DPL Consultants - United States Environmental … Fund Management steering Committee by DPL Consultants. Based on tha findings of that report and the subsurface investigation required

DPL Consultantsc/o Duffield Associates, Inc. 5350 Limestone Road Wilminglon, DE19808 Tel: (302) 239-6634 Fax: (302) 239-8485^•—x,———.———___________—-—____—————_———.———————————.———————____—_————————,.————__————._——————.

September 23, 1991

Ms. Paula L. RetzlerDE/MD Section (3HW25)U.S. Environmental Protection AgencyRegion III841 Chestnut BuildingPhiladelphia, PA 19107

W.O. 0323.HH.38RE: Tybouts Corner Landfill

Ward Clay Test strip

Dear Ms. Retzler:Enclosed is a copy of the proposed draft specification forperformance of a preconstruction "design" test strip forevaluation of the potential use of the Hard Clay in constructingthe "low permeability" cap for the Tybouts Corner Landfill. Thisspecification, which is forwarded at the direction of the TyboutsCorner Landfill Trust Fund, Management Steering Committee foryour review, has been prepared in response to your letter of08 May 1991.If you have any questions regarding the enclosed, please contactus.

Very truly yours,DPL CONSULTANTS, INC.

Glenn K. Elliott, P.G.Project Geologist

GKE:dolTYB4/RETZ.LTR

Enclosure: Draft Specification

cc: Chen-yu YenJohn W. Hanraond

DufftUAaotl<aa,liK, Mettalm tlmlt, IIK, Limlir, Menuly & Sktlk BntfiKmfarmw, Nfw Imy p,al Rtvtr.Nfw,m

DRAFTSUBJECT TO REVISIONDO NOT CITE OR QUOTE

TYBOUTS CORNER LANDFILL

PRECON8TRUCTION "DESIGN" TEST STRIP

{or th§WARD CLAY BORROW MATERIALS

CONTRACT SPECIFICATIONS

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•AINDEX

I. GENERAL

II. SITE PREPARATION AND RELATED WORK

III. CONSTRUCT TEST SECTIONS

IV. FIELD PERMEABILITY TESTS

V. REPORT

I. <3in«r«l.

The work described'herein consists of constructing and monitoringa test section of the low permeability layer landfill cap in

advance of full scale cap construction. The purpose is toevaluate the suitability and workability of the materialidentified as the "Ward Clay", which has been proposed as a

potential borrow source material for the remediation of the

Tybouts corner Landfill site. In addition, both field andlaboratory testing methods are established that will be used to

monitor conformance with the remedial specifications.

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A subsurface evaluation of the "Ward Clay" was performed at the

"Pit 3" parcel for the purpose of prequalifying the material as aborrow source for the Tybouts Corner Landfill Remediation. Pit 3is a mined out sand and gravel borrow site located approximately2,000 feet southwesterly of the Tybouts Corner Landfill. That

evaluation indicates that the soils of the Pit 3 area can be

characterized into two (2) textural horizons: a sandy overburden

stratum of variable thickness, overlying massive, variegatedsilt-clay deposits of the Potomac Formation. These silt-claysgenerally consist of low plasticity clay with interlayered highplasticity silt-clays. Laboratory tests performed as part of theevaluation indicate that permeability values in the range of? l X10'7 cm/sec or less can be achieved at a compaction of

. approximately 90% standard Proctor density. The results of thatevaluation are summarized in the report entitled SubsurfaceEvaluation "Ward Clay" Borrow Source Prequalification, preparedby DPL Consultants and dated 2 August 1990.

The work described herein is divided into the followingcomponents:

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A. Site Preparation and Borrow Identification.

Identify and locate the proposed test strip site and

borrow area(s) in order to establish the work area and

the materials to be utilized in the test section

construction. The intention is to identify potentialborrow areas to provide the two (2) material types: low

plasticity clay (CL) and high plasticity clay-silt (CH,

MH), previously identified as being available from the"Ward Pit 3" area.

Obtain bulk samples of the proposed "borrow" materialsand perform laboratory testing to establish thedensity-moisture-permeability relationship for the two

(2) soil types.

B. construct Test Sections.

Construct a test strip section for each of the two (2)

material types, Monitor construction of the test stripsections. Perform field testing of the compacted

material with respect to compaction effort, material

density and moisture content. Extract samples from the

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test section for laboratory permeability testing ofcompacted material.

c. Field Permeability Tests.

Perform field permeability testing on the constructedtest section.

D. Report.

Prepare a report correlating the field and laboratoryresults of the testing performed and make

recommendations towards the following:

1. Equipment type, size and procedure for

construction2. Material lift thickness3. Compaction modes4. Number of compaction equipment passes5. Hatting or drying equipment procedures6. Materials conditioning equipment

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7. Frequency and distribution of both field andsupplementary laboratory tests that should berequired for full scale cap constructionmonitoring.

The site preparation, borrow source identification, test sectionconstruction and field testing shall be conducted at the "WardFit 3" area. The Contractor shall assume that all work describedherein will be conducted in Level "0", as described in theOccupational Safety and Health Guidelines for Hazardous WasteSite Activities, October 1985, by NIOSH, OSHA, USCG, and USEPA.

II. sit* Preparation and Borrow identification.

The Contractor shall review the report titled Subsurface .Evaluation "Ward Clay" Borrow Source Evaluation, dated2 August 1990, that was prepared for the Tybouts Corner LandfillTrust Fund Management steering Committee by DPL Consultants.Based on tha findings of that report and the subsurfaceinvestigation required herein, the Contractor shall identify andlocate the proposed test strip section site and borrow areas.

To identify the borrow area the Contractor shall performsubsurface borings within the approximately 150 ft. x 300 ft.

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tract shown in Figure 1. As identified by the above mentionedreport, it is assumed that high plasticity soils should beencountered near TP-E and that low plasticity soils should beencountered near TP-H. The Contractor shall physically delineatethese areas in the field and verify these assumptions. The

Contractor shall perform twenty-eight (28) subsurface borings,fifty feet on canter within the tract. The borings shall beterminated at a depth of six feet below existing grade, withcontinuous, one (1) foot depth interval soil samples obtained forthe full depth of each (total 168 samples). The Contractor shallprepare descriptive logs for each boring, based on the standardpractice for Description and Identification of Soils(Visual-Manual Procedura) [ASTM: D 2488-84].

For the soil samples obtained, the Contractor shall perform thefollowing tests:

Teat No., of Tests

o Soil Moisture Content, ASTH-D 2216 40

o Silt-clay content, ASTM-D 1140 40

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o Soil Plasticity (Atterberg Limits) 6(minimum)

The test samples shall be selected to characterize the subsurfacesoils within the indicated areas and identify preferred borrowareas for the teat strip construction.

Based on the data obtained from the above tests, the Contractorshall delimit the areas of borrow for test section constructionand determine the appropriate areas for required bulk sampling.Bulk samples of both high and low plasticity soils shall beobtained and the following soil engineering property tests shallbe performed:

o Classification of Soils for Engineering Purposes,ASTM-D 2487.

o Moisture-Density of Soils and Soil Aggregate MixturesUsing 5.5-lb (2.49-kg) Rammer and 12-in. (305-itun) Drop,ASTM: D 698.

o Moisture-Density of Soils and Soil Aggregate MixturesUsing S.S-lb (2.49-kg) Rammer and 12-in. (305-mm) Drop,(test samples shall consist of 4 layers, each layer•o

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shall receive 9 blows, and compacted in the same four(4) inch mold as specified in ASTM: D698).

o Moisture-Density Relations of Soils and Soil AggregateMixtures Using 10-lb (4.54-kg) Rammer and is-in. (457-nun) Drop, ASTM: D 1557

o "Falling Head" test, based on U.S. Army Corps ofEngineers procedure for Permeability Test WithConsolidometer (EM 1110-2-1906), or other methodapproved by the Trust in writing, prior to the start oftesting,

Permeability testing shall be performed on a total of three (3)samples for each material type for each compaction effort, .specified above. Test samples shall be compacted at theindicated appropriate moisture content to acieve compaction inthe following ranges for each compactiva effort:

Moisture Content compaction

o dry of optimum 95% - 100%o wet of optimum 92% - 95%o wet of optimum 87% - 90%

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(9 permeability tests per material type; total 18 tests)••*«.

The Contractor shall, based on the results of the testingrequired above, refine the limits of the areas of borrow for thetest sections, as necessary.

III. Construct Test saotioni.

A. General.

The Contractor shall expose the borrow material by removing theoverburden soils and temporarily stockpiling those soils in anarea adjacent to the area of work.

The Contractor shall construct two (2) test sections; eachsection being 20 feet wide by 70 feet long by 24 inches thick.One test section shall be constructed using low plasticity soilsand the other test section shall be constructed using highplasticity soils.

The Contractor shall construct a suitable base on which the testsections are to be constructed using the available granularoverburden materials from the borrow areas. The contractor shallclear all vegetation from the test section area and proof-roll

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the base material in a manner that is satisfactory to the Trust.

B. Material.

Material from the borrow areas shall be prepared in accordancewith the requirements specified herein. Soils shall be amendedby the Contractor, as necessary, at the borrow area. Based., onthe results of the soils engineering property testing, thecontractor shall adjust the borrow materials to the appropriatemoisture content before placement in the test sections. It isanticipated that to achieve the desired compaction, it will benecessary to maintain the borrow materials at a moisture content,"wet" of optimum, based on the results of the testing required onthe bulk samples, but in no instant shall it be less than 2%above the optimum moisture content as defined by the StandardProctor Test (ASTM: D 698). The desired compaction shall bebased on the results of the testing required on the bulk samples,but in no instance shall it be less than 90% of the maximum drydensity, as determined by the standard Proctor test (ASTM-D 698).

The 24 inch test sections shall be constructed in four (4)uniform lifts with a compacted thickness not to exceed six (6)inches., The Contractor shall amend the soils, as necessary, at

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the borrow area in order to achieve clod sizes no greater than'•«*

three inches in their largest dimension.

C, Equipment.

The Contractor shall use standard heavy construction equipmentfor the preparation of the borrow areas and the construction ofthe test sections and their subbases, The equipment used shallbe appropriate to the extent that their use during full scaleborrow material preparation/extraction and landfill capconstruction is reasonable and feasible, as determined toy theTrust.

•̂Mtr

The contractor shall utilize a sheepafoot roller to achieve the• desired compaction of the soils used for the construction of .the

test sections. Each lift shall be sealed with a smooth drumroller and scarified; its moisture adjusted, as necessary, beforethe placement of the subsequent lift. Care shall be taken by theContractor to ensure that the proper bonding between lifts isachieved.

Equipment type, weight, compaction mode and spaed of operationshall be appropriate to the task in which it is intended andshall be acceptable to the Trust prior to the start of the work.

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DRAFTSUBJECT TO REVISION00 NOT CITE OR QUOTE

The Contractor shall obtain "undisturbed" samples from thecompleted test sections, Two (2) samples from each test section[four (4) total] shall be obtained in accordance with theStandard Practice for Thin-walled Tube Sampling of Soils, ASTM-D1587. The contractor shall perform laboratory permeabilitytests, in accordance with the methods specified herein, on thesamples obtained*

D. Site cleanup.

The Contractor shall return all stockpiled cover soils to theborrow areas and regrade those areas to blend with thesurrounding topography. . The test section constructed shall beleft in place. The site shall be restored to a condition that issatisfactory to the Trust,

17. field Ptrmwbility Ttiti.

The Contractor shall conduct two (2) field permeability tests oneach of th* completed teat sections; four (4) total. Testingprocedures shall ba in conformance with the standard Test Methodfor Field Measurement of Infiltration Rate Using a Double-RingInfiltrometer with a Sealed-Inner Ring, ASTM-D 5093-90 or other

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method acceptable to the Trust and approved, in writing, prior tothe performance of testing.

Testing shall be performed until such time as it ia determinedthat the in-situ permeability of the constructed test sectionshave met the minimum requirements of the low permeability layercomponent of tha proposed landfill cap for the Tybouta CornerLandfill Remediation or until it ia determined, in the opinion ofthe Trust, that no such determination can be made,

V. Report.

*The Contractor shall prepare and submit a report of his findingsto the Trust. The report shall document the phases of thetesting and the construction of the teat sectiona, shall displaythe data generated in an appropriate form and shall makerecommendations towarda the followingi

1. Equipment type, size and speed of operation.2. Material lift thickness.3. Compaction modes4. Number of compaction equipment passes.5. Wetting or drying equipment procedures.6. Materials conditioning equipment.

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7. Frequency and distribution of both field andsupplementary laboratory tests that should berequired for full scale cap constructionmonitoring.

The Contractor shall conclude, based on the results of thetesting required herein, on the applicability of the "Hard..Clay"us the low permeability layer component of the proposed TyboutsCorner Landfill Remediation.

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Documents

DPL Consultants - United States Environmental … Fund Management steering Committee by DPL Consultants. Based on tha findings of that report and the subsurface investigation required