contract 289New York City, Department of Environmental Protection (NYDEP), pp. 138-139.Red Hook InterceptorRochester Pure Waters District (RPWD), pp. 140-143.Cross Irondequoit InterceptorGenesee Valley Interceptor

Storm Water Detention

Metropolitan Sanitary District of Greater Chicago (MSDGC), pp. 144-151.Contract 72-049-2HContract 73-160-2HContract 73-162-2H (Part 3)Contract 75-123-2H

Nuclear Plant Cooling

Public Service Company of New Hampshire (PSCNH), pp. 152-153.Seabrook Station


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


13/249

Hydropower

California Department of Water Resources (CWR), pp. 154-155.Edward Hyatt Powerhouse

Northeast Utilities (NU), pp. 156-157.Northfield MountainPacific Gas & Electric Company (PG&E), pp. 158-159.Kerckhoff No. 2

Sacramento Municipal Utility District (SMUD), pp. 160-161.Loon Lake Powerhouse

CANADIAN PROJECTS

Mass Transit

Bureau de Transport Metropolitain (BTM), pp. 162-163.Montreal Metro Line No. 5Toronto Transit Commission (TTC), pp. 164-167.Spadina SubwayYonge Subway

Water Conveyance

Toronto Metropolitan Works Department (TMW), pp. 168-169.Easterly Filtration Intake

Sewage

Ontario Ministry of the Environment (OME), pp. 170-173.York-Durham Sewage, Contract 85York-Durham Sewage, Contract 86

DEEP SHAFTS

Hydropower

Sacramento Municipal Utility District (SMUD), pp. 174-175.Look Lake Penstock

Radioactive Waste Storage

Department of Energy (DOE), pp. 176-177.Exploratory Shaft, WIPP

Mine Access

Brunswick Mining and Smelting Corp., Ltd. (BMS), pp.. 178-179.Brunswick Shaft No. 3


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


14/249

BART MISSION LINE, CONTRACT 1MOO11

GENERAL INFORMATIONLOCATION: 23rd Street to 16th Street, San Francisco, CaliforniaPURPOSE: Running lines for subway systemOWNER: San Francisco Bay Area Rapid Transit DistrictDESIGNER: Parsons, Brinckerhoff-Tudor-Bechtel (JV)

CONTRACTOR: Kiewit-Traylor (JV)CONSTRUCTION START: February 19, 1968CONSTRUCTION COMPLETION: June 20, 1969CONTRACT FORMAT: Unit price per lin ft of completed tunnelTUNNEL CONSTRUCTION COSTSESTIMATED TOTAL: No informationBID TOTAL: $8,043,356CHANGES AWARDED: $ 125,000 (unforeseen subsurface conditions only)AS COMPLETED TOTAL: $8,168,356 (includes all claims and modifications)TUNNEL DATATYPE(S) AND LENGTH(S): Soft ground = 7,756 lin ft Total length = 7,756 lin ftLAYOUT: Twin parallel tubesSHAPE(S): CircularSIZE(S): 18 ft 0 in. diameterEXCAVATED FACE AREA(S): 254 sq ftDEPTHS: Crown to surface--maximum = 32 lin ftminimum = 22 lin ftCrown to water table--maximum = +20 lin ftminimum = +10 lin ftGEOLOGY: Soil--1st UnitIdentification/Type: sand and silty sandQuality: granularuncementeddense to very dense2nd UnitIdentification/Type: clayey sandQuality: granularuncementedmedium dense to dense3rd UnitIdentification/Type: silty clay

Quality: cohesivehardRock--1st UnitIdentification/Type: pinnacles of severely weathered clayey sandstone, shale and chertQuality: weatheredthin bedded

jointing (no information)shear zonesfaultingSITE EXPLORATIONBORINGS: Total number = 9Total length = 515 lin ftBOREHOLE TESTS: - Standard penetration tests- Advance rates recordedLAB TESTS: 17 Unconfined compression tests on soil samples

6 Sieve analyses2 Atterberg limits tests3 Mechanical analyses2 Specific gravity tests2 Consolidation tests11 Unconsolidated undrained triaxial tests


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


15/249

1 Drained triaxial test- Natural moisture tests- Dry density testsEXPLORATORY SHAFTS/PILOT TUNNELS: NoneSURFACE MAPPING: NoGEOPHYSICAL STUDIES: NoneGEOTECHNICAL REPORT: YesCONSTRUCTIONMETHOD(S) USED: Soft ground TBM (Caldwell) with compressed airPRIMARY SUPPORT: Steel liner segments, 30 in. widePERMANENT SUPPORT: Steel liner segments, 30 in. wideADVANCE RATE PER DAY: Maximum = 105 lin ftAverage = 56 lin ftPROBLEMS ENCOUNTERED: Groundwater inflow--operating nuisanceMechanical problems, rock and TBMs--mucking (muckbound; lost 3 hrs/wk average)Soft ground methods--surface subsidence (degree not known)SUBSURFACE-RELATED EXTRA PAYMENTS REQUESTED FOR CHANGES (MODS, CLAIMS,

ETC.)DESCRIPTIONS AND AMOUNTS

No descriptions available

TOTAL = $253,692

REMARKSIn addition to the mined tunnels described above, the total contract included a concrete box crossover structure, 2

ventilation structures, 4 tunnel cross passages, relocation and construction of utilities, surface improvements, and otherrelated work. The total contract price as estimated was $14,165,856; the low bid was $12,734,618 and the final totalcontract cost was $12,876,916. These figures are affected by the fact that the owner supplied the tunnel liner segments.Some information is missing because of the difficulty with follow-up interviews. Contact with the contractor wasnever made. Although contact was made with the owner, he had trouble providing some data because no one was leftwith personal knowledge of the project, and records were extremely difficult to obtain from inactive files.


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


16/249

BART MISSION LINE, CONTRACT 1MOO31

GENERAL INFORMATIONLOCATION: 24th Street to Randell Street, San Francisco, CaliforniaPURPOSE: Running lines for subway systemOWNER: San Francisco Bay Area Rapid Transit DistrictDESIGNER: Parsons, Brinckerhoff-Tudor-Bechtel (JV)

CONTRACTOR: Morrison-Knudsen, Perini, Brown & Root (JV)CONSTRUCTION START: October 8, 1968CONSTRUCTION COMPLETION: May 30, 1969CONTRACT FORMAT: Unit priced per lin ft of completed tunnelTUNNEL CONSTRUCTION COSTSESTIMATED TOTAL: No informationBID TOTAL: $9,376,130CHANGES AWARDED: No information (unforeseen subsurface conditions only)AS COMPLETED TOTAL: No information (includes all claims and modifications)TUNNEL DATATYPE(S) AND LENGTH(S): Soft ground = 8,754 lin ftMixed face = 271 lin ft Total length = 9,025 lin ftLAYOUT: Twin parallel tubesSHAPE(S): CircularSIZE(S): 18 ft 1-1/2 in. diameterEXCAVATED FACE AREA(S): 258 sq ftDEPTHS: Crown to surface--maximum = 36 lin ftminimum = 21 lin ftCrown to water table--maximum = +15 lin ftminimum = +10 lin ftGEOLOGY: Soil--1st UnitIdentification/Type: sandy clay alluvium with interbedded sand layersQuality: cohesivestiff to hardRock--1st UnitIdentification/Type: soft metasandstoneQuality: weathered

beddedjointing (no information)shear zonesfaulting

SITE EXPLORATIONBORINGS: Total number = 25Total length = 1,596 lin ftBOREHOLE TESTS: - Standard penetration tests- Water observation wells (in half of the borings)LAB TESTS: 18 Unconsolidated undrained triaxial compression tests11 Unconfined compression tests on soil samples2 Unconfined compression tests on rock core3 Permeability tests77 Unit weights14 Consolidation tests1 Drained triaxial test77 Natural moisture content tests- Specific gravity tests- Shrink/swell potential tests

- Moisture-density relations tests- Sieve analyses- Atterberg limits testsEXPLORATORY SHAFTS/PILOT TUNNELS: NoneSURFACE MAPPING: NoGEOPHYSICAL STUDIES: NoGEOTECHNICAL REPORT: Yes


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


17/249

CONSTRUCTIONMETHOD(S) USED: Soft ground TBM (Memco), with 33% under 10 psi compressed airPRIMARY SUPPORT: Steel liner segments, 30 in. wide (welded together)PERMANENT SUPPORT: Steel liner segments, 30 in. wide (welded together)ADVANCE RATE PER DAY: Left line tunnel--maximum = 102.5 lin ftaverage = 34 lin ftRight line tunnel--maximum = 75 lin ftaverage = 35 lin ftPROBLEMS ENCOUNTERED: Groundwater inflow--operating nuisance (only a minor problem)Soft ground methods--pressure bindingCompressed air--no blowouts--no fireSUBSURFACE-RELATED EXTRA PAYMENTS REQUESTED FOR CHANGES (MODS, CLAIMS,


NoneREMARKSIn addition to the mined tunnels described above, the total contract included a vent shaft, pumping station, 4 cross

passages, underpinning of structures, utility work, paving of tunnel invert, and other related work. The total contractprice as estimated was $14,594,050 and as bid was $11,679,460. These figures are affected by the fact that the owner

supplied the tunnel liner segments. The as completed final costs and detailed information on overruns were notavailable because of difficulties with follow-up interviews. Although contact was made with the owner, he had troublein providing some data because no one was left with personal knowledge of the project, and records were extremelydifficult to obtain from inactive files. However, contact was also made with the contractor and feedback from himindicates there were no significant claims and that all disputes were resolved at job level. This would seem to indicateat least some minor cost overruns due to unexpected subsurface conditions.


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


18/249

BART MARKET STREET LINE, CONTRACT 1S0022

GENERAL INFORMATIONLOCATION: 8th Street to 15th Street, San Francisco, CaliforniaPURPOSE: Running lines for subway systemOWNER: San Francisco Bay Area Rapid Transit DistrictDESIGNER: Parsons, Brinckerhoff-Tudor-Bechtel (JV)

CONTRACTOR: Morrison-Knudsen, Brown & Root, Perini (JV)CONSTRUCTION START: August 13, 1967CONSTRUCTION COMPLETION: August 13, 1968CONTRACT FORMAT: Unit priced per lin ft of completed tunnelTUNNEL CONSTRUCTION COSTSESTIMATED TOTAL: No informationBID TOTAL: $14,961,220CHANGES AWARDED: None (unforeseen subsurface conditions only)AS COMPLETED TOTAL: No information (includes all claims and modifications)TUNNEL DATATYPE(S) AND LENGTH(S): Soft ground = 10,200 lin ft Total length = 10,200 lin ftLAYOUT: Twin parallel tubesSHAPE(S): CircularSIZE(S): 18 ft 1-1/2 in. diameterEXCAVATED FACE AREA(S): 258 sq ftDEPTHS: Crown to surface--maximum = 70 lin ftminimum = 30 lin ftCrown to water table--maximum = +42 lin ftminimum = +22 lin ftGEOLOGY: Soil--1st UnitIdentification/Type: sand with interbedded silty sand, clayey sand, and sandy clayQuality: granularcemented (slightly in places)dense to very denseSITE EXPLORATIONBORINGS: Total number = 14Total length = 1,253 lin ftBOREHOLE TESTS: - Standard penetration tests- Water observation wells in a few boringsLAB TESTS: 9 Unconfined compression tests on soil4 Sieve analyses

6 Atterberg limits tests4 Specific gravity tests4 Consolidation tests2 Unconsolidated undrained triaxial tests3 Drained triaxial tests- Natural mositure tests- Dry density testsEXPLORATORY SHAFTS/PILOT TUNNELS: NoneSURFACE MAPPING: NoGEOPHYSICAL STUDIES: NoneGEOTECHNICAL REPORT: YesCONSTRUCTIONMETHOD(S) USED: Soft ground TBM (Memco), mostly in compressed airPRIMARY SUPPORT: Steel liner segments, 30 in. wide (welded together)PERMANENT SUPPORT: Steel liner segments, 30 in. wide (welded together)

ADVANCE RATE PER DAY: Left tunnel line--maximum = 72.5 lin ftaverage = 26 lin ftRight tunnel line--maximum = 82.5 lin ftaverage = 40 lin ft


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


19/249

PROBLEMS ENCOUNTERED: Unstable ground--running ground (required dewatering until compressed air system was installed to control running)Groundwater inflow--operating nuisance (caused running condition until compressed air was installed)Mechanical problems, rock and TBMs--face fallout (95 cu yd cave-in)Soft ground methods--face instability (until compressed air installed)--water inflow (even under compressed air, water leaked into tunnel around shield, at the invert, and through

cracks in the liner)SUBSURFACE-RELATED EXTRA PAYMENTS REQUESTED FOR CHANGES (MODS, CLAIMS,


NoneREMARKSIn addition to the mined tunnels described above, the total contract included ventilation and pump shaft structures,

cross passages, mechanical and electrical work, and other related items. The total contract price as estimated was$20,341,517 and as bid was $17,763,825. These figures are affected by the fact that the owner supplied the tunnel linersegments. The as completed final costs and detailed information on overruns were not available because of difficultieswith followup interviews. Although contact was made with the owner, he had trouble in providing some data becauseno one was left with personal knowledge of the project and records were extremely difficult to obtain from inactivefiles. However, contact was also made with the contractor and feedback from him indicates there were no significantclaims. It is still possible there were some minor cost overruns due to unexpected subsurface conditions.


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


20/249

BOLTON HILL TUNNELS

GENERAL INFORMATIONLOCATION: Baltimore, MarylandPURPOSE: Running tunnels for subway systemOWNER: Baltimore Region Rapid Transit System, Maryland Department of TransportationDESIGNER: Bechtel Inc.

CONTRACTOR: Fruin-Colnon CorporationCONSTRUCTION START: August 22, 1977CONSTRUCTION COMPLETION: January 9, 1979CONTRACT FORMAT: Unit price per lin ft of tunnel excavation including liningTUNNEL CONSTRUCTION COSTSESTIMATED TOTAL: $35,183,497BID TOTAL: $29,112,730CHANGES AWARDED: In litigation (unforeseen subsurface conditions only)AS COMPLETED TOTAL: Not available (includes all claims and modifications)TUNNEL DATATYPE(S) AND LENGTH(S): Soft ground = 10,030 lin ftMixed face = 1,200 lin ft Total length = 11,230 lin ftLAYOUT: Twin single-track tubesSHAPE(S): CircularSIZE(S): 19 ft 1 in. diameterEXCAVATED FACE AREA(S): 287 sq ftDEPTHS: Crown to surface--maximum = 76 lin ftminimum = 48 lin ftCrown to water table--maximum = +22 lin ftminimum = !5 lin ftGEOLOGY: Soil--1st UnitIdentification/Type: fine to coarse sand, trace siltQuality: granularuncementedvery compact2nd UnitIdentification/Type: silty clay and clay pocketsQuality: cohesivehard3rd UnitIdentification/Type: residual silty sand and sandy silt (saprolite)

Quality: granularuncementedvery denseRock--1st UnitIdentification/Type: biotite hornblende gneiss with pegmatite intrusionQuality: weatheredfoliated

jointing, close to moderate spacingno shear zonesno faultingSITE EXPLORATIONBORINGS: Total number = 60Total length = 5,111 lin ftBOREHOLE TESTS: - Falling head tests in cased boreholes1 Constant head test in cased borehole

2 Pumping tests in 2 pump test wellsLAB TESTS: - Unconfined compression tests- Triaxial tests- Consolidation tests- Sieve analysis tests


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


21/249

- Atterberg limits tests- Natural moisture contents tests- Specific gravity tests- Slaking tests on a unit block of soil

EXPLORATORY SHAFTS/PILOT TUNNELS: A shaft at station entrance, approximately 7 ft by 7 ft by 27 ft deepSURFACE MAPPING: NoGEOPHYSICAL STUDIES: NoneGEOTECHNICAL REPORT: YesCONSTRUCTIONMETHOD(S) USED: Soft ground--shield driven under compressed air (12 psi max)Mixed face--drill-and-blast (rock in invert)PRIMARY SUPPORT: Soft ground--metallic liner platesPERMANENT SUPPORT: Soft ground--metallic liner platesADVANCE RATE PER DAY: Shield--maximum = 48 lin ftOverall--average = 17.6 lin ftPROBLEMS ENCOUNTERED: Soft ground methods--obstructions (hard rock in invert requiring drill-and-blast)SUBSURFACE-RELATED EXTRA PAYMENTS REQUESTED FOR CHANGES (MODS, CLAIMS,


Obstructions = $3,200,000TOTAL = $3,200,000

REMARKSIn addition to the mined tunnels discussed above, this contract also included 5 mined cross passages, 8 tunnel

interface structures, above ground work, restoration, compaction grouting, and an instrumentation program. The totalcontract price as estimated was $44,715,777, and as bid was $41,658,000. Claims for encountering hard rock in thesoft ground tunnels are unsettled as of this writing. Borings were too far from the claim area to detect the high rockcondition.


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


22/249

LAURENS STREET TUNNELS

GENERAL INFORMATIONLOCATION: Baltimore, MarylandPURPOSE: Running tunnels for subway systemOWNER: Baltimore Region Rapid Transit System, Maryland Department of TransportationDESIGNER: Tippetts-Abbett-McCarthy-Stratton

CONTRACTOR: Granite Construction CompanyCONSTRUCTION START: March 29, 1979CONSTRUCTION COMPLETION: March 26, 1980CONTRACT FORMAT: Unit price per lin ft of tunnel excavation including liningTUNNEL CONSTRUCTION COSTSESTIMATED TOTAL: $14,757,0000BID TOTAL: $13,617,000CHANGES AWARDED: None (unforeseen subsurface conditions only)AS COMPLETED TOTAL: $14,823,670 (includes all claims and modifications)TUNNEL DATATYPE(S) AND LENGTH(S): Soft ground = 340 lin ftMixed face = 140 lin ftRock = 4,726 lin ft Total length = 5,206 lin ftLAYOUT: Twin single-track tubesSHAPE(S): Soft ground--horseshoeMixed face--horseshoeRock--horseshoeSIZE(S): Soft ground--22 ft 4-1/2 in. high by 18 ft 8 in. wideMixed face--19 ft 2-3/4 in. high by 16 ft 3 in. wideRock--19 ft 2-3/4 in. high by 16 ft 3 in. wideEXCAVATED FACE AREA(S): Soft ground--390 sq ftMixed face--264 sq ftRock--264 sq ftDEPTHS: Crown to surface--maximum = 98 lin ftminimum = 52 lin ftCrown to water table--maximum = +72 lin ftminimum = +9 lin ftGEOLOGY: Soil--1st UnitIdentification/Type: residual silty sands and sandy silt (saprolite)Quality: granularuncemented

very denseRock--1st UnitIdentification/Type: granite gneissQuality: weatheredmassive

jointing, close to moderate spacingshear zones, commonno faulting2nd UnitIdentification/Type: foliated gneissQuality: weatheredfoliated

jointing, close to moderate spacingshear zones, commonno faulting

SITE EXPLORATIONBORINGS: Total number = 47Total length = 4,396 lin ftBOREHOLE TESTS: - Falling head tests in cased boreholes- Water pressure tests using packers


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


23/249

LAB TESTS: 15 Unconfined compression tests on rock core- Triaxial compression tests on soil- Consolidation tests on soil-Aggregate hardness tests (weighted average of the hardness of the various mineral components of the rock)- Unit weight of rock cores- Grain size analysis on soil- Atterberg limits tests on soil- Natural moisture contents tests on soil- X-ray analysis of clay minerals in gouge material- Modal analysis (thin sections cut from core specimens)EXPLORATORY SHAFTS/PILOT TUNNELS: NoneSURFACE MAPPING: NoGEOPHYSICAL STUDIES: NoneGEOTECHNICAL REPORT: YesCONSTRUCTIONMETHOD(S) USED: Soft ground--heading and bench and hand miningMixed face--drill-and-blast and hand miningRock--drill-and-blastPRIMARY SUPPORT: Soft ground--ribs, liner plates, and spilingMixed face--ribs, liner plates, and spilingRock--ribs, rock bolts, and crown barsPERMANENT SUPPORT: Soft ground--reinforced cast-in-place concrete, 20 in. thickMixed face--reinforced cast-in-place concrete, 20 in. thick

Rock--reinforced cast-in-place concrete, 12 in. thickADVANCE RATE PER DAY: Rock--maximum = 32 lin ftOverall--average = 6.3 lin ftPROBLEMS ENCOUNTERED: Unstable ground--running ground (2 runs in mixed face)Mechanical problems, rock and TBMs--excessive overbreak (in rock and mixed face)SUBSURFACE-RELATED EXTRA PAYMENTS REQUESTED FOR CHANGES (MODS, CLAIMS,


Excessive overbreak in mixed face = $ 80,000Excessive overbreak in rock = $1,000,000

TOTAL = $1,080,000

REMARKS

In addition to the mined tunnels discussed above, this contract also included a cut-and-cover station, shafts, crosspassages, and restoration. The total contract price as estaimted was $37,401,000; as bid was $36,283,000 and ascompleted was $39,040,000. Claims for overbreak were not pursued further by the contractor after denial by the owner.


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


24/249

LEXINGTON MARKET TUNNELS

GENERAL INFORMATIONLOCATION: Baltimore, MarylandPURPOSE: Running tunnels for subway systemOWNER: Baltimore Region Rapid Transit System, Maryland Department of TransportationDESIGNER: Parsons, Brinckerhoff, Quade & Douglas, Inc.

CONTRACTOR: Traylor Bros., Morrison-Knudsen, Grow Tunneling (JV)CONSTRUCTION START: September 1978CONSTRUCTION COMPLETION: April 1979CONTRACT FORMAT: Unit price per lin ft of tunnel excavation including liningTUNNEL CONSTRUCTION COSTSESTIMATED TOTAL: $16,648,752BID TOTAL: $11,568,130CHANGES AWARDED: $ 250,000 (unforeseen subsurface conditions only)AS COMPLETED TOTAL: $11,818,130 (includes all claims and modifications)TUNNEL DATATYPE(S) AND LENGTH(S): Soft ground = 3,080 lin ftMixed face = 40 lin ft Total length = 3,120 lin ftLAYOUT: Twin single-track tubesSHAPE(S): CircularSIZE(S): 19 ft 1 in. diameterEXCAVATED FACE AREA(S): 287 sq ftDEPTHS: Crown to surface--maximum = 54 lin ftminimum = 44 lin ftCrown to water table--maximum = +12 lin ftminimum = +2 lin ftGEOLOGY: Soil--1st UnitIdentification/Type: fine to coarse sand, trace siltQuality: granularuncementedvery compact2nd UnitIdentification/Type: silt and clay layers (generally less than 3 ft thick)Quality: cohesivehard3rd UnitIdentification/Type: residual silty sands and sandy silts (saprolite)

Quality: granularuncementedvery denseRock--1st UnitIdentification/Type: biotite-hornblende gneissQuality: weatheredfoliated

jointing, close to moderate spacingno shear zonesno faultingSITE EXPLORATIONBORINGS: Total number = 22Total length = 1,894 lin ftBOREHOLE TESTS: - Falling head tests in cased boreholesLAB TESTS: - One-dimensional swell tests

- Unconfined compression tests- Atterberg limits tests- Grain size analysis


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


25/249

- Natural moisture content tests- Specific gravity tests- Grout injection tests (laboratory)EXPLORATORY SHAFTS/PILOT TUNNELS: NoSURFACE MAPPING: NoGEOPHYSICAL STUDIES: NoneGEOTECHNICAL REPORT: YesCONSTRUCTIONMETHOD(S) USED: Soft ground--shield (Robbins) with compressed air (6 psi average; 12 psi maximum)PRIMARY SUPPORT: Soft ground--NonePERMANENT SUPPORT: Soft ground--steel liner plate in one tube; precast concrete liner panels in the other tubeADVANCE RATE PER DAY: Shield--maximum = 54 lin ftaverage = 24 lin ftPROBLEMS ENCOUNTERED: Unstable ground--running (one 12 cu yd run at face)Soft ground methods--obstructions (hard rock in invert)SUBSURFACE-RELATED EXTRA PAYMENTS REQUESTED FOR CHANGES (MODS, CLAIMS,


Obstructions = $250,000TOTAL = $250,000

REMARKSIn addition to the mined tunnels discussed above, this contract also included a large construction shaft,

dewatering, compaction grouting, building demolition, and 2 mined cross passages. The total contract price asestimated was $21,900,485; as bid was $17,514,970 and as completed was $18,114,534. Precast concrete linersegments were used experimentally in 1,500 lin ft of tunnel.


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


26/249

MONDAWMIN LINE NORTH

GENERAL INFORMATIONLOCATION: Baltimore, MarylandPURPOSE: Running tunnels for subway systemOWNER: Baltimore Region Rapid Transit System, Maryland Department of TransportationDESIGNER: Singstad, Kehart, November & Hurka

CONTRACTOR: Clevecon, Inc.CONSTRUCTION START: November 1977CONSTRUCTION COMPLETION: April 1979CONTRACT FORMAT: Unit price per lin ft of tunnel excavation including the final liningTUNNEL CONSTRUCTION COSTSESTIMATED TOTAL: $13,402,915BID TOTAL: $10,313,225CHANGES AWARDED: $ 36,741 (unforeseen subsurface conditions only)AS COMPLETED TOTAL: $10,349,966 (includes all claims and modifications)TUNNEL DATATYPE(S) AND LENGTH(S): Rock = 6,316 lin ft Total length = 6,316 lin ftLAYOUT: Twin single-track tubesSHAPE(S): HorseshoeSIZE(S): 17 ft 9 in. high by 16 ft 3 in. wideEXCAVATED FACE AREA(S): 260 sq ftDEPTHS: Crown to surface--maximum = 100 lin ftminimum = 58 lin ftCrown to water table--maximum = +60 lin ftminimum = +30 lin ftGEOLOGY: Rock--1st UnitIdentification/Type: amphiboliteQuality: weatheredmassive

jointing, close to moderate spacingshear zones, commonno faulting2nd UnitIdentification/Type: quartz plagioclase gneissQuality: weatheredfoliated

jointing, close to moderate spacing

shear zones, commonno faulting3rd UnitIdentification/Type: tremolite gneissQuality: weatheredmassive

jointing, close to moderate spacingshear zones, commonno faultingSITE EXPLORATIONBORINGS: Total number = 32Total length = 3,441 lin ftBOREHOLE TESTS: - Falling head tests- Rising head tests- Water pressure tests

LAB TESTS: 21 Unconfined compression tests on rock core- Aggregate hardness tests- Unit weight of rock cores- Slaking tests on rock- Modal analysis (thin sections for rock identification)- Atterberg limits tests


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


27/249

- Grain size analysis- Natural moisture content tests- Unconfined compression tests on soilEXPLORATORY SHAFTS/PILOT TUNNELS: NoSURFACE MAPPING: NoGEOPHYSICAL STUDIES: NoneGEOTECHNICAL REPORT: YesCONSTRUCTIONMETHOD(S) USED: Drill-and-blastPRIMARY SUPPORT: Ribs with blocking and lagging, and rock boltsPERMANENT SUPPORT: Reinforced cast-in-place concrete, 12 in. thickADVANCE RATE PER DAY: Maximum = 20 lin ftAverage = 12 lin ftPROBLEMS ENCOUNTERED: Unstable ground--blocky (occasional rockfalls)Mechanical problems, rock and TBMs--excessive overbreakSUBSURFACE-RELATED EXTRA PAYMENTS REQUESTED FOR CHANGES (MODS, CLAIMS,


Excessive overbreak = $408,693TOTAL = $408,693

REMARKSIn addition to the mined tunnels discussed above, this contract also included a shaft and a section of cut-and-cover

tunnel. The total contract price as estimated was $21,480,808; as bid was $22,646,035 and as completed was$23,629,569. There were 5 outstanding claims at settlement that were settled with a lump sum; only one of theseclaims was geology related. The settlement amount for this claim was apportioned, based on a percentage of theoriginal asking amount of this claim and the original asking amount of all claims.


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


28/249

MONDAWMIN LINE SOUTH

GENERAL INFORMATIONLOCATION: Baltimore, MarylandPURPOSE: Running tunnels for subway systemOWNER: Baltimore Region Rapid Transit System, Maryland Department of TransportationDESIGNER: Singstad, Kehart, November & Hurka

CONTRACTOR: Clevecon, Inc.CONSTRUCTION START: July 1978CONSTRUCTION COMPLETION: December 1979CONTRACT FORMAT: Unit price per lin ft of tunnel excavation including liningTUNNEL CONSTRUCTION COSTSESTIMATED TOTAL: $15,150,330BID TOTAL: $11,877,810CHANGES AWARDED: $ 125,058 (unforeseen subsurface conditions only)AS COMPLETED TOTAL: $12,024,803 (includes all claims and modifications)TUNNEL DATATYPE(S) AND LENGTH(S): Rock = 6,600 lin ft Total length = 6,600 lin ftLAYOUT: Twin single-track tubesSHAPE(S): HorseshoeSIZE(S): 17 ft 9 in. high by 16 ft 3 in. wideEXCAVATED FACE AREA(S): 260 sq ftDEPTHS: Crown to surface--maximum = 96 lin ftminimum = 48 lin ftCrown to water table--maximum = +75 lin ftminimum = +30 lin ftGEOLOGY: Rock--1st UnitIdentification/Type: amphiboliteQuality: weatheredfoliated

jointing, close to moderate spacingshear zones, commonno faulting2nd UnitIdentification/Type: quartz plagioclase gneiss and schistQuality: weatheredfoliated

jointing, close to moderate spacing

shear zones, commonno faultingSITE EXPLORATIONBORINGS: Total number = 44Total length = 4,354 lin ftBOREHOLE TESTS: - Falling head tests in cased borings- Rising head tests- Water pressure testsLAB TESTS: 23 Unconfined compression tests on rock core- Aggregate hardness of rock- Unit weight of rock cores- Slaking tests on rock- Modal analysis (thin sections for rock identification)- Unconfined compression tests on soil- Atterberg limits tests

- Grain size analysis- Natural moisture content testsEXPLORATORY SHAFTS/PILOT TUNNELS: NoSURFACE MAPPING: NoGEOPHYSICAL STUDIES: NoneGEOTECHNICAL REPORT: Yes


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


29/249

CONSTRUCTIONMETHOD(S) USED: Drill-and-blastPRIMARY SUPPORT: Ribs and blocking with lagging, and rock boltsPERMANENT SUPPORT: Reinforced cast-in-place concrete, 12 in. thickADVANCE RATE PER DAY: Drill-and-blast--maximum = 30 lin ftOverall--average = 20 lin ftPROBLEMS ENCOUNTERED: Unstable ground--blocky (occasional rock falls)Mechanical problems, rock and TBMs--excessive overbreakSUBSURFACE-RELATED EXTRA PAYMENTS REQUESTED FOR CHANGES (MODS, CLAIMS,


Excessive overbreak = $493,413TOTAL = $493,413

REMARKSIn addition to the mined tunnels discussed above, this contract also included a vent shaft, mined cross passages,

relocation and support of utilities, and other above-ground work. The total contract price as estimated was$19,279,031; as bid was $19,518,746 and as completed was $18,659,141. There were 4 outstanding claims atsettlement that were settled with a lump sum. Only one of these claims was geology related. The settlement amount forthis claim was apportioned, based on a percentage of the original asking amount of this claim and the original askingamount of all claims.


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


30/249

RED LINE EXTENSION, CONTRACT 091-105

GENERAL INFORMATIONLOCATION: Between Porter and Harvard Squares, Cambridge, Massachusetts,PURPOSE: Running tunnels for subway systemOWNER: Massachusetts Bay Transportation AuthorityDESIGNER: Bechtel Civil and Minerals, Inc.

CONTRACTOR: Morrison-Knudsen, J.F. White and Mergentime (JV)CONSTRUCTION START: September 1979CONSTRUCTION COMPLETION: December 4, 1981CONTRACT FORMAT: Unit price per lin ft of excavation and per unit of lining componentsTUNNEL CONSTRUCTION COSTSESTIMATED TOTAL: $37,303,000BID TOTAL: $25,046,700CHANGES AWARDED: Not available (unforeseen subsurface conditions only)AS COMPLETED TOTAL: Not available (includes all claims and modifications)TUNNEL DATATYPE(S) AND LENGTH(S): Soft ground = 2,630 lin ftMixed face = 1,720 lin ftRock = 4,300 lin ft Total length = 8,650 lin ftLAYOUT: Twin single-track tubesSHAPE(S): Soft ground--circularMixed face and rock--horseshoeSIZE(S): Soft ground--23 ft 6 in. diameterMixed face and rock--21 ft 2 in. high by 21 ft 10 in. wideEXCAVATED FACE AREA(S): Soft ground--434 sq ftMixed face and rock--352 sq ftDEPTHS: Crown to surface--maximum = 105 lin ftminimum = 28 lin ftCrown to water table--maximum = +93 lin ftminimum = +10 lin ftGEOLOGY: Soil--1st UnitIdentification/Type: glacial till (mixture of sand, gravel, silt and clay)Quality: granularuncementedvery denseRock--1st UnitIdentification/Type: bedded silty argillite

Quality: unweatheredthick bedded

jointing, close to moderate spacingno shear zonesfaulting, minor2nd UnitIdentification/Type: igneous dikes and sills (with diabase and andesite)Quality: weatheredmassive

jointing, close to moderate spacingno shear zonesfaulting, minorSITE EXPLORATIONBORINGS: Total number = 59Total length = 5,571 lin ft

BOREHOLE TESTS: 46 Water pressure tests in rock with packers57 Field permeability tests in soil2 Test wells with pump tests- Oriented coring runsLAB TESTS: 24 Unconfined compression tests on rock16 Shore hardness tests15 Schmidt hardness tests


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


31/249

14 Tabor abrasion tests10 Total hardness tests32 Rock density tests- Wet-dry durability (slake) tests on rock- Petrographic examinations on rock7 Density tests on soil- Unconfined compression/Torvane/vane shear tests on soil- Moisture/Atterberg limits/sieve analysis tests- Consolidation tests- Quality (chemical concentration) tests on waterEXPLORATORY SHAFTS/PILOT TUNNELS: NoneSURFACE MAPPING: NoGEOPHYSICAL STUDIES: Seismic refraction survey for rock depthGEOTECHNICAL REPORT: YesCONSTRUCTIONMETHOD(S) USED: Soft ground--Shields (2 Elgood Mayo)Mixed face--Shields (2) and drill-and-blast and backhoeRock--drill-and-blastPRIMARY SUPPORT: Soft ground--ribs and laggingMixed face--ribs and laggingRock--steel ribs and rock boltsPERMANENT SUPPORT: Soft ground--cast-in-place concrete, 18 in. thickMixed face--cast-in-place concrete, 18 in. thick

Rock--cast-in-place concrete, 17 in. thickADVANCE RATE PER DAY: Soft ground--maximum = 48 lin ftaverage = 13.4 lin ftRock--average = 5.5 lin ftPROBLEMS ENCOUNTERED: Unstable ground--blocky, slabby--running--flowingGroundwater inflow--operating nuisanceSoft ground methods--minor surface subsidence--face instability--water inflow (operating nuisance)SUBSURFACE-RELATED EXTRA PAYMENTS REQUESTED FOR CHANGES (MODS, CLAIMS,


Blocky, slabby, unstable ground = $ 3,800,000Running, flowing unstable ground; groundwater inflow; face instability; surface subsidence = $14,700,000

TOTAL = $18,500,000

REMARKSIn addition to the mined running tunnels described above, the total contract included five mined cross passages,

two vent shafts, muck hauling by rail, and remedial work at an abandoned city dump to receive muck. The totalcontract was estimated at $55,395,920 and the low bid was $47,478,600. Actual final costs cannot yet be reported. Theowner does not wish to prejudice litigation in adjacent sections by revealing amounts settled in Contract 091-105. Theclaims were settled through negotiation rather than litigation.


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


32/249

RED LINE EXTENSION, CONTRACT 091-106

GENERAL INFORMATIONLOCATION: Between Porter and Davis Squares, Cambridge, MassachusettsPURPOSE: Running tunnels for subway systemOWNER: Massachusetts Bay Transportation AuthorityDESIGNER: Bechtel Civil and Minerals, Inc.

CONTRACTOR: Perini CorporationCONSTRUCTION START: April 4, 1979CONSTRUCTION COMPLETION: October 9, 1980CONTRACT FORMAT: Unit price per lin ft of excavation and per unit of lining componentsTUNNEL CONSTRUCTION COSTSESTIMATED TOTAL: $18,607,300BID TOTAL: $14,182,800CHANGES AWARDED: None (unforeseen subsurface conditions only)AS COMPLETED TOTAL: $13,601,912 (includes all claims and modifications)TUNNEL DATATYPE(S) AND LENGTH(S): Mixed face = 484 lin ftRock = 4,616 lin ft Total length = 5,100 lin ftLAYOUT: Twin single-track tubesSHAPE(S): Mixed face--circularRock--horseshoeSIZE(S): Mixed face--23 ft 6 in. diameterRock--21 ft 1-1/2 in. high by 21 ft 6 in. wideEXCAVATED FACE AREA(S): Mixed face--434 sq ftRock--352 sq ftDEPTHS: Crown to surface--maximum = 100 lin ftminimum = 32 lin ftCrown to water table--maximum = +84 lin ftminimum = +20 lin ftGEOLOGY: Soil--1st UnitIdentification/Type: glacial till (mixture of sand, gravel, silt and clay)Quality: granularuncementedvery dense2nd UnitIdentification/Type: marine silty clay (Boston blue clay)Quality: cohesive

medium stiff to very stiffRock--1st UnitIdentification/Type: bedded silty argilliteQuality: unweatheredthick bedded

jointing, close to moderate spacingno shear zonesfaulting, minor2nd UnitIdentification/Type: igneous dikes (with diabase and felsite)Quality: weatheredmassive

jointing, close to moderate spacingno shear zonesfaulting, minor

SITE EXPLORATIONBORINGS: Total number = 37Total length = 3,315 lin ftBOREHOLE TESTS: 45 Water pressure tests with packers9 Borehole permeability tests in soil1 Pumping test in test well


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


33/249

LAB TESTS: 43 Unconfined compression tests on rock26 Shore hardness tests20 Schmidt hardness tests18 Tabor abrasion tests16 Total hardness tests39 Rock density tests- Wet-dry durability (slake) tests on rock- Petrographic examinations on rock33 Density tests on soil- Unconfined compression/Torvane/vane shear tests on soil- Moisture/Atterberg limits/sieve analysis tests- Consolidation tests on clay- Quality (chemical concentration) tests on waterEXPLORATORY SHAFTS/PILOT TUNNELS: NoneSURFACE MAPPING: NoGEOPHYSICAL STUDIES: Seismic refraction survey for rock depthGEOTECHNICAL REPORT: YesCONSTRUCTIONMETHOD(S) USED: Mixed face--backhoe and drill-and-blastRock--drill-and-blastPRIMARY SUPPORT: Mixed face--ribs and cribbing plus crown bars and spilingRock--ribs and rock boltsPERMANENT SUPPORT: Mixed face--cast-in-place concrete, 18 in. thick

Rock--cast-in-place concrete, 17 in. thickADVANCE RATE PER DAY: Mixed face--maximum = 4 lin ftaverage = 2.5 lin ftRock--maximum = 36 lin ftaverage = 10.3 lin ftPROBLEMS ENCOUNTERED: Unstable ground--squeezing groundSoft ground methods--face instabilitySUBSURFACE-RELATED EXTRA PAYMENTS REQUESTED FOR CHANGES (MODS, CLAIMS,


NoneREMARKSIn addition to the mined running tunnels described above, the total contract included four mined cross passages

and two shafts. The total contract was estimated at $30,304,160; the low bid was $24,384,050 and the actual final costwas $23,546,070. Cost underruns were mostly due to use of less ground support than anticipated in bidding documents.


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


34/249

RED LINE EXTENSION, PORTER SQUARE STATION, CONTRACT 091-303

GENERAL INFORMATIONLOCATION: Porter Square in Cambridge, MassachusettsPURPOSE: Passenger station for subway systemOWNER: Massachusetts Bay Transportation AuthorityDESIGNER: Cambridge Seven Associates Inc.

CONTRACTOR: Slattery-MacLean (joint venture)CONSTRUCTION START: March 11, 1980CONSTRUCTION COMPLETION: June 30, 1981CONTRACT FORMAT: Unit price per cu yd of excavation and per unit of lining componentsTUNNEL CONSTRUCTION COSTSESTIMATED TOTAL: $13,035,444BID TOTAL: $21,045,650CHANGES AWARDED: $ None (unforeseen subsurface conditions only)AS COMPLETED TOTAL: $20,344,052 (includes all claims and modifications)TUNNEL DATATYPE(S) AND LENGTH(S): Rock = 490 lin ft Total length = 490 lin ftLAYOUT: Large underground chamberSHAPE(S): Split level horseshoeSIZE(S): 45 ft 7 in. high by 70 ft 6 in. wideEXCAVATED FACE AREA(S): 2,360 sq ftDEPTHS: Crown to surface--maximum = 82 lin ftminimum = 64 lin ftCrown to water table--maximum = +60 lin ftminimum = +48 lin ftGEOLOGY: Rock--1st UnitIdentification/Type: bedded silty argeiliteQuality: unweatheredthick bedded

jointing, moderate to wide spacingno shear zonesfaulting, minor2nd UnitIdentification/Type: igneous dikes (with andesite and basalt)Quality: unweatheredmassive

jointing, wide spacing

no shear zonesno faultingSITE EXPLORATIONBORINGS: Total number = 48Total length = 4,034 lin ftBOREHOLE TESTS: 3 Boreholes where oriented coring performed47 Borehole permeability tests6 Pumping tests (in conjunction with inspection shaft)- Overcoring tests (in pilot tunnel)LAB TESTS: 22 Unconfined compression tests on rock16 Rebound hardness tests16 Abrasion hardness tests22 Rock density tests- Atterberg limits tests- Gradation tests on soil

- Quality (chemical concentration) tests on waterEXPLORATORY SHAFTS/PILOT TUNNELS: One inspection shaft, 36 in. diameter, 111.5 ft deepOne pilot tunnel, 12 ft by 12 ft (length of station)SURFACE MAPPING: NoGEOPHYSICAL STUDIES: One blast vibration test in conjunction with inspection shaftGEOTECHNICAL REPORT: Yes


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


35/249

CONSTRUCTIONMETHOD(S) USED: Drill-and-blast (3-stage excavation)PRIMARY SUPPORT: Steel ribs, rock bolts, and 3 stages of shotcretePERMANENT SUPPORT: Shotcrete above and 4th stage (minimum total thickness, 15 in.)ADVANCE RATE PER DAY: Maximum = 12 lin ft (per day per stage)Average = 5 lin ft (per day per stage)PROBLEMS ENCOUNTERED: None of major consequenceSUBSURFACE-RELATED EXTRA PAYMENTS REQUESTED FOR CHANGES (MODS, CLAIMS,


NoneREMARKSIn addition to the mined station vault and crossover tunnel described above, the total contract included

miscellaneous surface work, an open-cut mezzanine structure, entrance ways, and architectural, electrical, andmechanical work. The total contract was estimated at $36,969,138; the low bid was $43,887,900; and the actual finalcost was $44,877,854. The site investigation was unusually thorough and probably cost in the neighborhood of$2,000,000 in 1976-78 dollars. This undoubtedly accounts for the fact that there were so few problems withunexpected subsurface conditions.


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


36/249

PEACHTREE CENTER STATION AND SUBWAY TUNNELS (CONTRACT CN-120)

GENERAL INFORMATIONLOCATION: Marietta Street to Mills Street, Atlanta, GeorgiaPURPOSE: Running tunnels and station structure for subway systemOWNER: Metropolitan Atlanta Rapid Transit AuthorityDESIGNER: Singstad, Kehart, November & Hurka; PB/T; Parsons Brinckerhoff; DeLeuw Cather

CONTRACTOR: Horn-Fruin Colnon (JV)CONSTRUCTION START: January 19, 1978CONSTRUCTION COMPLETION: October 17, 1980CONTRACT FORMAT: Unit prices for excavation and support items for the tunnels and stationTUNNEL CONSTRUCTION COSTSESTIMATED TOTAL: $28,119,948BID TOTAL: $23,621,507CHANGES AWARDED: $ 290,000 (unforeseen subsurface conditions only)AS COMPLETED TOTAL: $22,641,610 (includes all claims and modifications)TUNNEL DATATYPE(S) AND LENGTH(S): Soft ground = 626 lin ftMixed face = 1,291 lin ftRock--tunnel = 2,490 lin ftstation chamber = 770 lin ft Total length = 5,177 lin ftLAYOUT: Parallel single-track tunnels with stationSHAPE(S): Soft ground and mixed face--circularRock--horseshoeStation--horseshoeSIZE(S): Soft ground and mixed face--20 ft diameterRock--18 ft 9 in. high by 18 ft 9 in. wideStation--42 ft high by 60 ft wideEXCAVATED FACE AREA(S): Soft ground and mixed face--314 sq ftRock--356 sq ftStation--2,450 sq ftDEPTHS: Crown to surface--maximum = 98 lin ftminimum = 36 lin ftCrown to water table--maximum = +55 lin ftminimum = +35 lin ftGEOLOGY: Soil--1st UnitIdentification/Type: residual-micaceous silty sandsQuality: granular

uncementedmedium dense to denseRock--1st UnitIdentification/Type: decomposed metamorphic rockQuality: weatheredfoliated

jointing, moderate spacingshear zonesfaulting2nd UnitIdentification/Type: interbedded biotite, amphibole, and granitic gneissesQuality: weatheredfoliated

jointing, moderate spacingshear zones

faultingSITE EXPLORATIONBORINGS: Total number = 88Total length = 8,225 lin ftBOREHOLE TESTS: 5 Oriented integral coring tests- Standard penetration tests


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


37/249

- Single and double packer tests- Variable head permeability testsLAB TESTS: 37 Unconfined compression tests on rock core20 Triaxial tests on soil samples19 Rebound and abrasion hardness tests- Petrographic examination of rock core- Rock resistivity tests- Soil classification tests- Moisture content of soil samples- Direct shear tests on rock joints- X-ray difraction of joint filling materials- Chemical testing of groundwaterEXPLORATORY SHAFTS/PILOT TUNNELS: A 900-ft long (5 ft high and 9 ft to 14 ft wide) pilot tunnel

through crown of station; overcoring, flatjack testing, and MPBXs in pilot tunnelSURFACE MAPPING: NoGEOPHYSICAL STUDIES: NoneGEOTECHNICAL REPORT: YesCONSTRUCTIONMETHOD(S) USED: Soft ground--shield with compressed airMixed face--shield with compressed airRock--drill-and-blast with specified multiple heading and bench sequence in stationPRIMARY SUPPORT: Soft ground--noneMixed face--none

Rock--rock bolts in tunnels and stationPERMANENT SUPPORT: Soft ground--liner platesMixed face--liner platesRock--cast-in-place concrete (12 in. thick) or shotcrete (4 in. thick)Station arch--reinforced cast-in-place concrete, 2 ft 11 in. to 3 ft 6 in. thickStation walls--none or reinforced cast-in-place concrete (9 in. thick) or shotcrete (4 in. thick)ADVANCE RATE PER DAY: Soft ground or mixed face--maximum = 12.5 lin ftRock (tunnels)--maximum = 7 lin ftPROBLEMS ENCOUNTERED: Unstable ground--blocky, slabby (overbreak requiring additional support)SUBSURFACE-RELATED EXTRA PAYMENTS REQUESTED FOR CHANGES (MODS, CLAIMS,


Blocky, slabby (overbreak requiring additional support) = $1,000,000TOTAL = $1,000,000

REMARKSIn addition to the mined tunnels and station described above, the total contract also included cut-and-cover

portions, vents, shafts, entrance ways, and miscellaneous surface work. The total contract was estimated at$43,764,000 and the low bid was $42,500,000. Total final costs were not available.


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


38/249

BUFFALO LIGHT RAIL RAPID TRANSIT SECTION C-11 (Contract 1C0011)

GENERAL INFORMATIONLOCATION: Ferry to Amherst Streets, Buffalo, New YorkPURPOSE: Running tunnels for subway systemOWNER: Niagara Frontier Transportation AuthorityDESIGNER: Hatch Associates Consultants, Inc.

CONTRACTOR: Fruin-Colnon, Traylor Bros. and Onyx Construction (JV)CONSTRUCTION START: March 12, 1980CONSTRUCTION COMPLETION: January 6, 1981CONTRACT FORMAT: Unit price per lin ft of tunnel excavation, separate unit price per unit of lining componentTUNNEL CONSTRUCTION COSTSESTIMATED TOTAL: $38,922,752BID TOTAL: $28,650,062CHANGES AWARDED: In litigation (unforeseen subsurface conditions only)AS COMPLETED TOTAL: Not available (includes all claims and modifications)TUNNEL DATATYPE(S) AND LENGTH(S): Rock = 20,416 lin ft Total length = 20,416 lin ftLAYOUT: Twin single-track tubesSHAPE(S): CircularSIZE(S): 18 ft 6 in. diameterEXCAVATED FACE AREA(S): 268.8 sq ftDEPTHS: Crown to surface--maximum = 72 lin ftminimum = 18 lin ftCrown to water table--maximum = +54 lin ftminimum = +12 lin ftGEOLOGY: Rock--1st UnitIdentification/Type: solutioned dolostone and dolomitic limestone (Bertie formation)Quality: unweatheredthin bedded

jointing, moderate to wide spacingno shear zonesfaulting, minorSITE EXPLORATIONBORINGS: Total number = 48Total length = 4,027 lin ftBOREHOLE TESTS: - Packer tests on rock1 Pump test with observation wells

- Methane gas testsLAB TESTS: 48 Unconfined compression tests on rock core262 Point load tests- Total hardness and fracture toughness studies (by Cornell University)- X-ray diffraction of rock samples- Groundwater tests for pH and coliform bacteria- Clay/shale content, acidity and iron sulfide tests on rock samplesEXPLORATORY SHAFTS/PILOT TUNNELS: One inspection shaft, 36 in. diameter, 62 ft deepSURFACE MAPPING: YesGEOPHYSICAL STUDIES: NoneGEOTECHNICAL REPORT: YesCONSTRUCTIONMETHOD(S) USED: TBMs (Robbins 186-206 and 186-207)PRIMARY SUPPORT: Rock bolts (8 ft long), with ribs in limited areasPERMANENT SUPPORT: Cast-in-place concrete, 12 in. thick

ADVANCE RATE PER DAY: Robbins 186-207--average = 77.9 lin ftRobbins 186-206--average = 68.5 lin ftCombined TBMs--average = 74.8 lin ft


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


39/249

PROBLEMS ENCOUNTERED: Unstable ground--slabby (rock fallout at quarter arch points)Groundwater inflow--large quantityMechanical problems, rock and TBMs--mucking (mud from solution cavities clogged mucking system)--hard rockSUBSURFACE-RELATED EXTRA PAYMENTS REQUESTED FOR CHANGES (MODS, CLAIMS,

ETC.)DESCRIPTIONS AND AMOUNTSMucking (solution cavities, delays)

Hard rock = $8,000,000TOTAL = $8,000,000

REMARKSIn addition to the TBM mined tunnels described above, the total contract also included three subway stations, a

water discharge pipeline, and a TBM recovery shaft. The total contract was estimated at $46,427,160 and the low bidwas $38,949,800. Final cost was not available, because claims were in litigation at the time of this study.


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


40/249

BUFFALO LIGHT RAIL RAPID TRANSIT SECTION C-31 (Contract 1C0031)

GENERAL INFORMATIONLOCATION: Amherst Street to South Campus Station, Buffalo, New YorkPURPOSE: Running tunnels for subway systemOWNER: Niagara Frontier Transportation AuthorityDESIGNER: Hatch Associates Consultants, Inc.

CONTRACTOR: S&M Constructors, McHugh Construction, Kenny Construction Company (JV)CONSTRUCTION START: January 16, 1980CONSTRUCTION COMPLETION: August 1, 1981CONTRACT FORMAT: Unit price per lin ft of tunnel excavation, separate unit price per unit of lining componentsTUNNEL CONSTRUCTION COSTSESTIMATED TOTAL: Not availableBID TOTAL: $17,741,935 (unforeseen subsurface conditions only)CHANGES AWARDED: In litigationAS COMPLETED TOTAL: Not available (includes all claims and modifications)TUNNEL DATATYPE(S) AND LENGTH(S): Rock = 14,897 lin ft Total length = 14,897 lin ftLAYOUT: Twin single-track tubesSHAPE(S): HorseshoeSIZE(S): Inbound--18 ft 6 in. diameter (7,600 lin ft)Outbound--18 ft 7 in. diameter (7,297 lin ft)EXCAVATED FACE AREA(S): Inbound--268.8 sq ftOutbound--271.1 sq ftDEPTHS: Crown to surface--maximum = 49 lin ftminimum = 22 lin ftCrown to water table--maximum = +14 lin ftminimum = !6 lin ftGEOLOGY: Rock--1st UnitIdentification/Type: solutioned dolostone and dolomitic limestone (Bertie formation)Quality: unweatheredthin bedded

jointing, moderate to wide spacingno shear zonesfaulting, minorSITE EXPLORATIONBORINGS: Total number = 42Total length = 3,154 lin ft

BOREHOLE TESTS: - Packer tests on rock1 Pump test in exploration shaft (with observation wells)LAB TESTS: 14 Unconfined compression tests on rock core207 Point load tests on rock core- Groundwater tests for pH and coliform bacteria- X-ray diffraction of rock samples- Acidity, clay/shale content and iron sulfide tests on rock samplesEXPLORATORY SHAFTS/PILOT TUNNELS: One inspection shaft, 36 in. diameter, 62 ft deepSURFACE MAPPING: YesGEOPHYSICAL STUDIES: NoneGEOTECHNICAL REPORT: YesCONSTRUCTIONMETHOD(S) USED: TBM (Robbins 185-178-1 and 181-182)PRIMARY SUPPORT: Rock bolts (8 ft long), with ribs in some areasPERMANENT SUPPORT: Cast-in-place concrete, 12 in. thick

ADVANCE RATE PER DAY: Robbins 185-178--average = 52.4 lin ftRobbins 181-182--average = 56.0 lin ft


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


41/249

PROBLEMS ENCOUNTERED: Unstable ground--slabby (rock fallout at quarter arch points)Groundwater inflow--large quantityMechanical problems, rock and TBMs--mucking (mud from solution cavities clogged mucking system)SUBSURFACE-RELATED EXTRA PAYMENTS REQUESTED FOR CHANGES (MODS, CLAIMS,


Mucking (muck filled solution cavities) = $6,000,000TOTAL = $6,000,000

REMARKSIn addition to the TBM mined tunnels described above, the total contract also included two subway stations,

installation of dewatering pipelines, three shafts, and a TBM recovery shaft. No engineer's estimate was available forthe contract, but the low bid for the total contract was $35,381,213. The final contract cost was not available due tolitigation concerning claims.


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


42/249

NEW YORK CITY TRANSIT AUTHORITY ROUTE 131-A, SECTION 1

GENERAL INFORMATIONLOCATION: East 63rd and York (Manhattan) to 41st and Vernon (Queens)PURPOSE: Running tunnels for subway and railroadOWNER: New York City Transit AuthorityDESIGNER: New York City Transit Authority

CONTRACTOR: Peter Kiewit & Sons, Morrison-Knudsen Company, Slattery Associates (JV)CONSTRUCTION START: October 24, 1969CONSTRUCTION COMPLETION: October 27, 1974CONTRACT FORMAT: Unit price per cu yd of excavation with separate unit prices for support and lining

componentsTUNNEL CONSTRUCTION COSTSESTIMATED TOTAL: $26,025,500BID TOTAL: $17,231,500CHANGES AWARDED: None (unforeseen subsurface conditions only)AS COMPLETED TOTAL: $17,274,006 (includes all claims and modifications)TUNNEL DATATYPE(S) AND LENGTH(S): Rock--running tunnel = 882 lin ftstation = 596 lin ft Total length = 1,478 lin ft (includes transition through backfill concrete)LAYOUT: Single four-track tunnelSHAPE(S): Running tunnel--horseshoeStation--large chamberSIZE(S): Running tunnel--44 ft high by 40 ft wideStation--43 to 75 ft high by 42 to 60 ft wideEXCAVATED FACE AREA(S): Running tunnel--1,580 sq ftStation--1,660 to 3,540 sq ftDEPTHS: Crown to surface--maximum = 63 lin ftminimum = 47 lin ftCrown to water table--maximum = +62 lin ftminimum = +43 lin ftGEOLOGY: Rock--1st UnitIdentification/Type: granodiorite gneissQuality: unweatheredfoliated

jointing (no information)shear zonesfaulting

SITE EXPLORATIONBORINGS: Total number = 16Total length = 1,110 lin ftBOREHOLE TESTS: NoneLAB TESTS: Not availableEXPLORATORY SHAFTS/PILOT TUNNELS: NoneSURFACE MAPPING: NoGEOPHYSICAL STUDIES: NoneGEOTECHNICAL REPORT: YesCONSTRUCTIONMETHOD(S) USED: Drill-and-blast, top heading and benchPRIMARY SUPPORT: Steel sets, rock boltsPERMANENT SUPPORT: Unreinforced cast-in-place concrete, 2.5 ft thick (minimum)ADVANCE RATE PER DAY: Running tunnel--maximum = 22 lin ftaverage = 3.0 lin ft

Station tunnel--average = 2.4 lin ftPROBLEMS ENCOUNTERED: Unstable ground--blocky, slabby (excessive overbreak)Groundwater inflow--operating nuisance


to





use

theprin

tvers

iono

fthispu

blica

tionas

the

au

thori

tativevers

ion

fora

ttri

bu

tion.


43/249

SUBSURFACE-RELATED EXTRA PAYMENTS REQUESTED FOR CHANGES (MODS, CLAIMS,ETC.)

DESCRIPTIONS AND AMOUNTSNoneREMARKSIn addition to the mined tunnels described above, the total contract included su

ni000102- geotechnical site investigations for underground projects.pdf

Documents