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CLAY BARRIER WALL· COARE.ebJiT,. . ....

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Yard 520 S~:IiJf,FillSite.: .. '·P:i1i¢s, I~d_ialla

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ENVIRONMENTAL AND GEOTECHNICAL SERVICES Chicago; Illinois -Elkhart, ihdid~a

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TABLE OF CONTENTS

Yard 520 Solid Fill Site Clay Barrier Wall CQA Report

December 1995

I 1. 0 EXECUTIVE SUMMAR y ............................................................................................... 1 ' i

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1.1 General ................................................................................................................. 1

1.2 Report Organization ............................................................................................. 1

1.3 Regulatory Basis ................................................................................................... 1

2.0 SITE PREPAR.ATION ...................................................................................................... 2

2.1 Clearing and Grubbing .......................................................................................... 2

2.2 Coordinate System ................................................................................................ 2

2.3 Subgrade Development ......................................................................................... 2

3. O BARRIER CONSTRUCTION .......................................................................................... 3

3. I Clay Placement ....... · ............................................................................................... 3

3.2 Clay Barrier Construction Quality Evaluation Testing ........................................... 3

3 .2.1 Permeability Testing for Construction Quality Evaluation ....................... 4

3 .2.2 Proctor Testing for Construction Quality Evaluation ............................... 4

3.2.3 Atterburg Limits for Construction Quality Evaluation ............................. 4

3 .2.4 Particle Size Analysis for Construction Quality Evaluation ...................... 4

3.2.5 Field Compaction Testing for Construction Quality Evaluation ............... 5

3.2.6 Moisture Content Testing for Construction Quality Evaluation ................ 5

3.3 Conclusion ............................................................................................................. 5

ENGINEERING CERTIFICATION ....................................................................................... 6

Attachment I

Attachment 2

Attachment 3

Attachment 4

Attachment 5

Daily Reports

Soil Testing

LIST OF ATTACHMENTS

Subgrade Verification

.. <:;omp~stion Testing 1

· Latfor~tory Testing · · ; . . .

Photographic Log

Construction Quality Assurance Plan

Select Design Drawings

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1.0 EXECUTIVE SUMMARY

1.1 General


December 1995

This report assembles the majority of the Construction Quality Assurance (CQA) documentation

performed during the construction of the Clay Barrier Wall at the Yard 5 20 Solid Fill Site. All

work was performed in accordance with the CQA Plan developed for the project as submitted to

the Indiana Department of Environmental Management (IDEM) and attached as Attachment 4 of

this report.

After excavating and regarding the subgrade to approximately 3 feet below the top of the clay

liner elevations of the Type IV Fill Area, a clay barrier wall consisting of approximately 17 feet of

compacted clayey soil possessing a hydraulic conductivity of 1 x 10-<> CID/s or less was installed.

The clay barrier wall was extended up to the design elevations of the service road located between

the two landfills. These design elevations are shown on Drawing 3 in Attachment 5.

The Clay Barrier Wall construction has been completed in accordance with the intent of the plans

and specifications. Copies of the pertinent design plans are included in Attachment 5.

1.2 Report Organization

Following this summary is a brief narrative describing each of the major tasks related to the

barrier construction. Within each section of the narrative, references are made to the supporting

documents attached to this report.

1.3 Regulatory Basis

The Yard 520 Solid Fill Site is owned and operated by Brown, Inc. The site is a Restricted Waste

Site and for the last 7 to 8 years has received only flyash from the nearby Michigan City

Generating Station ofNIPSCO. On May 10, 1995, an Agreed Order was entered by IDEM and

Brown, Inc. in which Brown, Inc. agreed to implement the plan previously submitted and

approved for the construction of a barrier between the Type II inactive fill area and the active fill

area. This barrier was completed up to the existing elevations on August 25, 1995. Extension of

the barrier up to the design road elevations shown on Drawing 3 in Attachment 2 was completed

on September 6, 1995. The following sections of this report document the construction of the

Clay Barrier Wall.

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2.0 SITE PREPARATION

2.1 Clearing and Grubbing

All vegetative matter within ten feet of the barrier wall was removed.

2.2 Coordinate System


December 1995

The site was surveyed in a grid pattern so that locations of sample and testing points made during

construction were readily discernible by the field engineer/technician. This grid system consisted

of equidistant spaced parallel lines, 200 feet on center, projecting parallel and perpendicular to

Route 20 as shown on the drawings (see Attachment 5), within the limits of the landfill. In

addition, two permanent project benchmarks were placed in the vicinity of the landfill for

" l correlation of lift thickness and landfill cap construction. The proposed location of the barrier " l

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wall was surveyed and staked prior to commencing earthmoving activities.

2.3 Subgrade Development

Prior to Barrier construction, the existing topography was excavated to approximately 3'-4' below

the top of the existing clay liner of the active fill area. This elevation varied from 598 feet MSL

near the east end of the barrier wall to 603 feet MSL near the west end. Prior to placement of any

fill, exposed subgrade areas were tested with a calibrated pocket penetrometer. This test involved

pushing a spring-loaded piston, 0.25 inch in diameter, into the subgrade and measuring the spring

deflection, which has been correlated to shear strength. Any subgrade areas which were judged to

contain soft or unacceptable soils were overexcavated and recompacted as part of the Clay

Barrier installation discussed in Section 3.0.

The subgrade was approved in sections of approximately 75' to 150' in length. Several pocket

penetrometer readings were taken in each section and the maximum and minimum readings for

these sections are recorded in Attachment 1. These results show that the subgrade was comprised

of very stiff to hard clays .

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3.0 BARRIER CONSTRUCTION


December 1995

The clay barrier serves to separate the four closed Type II landfill cells from four operating Type

IV cells. As the Cation Exchange Capacity (CEC) of the clay is less than 10, IDEM has specified

this barrier to be ten-feet thick. This barrier was extended up to the proposed grade of the service

road between the two fil1 areas. Its specific location is shown on the Drawings in Attachment 5.

3.1 Clay Placement Clay placement along the barrier alignment did not take place until the existing subgrade soil in

that area was in compliance with the project specifications. A minimum thickness of ten-feet of

clay was placed, compacted and graded as part of the landfill barrier system. The typical wall

v.ridth was approximately 10 feet, 3 to 5 feet wider when the lifts were above existing grade.

Grading of the clay was performed in a manner as shown on the Drawings.

All clay was compacted to at least 95 percent of the maximum dry density at a moisture content

zero to five percent over optimum, as determined by the Modified Proctor Compaction Test

(ASTM D 1557). The moisture-density curve for the clay is included in Attachment 2.

The clay was placed and compacted in nine-inch loose lifts. Compaction was performed using a

sheepsfoot roller and a backhoe-mounted hydraulic vibratory compactor. Smooth surfaces

between clay lifts were avoided. Any standing water or soft soil were removed and local

depressions filled prior to the placement of the next lift. Any exposed soil which dried and

exhibited desiccation cracking was wetted and recompacted in accordance with the project

specifications, prior to placement of additional lifts. The photographic log in Attachment 3

documents select barrier construction activities.

The borrow area for all clay used in the barrier wall was designated by the Engineer.

3.2 Clay Barrier Construction Quality Evaluation Testing

During clay barrier construction, soil testing for construction quality evaluation was performed as

described below. The dimensions of the barrier wall were approximately 1700 feet long by 1 O

feet wide (3 - 5 feet wider for lifts installed above existing grade) by 17 feet tall, thus the quantity

of clay installed was between 10,700 cubic yards and 13,000 cubic yards. The frequency on all

laboratory testing was based on this as-installed volume .

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3.2.1 Permeability Testing for Construction Quality Evaluation


December 1995

For construction quaJity evaluation purposes, permeability testing was performed on undisturbed

samples obtained from the compacted clay by means of a Shelby tube sampler. One permeability

test on a Shelby tube sample taken from the completed barrier wa11 was required per 10,000 cy.

A minimum of 4 tubes were required to be obtained, and a minimum of two were required to be

tested for permeability. As stated above, less than 15,000 cubic yards were installed, thus, 2 tests

were performed. These undisturbed samples yielded hydraulic conductivity vaJues of 4 x 10-8

cm/sec and 1 x 10-7 cm/sec. This is below the maximum permitted value of 1 x 10-6 cm/sec.

Permeability test results can be found in Attachment 2 of this report

3.2.2 Proctor Testing for Construction Quality Evaluation

As per the CQA plan, a minimum of 1 test per 10,000 cubic yards of clay was required to be

performed. A minimum of 2 moisture/density relationship tests were performed to satisfy this

requirement. Two random samples of clay were colJected from the borrow area and ~brnitted for

proctor testing. These proctors were used to determine the effort required for field compaction.

Maximum proctor densities ranged from 108.8 to 121.2 pcf Optimum moistures ranged from

15.3% to 18.1%. Test results are included under Attachment 2 of this report.

3.2.3 Atterburg Limits for Construction Quality Evaluation

For construction evaJuation purposes during construction of the barrier wall, 1 Atterburg limits

test was required per 5,000 cubic yards of installed clay. A total of 3 tests were performed which

yielded an average Liquid Limit vaJue of 36.9 and Plasticity Index value of 22.5. These values

satisfy the minimum permitted values of 25 and 12 for Liquid Limit and Plasticity Index,

respectively. Atterburg Limits test results can be found in Attachment 2 of this report.

3.2.4 Particle Size Analysis for Construction Quality Evaluation

Particle size distribution via sieve anaJysis and hydrometer testing of the clay was performed

during clay placement. A minimum of one test per 5,000 cubic yards of installed clay was

required to be performed. A total number of 3 sieve analysis tests were performed. These tests

indicated an average percent passing value of 94.6% through a No. 40 and 90.7 percent passing

through a No. 200. Hydrometer testing was performed on one additional sample.

All the grain size analysis results were in compliance with those parameters listed in the CQA Plan

and are included in Attachment 2.

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December 1995

3.2.5 Field Compaction Testing for Construction Quality Evaluation

Field compaction testing was performed as a part of the construction quality evaluation of the

barrier wall. Testing was performed using a field nuclear density gauge in accordance with

applicable safety requirements. CQA requirements for field compaction testing is one test per

10,000 square feet per lift. Considering this requirement, field compaction testing was carried out

progressively with the individual barrier lift placement. Testing was performed at random

locations to provide uniform geographic coverage of the entire area.

The theoretical maximum number of required tests can be calculated based upon the following

assumptions: (1) the maximum number of lifts constructed in any section was 41, (2) the

maximum width of the barrier wall was 15 feet, and (3) the length of the barrier wall was

approximately 1700 feet. These conservative assumptions yield a theoretical number of tests

required of 105. A total number of 193 tests were actually performed. Only 16 areas tested failed

to meet the compaction specification. Failure to meet the specification was believed to be related

to inadequate compactive effort. The insufficient compactive effort and moisture control was -1 l observed to be due to (1) excessively dry conditions in the clay or (2) lack of required

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compactive effort from the compactor. These areas were recompacted in situ, or excavated and

reworked in order to comply with the specifications. Retests were performed in these remedied

areas to confirm that these areas meet the required compaction for clay placement. Field

compaction test results and locations can be found under Attachment 2.

3.2.6 Moisture Content Testing for Construction Quality Evaluation

The construction quality assurance requirement for moisture content testing for the purposes of

material evaluation is one test for every 10,000 square feet per lift. Based on the conservative

assumptions discussed in Section 3 .2.4, at least 105 moisture content tests were required. A total

of 193 tests were performed. Moisture content test results can be found in Attachment 2. Results

of moisture content tests revealed that the quality of clay material obtained on-site was

consistently 0 to 5 points wetter than optimum.

3.3 Conclusion

The Clay Barrier Wall was completed in general accordance with the intent of the plans and

specifications. The project progressed as shown in the photographs (Attachment 3) and as

described in the Daily Reports (Attachment 1 ). All surveying, excavation, clay placement, testing,

construction methods review, and documentation was performed as outlined in the CQA Plan

(Attachment 4), design plans (Attachment 5), and the 1995 Agreed Order.

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CALCULATION OF POTENTIAL GROUNDWATER FLUX FROM YARD 520 TYPE III AREAPINES AREA OF INVESTIGATION

Darcy's Law Equations:1 Approximate location of clay barrier2

K = hydraulic conductivityi = gradientL = lengthb = thickness of aquiferA = cross sectional areaQ = groundwater flux

Flux variables for clay wallVariable Value Units Notes

K3 7.00E-08 cm/sec

K 0.000198 ft/day

b 15 ft

L 2,158 ftA 32,370 ft2

width 3 ft Based on the design requirement, the width of the wall must be at least 3 feet.6

For comparison to groundwater flow from the south, a length of 100 ft is used (to be comparable to the groundwater calculation).

Based on the design requirement, the hydraulic conductivity of the wall must be less than 106 cm/sec.4

The measured, in-place hydraulic conductivity of the barrier wall was 7x10-8 cm/sec.

This value assumes a water table elevation that is equal to the ground surface elevation. It is a conservative estimate.5

LbA =

KAiQ =

1 of 5 December 5, 2008


Approximate ApproximateLocation7 Depth Surface Bottom

Elevation (ft) Elevation (ft)GP009A 20 653 633GP012A 16 647 631GP005 12 652 640GP006 12 656 644

The water table was not encountered in these borings. For this effort, the maximum elevation of the water column will be assumed to be 630 feet. Thus, the maximum change in water table elevation across the clay wall is 25 feet based on the July 2008 sampling round. During this round, water levels in the surrounding aquifer were approximately 605 feet.

Cross Section of Yard 5208



Average measured flow in West Volumetric Budget from the Numerical Model (ft3/day)10

Branch of Brown Ditch at SW0239 In OutQ 2.23 ft3/sec Storage 0 0Q 192,672 ft3/day Constant Head 0 113,582

Drains 0 81,524Minimum measured flow in West Rivers 7,626 208,814Branch of Brown Ditch at SW0239 GHB 25,223 20

Q 0.43 ft3/sec Recharge 371,096 0Q 37,152 ft3/day Total 403,945 403,940

Maximum measured flow in West Branch of Brown Ditch at SW0239

Q 4.85 ft3/secQ 419,040 ft3/day

Ground flow through a hypothetical flow tube from the south, Wells MW-3A and MW11513

between MW115 and MW-3A, 100 ft wideAverage Water Table Elevation (ft)11

MW115 618.03MW-3A 611.62distance 435 ftVariable Value Units

L 100 ftb 15 ftA 1,500 ft2

i 0.0147K12 17.0 ft/dayQ 376 ft3/day



Flux associated with change in head across three foot thick wallHead % Average % Minimum % Maximum % Flow

Difference i Q (ft3/day) Flow Flow Flow Q (ft3/day) of(ft) B. Ditch B. Ditch B. Ditch 100 ft width Groundwater0 0.00 0 0.000% 0.00% 0.000% 0 0.0%2 0.67 4 0.002% 0.01% 0.001% 0 0.1%4 1.33 9 0.004% 0.02% 0.002% 0 0.1%6 2.00 13 0.007% 0.03% 0.003% 1 0.2%8 2.67 17 0.009% 0.05% 0.004% 1 0.2%10 3.33 21 0.011% 0.06% 0.005% 1 0.3%12 4.00 26 0.013% 0.07% 0.006% 1 0.3%14 4.67 30 0.016% 0.08% 0.007% 1 0.4%16 5.33 34 0.018% 0.09% 0.008% 2 0.4%18 6.00 39 0.020% 0.10% 0.009% 2 0.5%20 6.67 43 0.022% 0.12% 0.010% 2 0.5%22 7.33 47 0.024% 0.13% 0.011% 2 0.6%24 8.00 51 0.027% 0.14% 0.012% 2 0.6%26 8.67 56 0.029% 0.15% 0.013% 3 0.7%

Flux from Yard 520 Type III Area

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Head change across three foot thick wall (ft)

Flux

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Notes:1. Fetter, C.W. 2001. Applied Hydrogeology. Upper Saddle River, NJ: Prentice Hall. 4th Ed. pg 82.2. Brown, Inc. 2005. Closure Certification Type III Area - Yard 520. Chicago, IL: Weaver Boos Consultants, Inc.

Brown, Inc. 1991. Construction Quality Assurance Plan: Clay Barrier Wall. Elkhar, In: Weaver Boos Consultants, Inc.3. Weaver Boos. 1995. Yard 520 Solid Fill Site: Clay Barrier Wall CQA Report. pg 4.4. Brown, Inc. 1991. Construction Quality Assurance Plan: Clay Barrier Wall. Elkhar, In: Weaver Boos Consultants, Inc. pg 1.5. Weaver Boos. 1995. Clay Barrier Wall CQA Report: Attachment 5. Generalized Subsurface Profile A-A.6. Weaver Boos. Undated. Request for Alternate Restricted Waste Type Designation: Yard 520 Sold Waste Fill. pg 4.7. ENSR. 2008. Evaluation of Data Collected Under the Yard 520 Sampling and Analysis Plan. Docket No. 01776-028-100a. Attachment A: Yard 520 III

(South) Area Boring Logs.8. Modified from ENSR. 2008. Remedial Investigation Report: Cross Section D-D'. Westford, MA. AOC II - Docket No. V-W-'04-C-784 - RI Report.9. ENSR. 2008. Remedial Investigation Report: Table 2-10. Westford, MA. AOC II - Docket No. V-W-'04-C-784 - RI Report.10. ENSR. 2008. Remedial Investigation Report: Appendix L - Groundwater Model. Westford, MA. AOC II - Docket No. V-W-'04-C-784 - RI Report.11. ENSR. 2008. Remedial Investigation Report: Table 2-8 and Table 3-3. Westford, MA. AOC II - Docket No. V-W-'04-C-784 - RI Report.12. ENSR. 2008. Remedial Investigation Report. Westford, MA. AOC II - Docket No. V-W-'04-C-784 - RI Report. pg. ES2.13. Modified from ENSR. 2008. Remedial Investigation Report: Figure 2-9. Westford, MA. AOC II - Docket No. V-W-'04-C-784 - RI Report.


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