Att_E_GCL_Repair_Work_Plan.pdf

Ann Edwards County Executive

County of Sacramento

Dave Defanti, Deputy County Executive

Community Services

Waste Management and Recycling

Keith Goodrich – Director www.sacgreenteam.com

March 22, 2023

Howard Hold, P.G.

Senior Engineering Geologist Compliance and Enforcement Unit Central Valley Regional Water Quality Control Board 11020 Sun Center Drive #200 Rancho Cordova, CA 95670

WORK PLAN FOR PHASE A COMPOSITE LINER SYSTEM REPAIR

KIEFER LANDFILL, MODULE 4, PHASE 1, SACRAMENTO COUNTY,

CALIFORNIA

This Work Plan provides relevant procedures and details for repair of the composite liner system of Module 4, Phase 1 (M4P1) at Kiefer Landfill. This Work Plan covers the first phase (Phase A) of liner system repairs within M4P1 being addressed after the initial issue was discovered and remediated.

Pursuant to the initial self-reported issue with the liner, the Department of Waste Management and Recycling (DWMR) received a Notice of Violation (NOV), dated February 22, 2023, from the Central Valley Regional Water Quality Control Board (CVRWQCB) for non-compliance with Waste Discharge Requirements (WDRs) Order R5-2016-0013. The NOV requires that the DWMR submit a Work Plan for subsequent repairs by March 23, 2023. In particular, the Work Plan is required to address:

Reestablishment of the integrity of the M4P1 sideslope liner system from the top of the unit to the base (for the identified non-compliant geosynthetic clay liner [GCL] seams).

Methodology to demonstrate that the other side slopes of the Unit are still compliant

Phase A Work Plan

Based upon observations made during the initial repairs performed in January and February pursuant to the originally identified liner damage, the DWMR proposes a Work Plan to investigate the integrity of every seam in the Phase A area and remediate all non-compliant

ATTACHMENT D

occurrences found. While work beyond the Phase A area may be subsequently required, this plan specifically focuses on all seams along the South Slope in the Phase A area which are of first concern, from the originally identified “Panel #18” to the southwest corner. This Work Plan presents the general approach to restore the side-slope composite liner system to the specifications presented in Section D.1.B of the WDRs.

The Phase A Work Plan consists of 8 steps, to investigate and complete any needed repairs.

The steps are described as follows:

1. Excavate and relocate solid waste already in place in M4P1 as necessary to safely expose the operations layer in the Phase A Area.

2. Excavate the side-slope operations/leachate collection and removal system (LCRS) layer to expose the geomembrane above each GCL seam.

3. Cut the geomembrane at to expose the GCL seam and determine if the minimum required seam overlap exists. Document, with photos and survey the discovered condition.

4. On any seam where a deficiency between adjacent GCL panels is determined to exist, cut the geomembrane parallel to the slope, both upslope and downslope, to expose the GCL seam until the minimum required overlap, is observed.

5. Repair and overlap any non-compliant GCL seams with additional GCL material along the entire length of the observed deficiency. Document, with photos, the repair.

6. Repair the overlying geomembrane.

7. Provide protection for the repaired slope by placing the drainage operations layer over the geomembrane where possible, and sandbags where not.

8. Submit Construction Quality Assurance (CQA) documentation to the CVRWQCB.

Step 1: Waste Excavation

The general waste excavation plan for Phase A is shown on Attachment 2. The waste will be excavated at the steepest, safe slope feasible to limit the waste excavation surface area exposed to the atmosphere and to limit the excavation volume. Initially, waste will be excavated at a 2H:1V slope but may be steepened as the excavation progresses if field conditions are determined to warrant. Waste will be excavated to approximately 10 feet vertically above the base initially to provide access to the side slope. Additional waste excavation may be needed to conduct repairs.

Waste will be excavated utilizing an excavator and pushed with a dozer or loaded into trucks for deposition in an area out of the way of the excavation and repair activities. Excavated waste will be compacted and covered with daily cover materials by site operations.

Air monitoring will be performed during the waste excavation and during the liner repair using 4-gas meters to reduce the potential for worker exposure to landfill gases and a hazardous atmosphere. Additionally, air blowers will be used to provide ventilation, if necessary, to ensure a safe atmosphere for all workers within the excavation.

Step 2: Side-Slope Operations/LCRS Layer Excavation

Following waste removal, the side-slope operations/LCRS layer will be carefully excavated above each GCL seam. The side-slope operations/LCRS layer will be excavated using an excavator with a smooth edge bucket to within 4 to 6 inches of the geomembrane to minimize potential damage to the geomembrane. The remaining material will be excavated using hand tools.

Step 3: Geomembrane Window Investigation

At a distance of approximately 40% the length of the slope, when measured from the bottom, a window in the geomembrane will be cut to expose every GCL seam and determine if sufficient seam overlap exists. A minimum in-place seam overlap of 6-inches shall be required to demonstrate sufficiency. The existing condition will be documented, including photos, and the location surveyed.

Where the GCL panel seams are observed to be compliant, no further effort is needed and repairs of the geomembrane will be initiated and described in Step 6. Where sufficient overlap is determined not to exist, the seam shall be deemed “non-compliant” and work shall proceed to the comprehensive remediation as described in Steps 4 through 7.

Step 4: Geomembrane Exposure for Non-compliant Seams

On non-compliant GCL seams, the geomembrane will be cut vertically along the slope so that the extent of the non-compliant GCL seams can be observed, documented, and repaired. .

Step 5: GCL Repairs

The GCL will be repaired in accordance with the M4P1 Construction Documents using material that meets or exceeds the requirements of the M4P1 Technical Specifications. The repair procedures will include:

Cut geomembrane vertically to expose the GCL panel seam.

Inspect and document the condition of the existing GCL material and seam.

Overlap defective GCL area with a strip of GCL. Overlap shall be a minimum of 12 inches in all directions.

Apply granular bentonite to the GCL repair seams at the Manufacturer’s recommended frequency.

Heat bond the GCL patch to the adjacent GCL panels using a hot air hand tool, such as a “Leister” or a torch.

Document, with photos and survey the repairs.

Step 6: Geomembrane Repair

The cut geomembrane will be repaired by welding a patch over the cut area. The geomembrane liner layer will be repaired in accordance with the M4P1 Construction Documents using material that meets or exceeds the requirements of the M4P1 Technical Specifications.

Depending on the size of the repair and available overlap, the geomembrane will be repaired by either fusion welding a new narrow panel at the seam, or by extrusion welding a patch over the cut area. The geomembrane liner layer will be repaired in accordance with the M4P1 construction documents using material that meets or exceeds the requirements of the M4P1 technical specifications, including full CQC and CQA documentation with photos.

Step 7: System Protection

Following repair of the GCL and geomembrane, or demonstration that sufficient GCL overlap exists, the composite liner system will be protected against wind by using a ballasting system.

Where possible, the operations/LCRS layer will be replaced to a minimum thickness of 2 feet.

Where placement of the operations / LCRS layer is not possible to place due to height limitations, sandbag arrays shall be employed to ballast the remainder of the slope.

Step 8: Quality Assurance

Field Quality Control and Quality Assurance shall be in accordance with the M4P1 Construction Documents and CQA Plan. The M4P1 GCL and Geomembrane specifications and the M4P1 CQA Plan are included as Attachment 3 and Attachment 4, respectively.

A third party CQA Consultant, different from the original CQA Consultant, will be retained to perform the CQA work. The CQA Consultant shall observe and document all work associated with the overlap evaluation and the liner repairs in accordance with this Work Plan and the M4P1 Construction Documents. A certification report documenting observations of existing conditions, construction activities, repair materials, a description of significant construction problems and the resolution to these problems, changes to the Work Plan or Technical Specifications and the justifications for these changes, and as-built drawings will be prepared.

The certification report shall be signed and sealed by a civil engineer registered in the State of California, by whom the CQA activities were supervised and work performed in responsible charge.

Attachment 1

Notice of Violation, Module 4 Non-Compliant Composite Liner, Kiefer Road Landfill, Sacramento County

WORK PLAN FOR PHASE A COMPOSITE LINER SYSTEM REPAIR

KIEFER LANDFILL, MODULE 4, PHASE 1, SACRAMENTO COUNTY,

CALIFORNIA

Central Valley Regional Water Quality Control Board 22 February 2023

Brian Liebich, P.E.

Principal Civil Engineer County of Sacramento Department of Waste Management & Recycling 9850 Goethe Road Sacramento, CA 95827

NOTICE OF VIOLATION, MODULE 4 NON-COMPLIANT COMPOSITE LINER, KIEFER

ROAD LANDFILL, SACRAMENTO COUNTY

The Kiefer Road Landfill is owned and operated by Sacramento County Department of Waste Management and Recycling (hereafter Discharger). The Kiefer Road Landfill is regulated under Waste Discharge Requirements (WDRs) Order R5-2016-0013.

On 24 December 2022, Kiefer Landfill Operations staff was preparing the Module 4, Phase 1, south slope operations layer and inadvertently damaged the primary geomembrane liner system (initial repair site) with heavy equipment. During the initial repair investigation on 6 January 2023, the damaged geomembrane was removed, the damaged GCL was removed, and the GCL seam running upslope from the initial repair site was observed to be separated approximately 9 to 12 inches. According to the Discharger, the GCL panel west of the separation was noted as “folded” and “bunched”. No other folding or bunched GCL were observed during the 6 January 2023 investigation. The GCL damaged was replaced with dry GCL material, and the geomembrane was patched, welded, and tested in accordance with Module 4, Phase 1 construction specifications. Further work to investigate the GCL separation was scheduled for a later date.

On 12 January 2023 the GCL investigation ran from the top of the initial repair to the top of slope. The Discharger cut the geomembrane approximately 100 feet to expose the GCL. The underlying GCL was observed to be separated from top to bottom. The Discharger patched the separated panels using a four (4) foot wide GCL patch. This provided a 12-inch overlap in all directions. The Discharger placed granular bentonite and heat bonded the seams to existing GCL panels. The geomembrane was patched with a two (2) foot wide 60 mil HDPE liner which were welded to seal the repair. All materials met conformance standards described in previously approved Construction Quality Assurance Plans.

The Discharger attempted to identify the GCL separation downslope of the initial repair site by removing the in-place operations layer down to the geomembrane. The Discharger cut the geomembrane to expose the GCL, which was observed to be separated by approximately 12-inches between panels. The Discharger discontinued the downslope investigation due to existing waste column and the concern of further damage to the liner. The exposed GCL and geomembrane were repaired in accordance with Module 4, Phase 1 construction specifications.

Kiefer Road Landfill - 2 - 22 February 2023

Notice of Violation

Based on documents submitted by the Discharger1 and verbal conversations with staff, the Discharger remains out of compliance with Construction Specifications, Section D.1.b., and Construction Specifications D.6. Since the GCL has been observed to be separated downslope of the initial repair site, Module 4, Phase 1 side slope no longer meets the conditions of the approved engineered alternative of the side slope liner system outlined in the WDRs. The GCL separation between panels conflicts with the standards and specifications outlined in Section F of the 2015 Standard Provisions and Reporting Requirements.

Until the side slope liner is restored to the specifications presented in Construction Specifications, Section D.1.b., of the WDRs, the Discharger will be in violation of those requirements. Therefore, no later than 23 March 2023, the Discharger shall compile the necessary engineering data, photographs, engineering calculations and engineering drawings to support a plan for re-establishing the integrity of the sidewall liner system from the top of the unit to the base of the unit. This plan shall also propose a methodology to demonstrate that the other side slope seams of the Unit are still compliant with the WDRs engineered alternative.

Please include a detailed schedule of all proposed work. Upon submittal and review of the submitted, Regional Board staff will review and determine if additional actions will be required by the Discharger to return compliance with the WDRs.

The compliance and enforcement unit appreciates your effort to remedy the problem. If you have any questions or would like to schedule a meeting, please contact Todd Del Frate by phone at 916-464-4737 or by email at todd.delfrate@waterboards.ca.gov.

HOWARD HOLD, P.G.

Senior Engineering Geologist Compliance and Enforcement Unit

Cc: Katie Miller, Sacramento County Environmental Health Rachel Beck, CalRecycle Brad Shelton, Central Valley Regional Water Quality Control Board Rob Busby, Central Valley Regional Water Quality Control Board Rachel Davis, Kiefer Road Landfill

CIWQS VID #113105

1 The observation of the GCL separation is documented in the Construction Quality Assurance Report dated 19 January 2023, which was prepared by Geologic Associates (Jacob Russell, Professional Civil Engineer #64512).

mailto:todd.delfrate@waterboards.ca.gov

Kiefer Road Landfill - 3 - 16 February 2023

Attachment 2

Phase A Waste Excavation

Attachment 3

M4P1 GCL and Geomembrane Specifications

Kiefer Landfill Module 4, Phase 1 Base Liner System DIVISION 2 - SITEWORK

Geo-Logic Associates Section 02778 August 2019, Revision 1 Page 1 of 30 HDPE GEOMEMBRANE

SECTION 02778

HDPE GEOMEMBRANE

PART 1 GENERAL

1.1 SUMMARY

A. Section includes furnishing and installing the 60-mil single sided and double-sided textured HDPE geomembrane for the composite liner system in accordance with the Specifications and the Construction Drawings.

1.2 Related Sections:

A. Section 02200 — Site Earthwork.

B. Section 02771 – Geotextile.

C. Section 02774 – Geocomposite.

D. Section 02779 – Geosynthetic Clay Liner (GCL).

1.3 REFERENCES

A. ASTM International, latest version:

1. ASTM D638 - Standard Test Method for Tensile Properties of Plastics.

2. ASTM D1004 - Standard Test Method for Tear Resistance (Graves Tear) of Plastic Film and Sheeting.

3. ASTM D1238 - Standard Test Method for Melt Flow Rates of Thermoplastics by Extrusion Plastometer.

4. ASTM D1505 - Standard Test Method for Density of Plastics by the Density Gradient Technique.

5. ASTM D1603 - Standard Test Method for Carbon Black Content in Olefin Plastics.

6. ASTM D3895 - Standard Test Method for Oxidative Induction Time of Polyolefins by Differential Scanning Calorimetry.

7. ASTM D4218 - Standard Test Method for Determination of Carbon Black Content in Polyethylene Compounds by the Muffle Furnace Technique.

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8. ASTM D4437 - Standard Practice for Non-destructive Testing (NDT) for Determining the Integrity of Seams Used in Joining Flexible Polymeric Sheet Geomembranes.

9. ASTM D4759 - Standard Practice for Determining the Specification Conformance of Geosynthetics.

10. ASTM D4833 / D4833M - Standard Test Method for Index Puncture Resistance of Geomembranes and Related Products.

11. ASTM D5321 / D5321M - Standard Test Method for Determining the Shear Strength of Soil-Geosynthetic and Geosynthetic-Geosynthetic Interfaces by Direct Shear.

12. ASTM D5397 - Standard Test Method for Evaluation of Stress Crack Resistance of Polyolefin Geomembranes Using Notched Constant Tensile Load Test.

13. ASTM D5596 - Standard Test Method for Microscopic Evaluation of the Dispersion of Carbon Black in Polyolefin Geosynthetics.

14. ASTM D5721 - Standard Practice for Air Oven Aging of Polyolefin Geomembranes.

15. ASTM D5885 - Standard Test Method for Oxidative Induction Time of Polyolefin Geosynthetics by High Pressure Differential Scanning Calorimetry.

16. ASTM D5994 - Standard Test Method for Measuring Core Thickness of Textured Geomembrane.

17. ASTM D6365 - Standard Practice for the Nondestructive Testing of Geomembrane Seams using the Spark Test.

18. ASTM D6392 - Standard Test Method for Determining the Integrity of Nonreinforced Geomembrane Seams Produced Using Thermo Fusion Methods.

19. ASTM D6243 / D6243M – Standard Test Method for Determining the Internal and Interface Shear Strength of Geosynthetic Clay Liner by the Direct Shear Method.

20. ASTM D6693 - Standard Test Method for Determining Tensile Properties of Non-reinforced Polyethylene and Non-reinforced Flexible Polypropylene Geomembranes.

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21. ASTM D7238 - Standard Test Method for Effect of Exposure of Unreinforced Polyolefin Geomembrane Using Fluorescent UV Condensation Apparatus.

22. ASTM D7466 - Standard Test Method for Measuring the Asperity Height of Textured Geomembrane.

B. Geosynthetic Institute (GSI):

1. GM6 - Pressurized Air Channel Test for Dual Seamed Geomembranes.

2. GM13 - Test Methods, Properties and Testing Frequency for High Density Polyethylene (HDPE) Smooth and Textured Geomembranes.

3. GM19 - Seam Strength and Related Properties of Thermally Bonded Polyolefin Geomembranes.

1.4 DEFINITIONS

A. Batch: A quantity of resin, usually the capacity of one rail car, used in the fabrication of high density polyethylene (HDPE) geomembrane sheet. The finished sheet will be identified by a roll number corresponding to the particular quantity of resin used.

B. Bridging: The condition when geomembrane becomes suspended over its subgrade due to contraction of the material or poor installation.

C. Construction Quality Assurance (CQA) Consultant: The party, independent from Manufacturer or Installer that is responsible for observing and documenting activities related to the quality assurance of production and installation of the geosynthetic components of the lining system.

D. Construction Quality Assurance (CQA) Laboratory: The party, independent from the Owner, Manufacturer, Fabricator, and Installer, responsible for conducting tests on samples of geosynthetics obtained at the site.

E. Construction Quality Assurance (CQA) Monitor: The site representative of the CQA Consultant.

F. Extrudate: The molten polymer which is emitted from an extruder during seaming using either extrusion fillet or extrusion flat methods. The polymer is initially in the form of a ribbon rod, bead or pellets.

G. Geomembrane Manufacturer: The party responsible for the production of the geomembrane rolls from resin and for the quality of the resin.

Geo-Logic Associates Section 02778 August 2019, Revision 1 Page 4 of 30 HDPE GEOMEMBRANE

H. Geomembrane: An essentially impermeable membrane used as a solid or liquid barrier. Synonymous term for flexible membrane liner (FML).

I. Geomembrane Subsurface: The soil or geosynthetic surface on which the geomembrane lies.

J. Installer: The party responsible for field handling, transporting, storing, deploying, seaming, temporary restraining (against wind), and installation of the geomembrane.

K. Panel: The unit area of geomembrane that will be seamed in the field. A panel is identified as a roll or portion of a roll without any seams.

1.5 SUBMITTALS

A. The Contractor shall identify the Geomembrane Manufacturer and Installer, and shall furnish the following Installer qualifications in accord with the appropriate Section:

1. Installer approval by Manufacturer.

2. Installer qualifications.

3. Personnel qualifications.

B. The Contractor shall submit the following Quality Control Documents and warranty information at the times indicated:

1. Manufacturer’s Quality Control Manual after Notice of Award.

2. Samples of Manufacturer’s material warranty and installation warranty from the Contractor after the Notice of Award.

3. Certificate of Acceptance of Geomembrane Subgrade by Contractor for each area to be covered by the geomembrane, signed by the installation supervisor, prior to the start of installation (beginning installation shall mean acceptance and approval of existing subsurface condition).

4. Quality control documentation prepared during installation, within fifteen (15) calendar days following partial completions during on-going construction.

C. The Contractor shall submit the following Manufacturer data to the CQA Officer and Engineer in accordance with Section 01300 – Submittals. The Contractor shall obtain the CQA Officer’s acceptance of applicable submittals before material shipment.

Geo-Logic Associates Section 02778 August 2019, Revision 1 Page 5 of 30 HDPE GEOMEMBRANE

1. Resin Data:

a. Statement of production date or dates.

b. Certification stating that resin meets Specification requirements.

c. Certification stating all resin is from the same resin supplier and is of one resin type.

d. Copy of quality control certificates issued by the resin supplier.

e. Test reports from resin supplier.

f. Laboratory test results and certification stating resin meets the Specification requirements presented in Table 02778-1.

2. Geomembrane:

a. Statement of production date or dates.

b. Laboratory test results and certification stating geomembrane meets the Specification requirements presented in Table 02778-2.

c. Certification stating all geomembrane is furnished by one Manufacturer, and all geomembrane is manufactured from one resin type obtained from one resin supplier.

d. Statement certifying that no reclaimed polymer is added to resin (other than up to 10 percent reworked geomembrane material). If reclaimed polymer is used, it must be from a similar HDPE resin as the parent material.

e. Geomembrane delivery, storage, handling, and installation instructions.

f. Provide representative samples of the geomembrane to be used for interface strength testing presented in Tables 02778-3 and Table 02778-4. Interface strength testing will be performed by the CQA Laboratory prior to final approval of the geomembrane material. Submitted geomembrane samples shall be a minimum of 1 foot by 1 foot square and come from material subjected to the other required conformance tests produced specifically for this project.

Geo-Logic Associates Section 02778 August 2019, Revision 1 Page 6 of 30 HDPE GEOMEMBRANE

TABLE 02778-1

PROPERTIES FOR HDPE RESIN

PROPERTY TEST

DESIGNATION

TEST

REQUIREMENTS(1) FREQUENCY

Density ASTM D1505 0.932 g/cm3 1 per Resin Lot (i.e. Batch, Railcar)

Melt Flow Index ASTM D1238 Condition E

1 g/10 minutes maximum

1 per Resin Lot (i.e. Batch, Railcar)

Note: 1 Tests are to be conducted on natural resin prior to the addition of carbon black or other color additive.

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TABLE 02778-2

PROPERTIES FOR SINGLE AND DOUBLE SIDED TEXTURED HDPE GEOMEMBRANE

PROPERTY TEST

DESIGNATION

ACCEPTANCE

VALUE

MQC

TESTING

FREQUENCY

Average Thickness (min)1

Lowest Individual Thickness1

ASTM D5994 60 mil 55 mil

Each Roll Each Roll

Asperity Height, mils2 ASTM D7466 Minimum 20 mils average measurement and as needed to meet shear strength requirements

Every 2nd Roll (Both Sides

Tested)

Density (min avg.), g/cm3 ASTM D1505 0.940 200,000 lb

Tensile Properties (min avg.) both directions ASTM D6693, Type

IV

• Yield strength (min.) 126 lb/in-width

20,000 lb

• Break strength (min.) 90 lb/in-width 20,000 lb

• Yield elongation (min.) 1.3” GL 12% 20,000 lb

• Break elongation (min.) 2.0” GL 100% 20,000 lb

Tear Resistance (min avg.) ASTM D1004, Die C 42 lb 45,000 lb

Puncture Resistance (min avg.) ASTM D4833/ D4833M 120 lb 45,000 lb

Carbon Black Content (range) 3, 4 ASTM D4218 2.0-3.0% 20,000 lb

Carbon Black Dispersion ASTM D5596 Note 5 45,000 lb

SP-NCTL, (5 specimens9 ) (minimum) ASTM D5397 300 hrs Each Resin Lot

Oxidative Induction Time (OIT) (min avg) 6

Standard OIT ASTM D3895 100 minutes 200,000 lb

Or

High Pressure OIT ASTM D5885 400 minutes 200,000 lb

Oven Aging at 85 deg. C for 90 days (min avg), 6 ASTM D5721 Each Formulation

Standard OIT ASTM D3895 55 %

Or

High Pressure OIT ASTM D5885 80 %

UV Resistance retained after 1,600 hrs 7 ASTM D7238 Each Formulation

High Pressure OIT (min avg) .8 ASTM D5885 50 %

Geo-Logic Associates Section 02778 August 2019, Revision 1 Page 8 of 30 HDPE GEOMEMBRANE

Notes:

1. The results obtained from D5994 shall be an average of all readings taken; this result must meet or exceed the specified value for minimum average thickness. In addition, all individual readings taken to obtain the average cannot be less the specified average thickness requirement.

2. Of 10 readings, 8 out of 10 must be a minimum 18 mils, and the lowest individual ready must be 15 mils. Each side shall be tested for each sample taken from double sided textured geomembrane.

3. Other methods such as D1603 (tube furnace) or D6370 (TGA) are acceptable if an appropriate correlation to D4218 (muffle furnace) can be established.

4. Carbon black content is only measured on the black backing of the white-surfaced geomembrane, if applicable. Prior to measuring the carbon black content, the white surface shall be scrapped or ground off to avoid misrepresentative results in the final result. Contact the manufacturer for an approved method of testing.

5. Carbon black dispersion for 10 different views: All 10 in Categories 1 or 2.

6. The manufacturer has the option to select either of the OIT methods listed to evaluate the antioxidant content in the geomembrane.

7. The condition of the test shall be 20-hr. UV cycle at 75 deg. C followed by 4-hr. condensation at 60 deg. C.

8. UV resistance is based on percent retained value regardless of the original HP-OIT value.

9. All specimens shall meet the requirements as shown.

TABLE 02778-3

INTERFACE PROPERTIES1,3,4,5,6,7,8,9,10,11,12,13,14,15,16

BASE DOUBLE COMPOSITE LINER

NORMAL LOAD

(PSF)

REQUIRED SHEAR STRENGTH

(MINIMUM) (PSF)

5,000 900

10,000 1,750

15,000 2,525

20,000 3,200

TABLE 02778-4

INTERFACE PROPERTIES2,3,4,5,9,10,12,13,14,15,16

SIDE SLOPE COMPOSITE LINER

NORMAL LOAD

(PSF)

REQUIRED SHEAR STRENGTH

(MINIMUM) (PSF)

5,000 900

10,000 1,750

15,000 2,525

20,000 3,200

Geo-Logic Associates Section 02778 August 2019, Revision 1 Page 9 of 30 HDPE GEOMEMBRANE

Notes for Tables 02778-3 and 02778-4:

1. The composite base liner shear strength shall meet the interface strength requirements of Table 02778-3 and tested at a frequency of one set of tests per test configuration (5 sets of tests, with each set tested under different normal loads as specified) using the following procedures::

a. The interface testing shall be component-based. Therefore, representative samples of the base composite liner system shall be tested as follows:

i. 12-oz cushion geotextile against textured 60-mil HDPE geomembrane

ii. Textured 60-mil HDPE geomembrane against heat burnished side of GCL

iii. Non-heat burnished side of GLC against geocomposite

iv. Geocomposite against textured 60-mil HDPE geomembrane

v. Non-heat burnished side of GCL against foundation soil

2. The composite side slope liner shear testing configuration shall be used with testing as a multi-component or

“sandwich” for:

a. Side Slope Composite Liner: Operations soil (loosely tamped in place) / 60-mil single-sided-textured HDPE geomembrane (textured side down against GCL) / hydrated GCL (heat burnished side against textured geomembrane) / foundation layer

3. Compact the foundation layer soil to 90 percent relative compaction and 2 percent above the optimum moisture content per ASTM D1557.

4. Measure and report asperity height of geomembrane (both sides for double-sided-textured geomembrane), moisture content of GCL before and after the test, and peel strength of GCL.

5. Test the sample configurations according to ASTM D5321 or D6243 under normal loads shown in Table 02778-3 using properly calibrated equipment. The specified loads shall be used as consolidation loading.

6. The tests against the GCL material shall be set up with the geomembrane clamped to the upper box and the GCL securely clamped in the bottom box of the direct shear apparatus with the non-woven geotextile in contact with the geomembrane.

7. The geomembrane shall be supported in the box using a rigid substrate with the contact unit consisting of a truss plate or other high friction grip plate approved by the ENGINEER.

8. The geocomposite and GCL to be tested in contact with the geomembrane shall be supported in the box using a rigid substrate with the contact unit consisting of a truss plate or other high friction grip plate approved by the ENGINEER.

9. Hydrate GCL separately at 10 psi normal load for a minimum of 48 hours. Apply normal load first and then start soaking.

10. Once GCL is hydrated and sample configured and loaded to the corresponding normal stress, allow sample to consolidate at least 48 hours or until t90

11. Interface tests of geomembrane against cushion geotextile and geocomposite shall be completed in a “flooded” or wet condition.

12. Apply the test normal load at 1,000 lbs. / minute.

13. Shear at 0.04 inches / minute.

14. Minimum specified post peak strengths (at 3 inches deformation) or the lower value between peak and the strength at 3 inches deformation.

15. At the completion of the test, the third party laboratory shall photograph and record the location where shearing occurred, and the general conditions of the samples.

16. The results of the test shall be reported in graphical and tabular forms including:

a. Shear force versus shear displacement curves for all design normal loads.

b. Peak and large displacement (i.e. at 3 inches shear displacement) shear strengths.

Geo-Logic Associates Section 02778 August 2019, Revision 1 Page 10 of 30 HDPE GEOMEMBRANE

c. Friction angle and adhesion determined from the best fits to peak and post-peak shear strengths versus normal stress curves.

d. Friction angles determined as the secant to the specified normal stress point on the actual peak and the post-peak shear strength versus normal stress curves.

3. Welding Extrudate:

a. Production date or dates.

b. Manufacturer’s certification stating that the welding extrudate is of the same resin type and formulation as the geomembrane.

c. Manufacturer’s quality control test results for the welding extrudate supplied and used for this project.

D. The Contractor shall submit the following schedule and drawings to the CQA Officer for review in accordance with Section 01300 – Submittals. The Contractor shall obtain the CQA Officer’s acceptance of applicable submittals before geomembrane shipment.

1. An installation schedule that shall include working days, hours to be worked per day, week and per shift. Indicate any weather delay built into schedule.

2. Proposed Panel Layout Drawings that, once approved, shall be the basis for installing the geomembrane. Approved layout drawing shall be submitted to the CQA Officer in AutoCAD and PDF formats.

E. Submit the following equipment and personnel information 7 calendar days prior to installation:

1. Equipment list stating quantity and types to be used.

2. List of personnel assigned to perform the seaming operations.

F. Submit to the Engineer and CQA Officer within 15 calendar days following installation completion:

1. Certificate stating the geomembrane has been installed in accordance with the Contract Documents.

2. Manufacturer’s material warranty and the Contractor’s installation warranty.

3. Record Drawings showing measured locations of panels, seams, repairs, patches, and destructive samples. Record Drawings shall be prepared in

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4. Contractor shall provide copies of test results conducted to the CQA Officer.

1.6 QUALIFICATIONS

A. Installer shall be approved by the geomembrane Manufacturer.

1. Company Qualifications:

a. The installation company shall have worked in a similar capacity on at least five projects similar in complexity to the Project described in the Contract Documents with each of those projects at least 500,000 square feet in size.

b. The installation company shall have installed a minimum of 10 million square feet of polyethylene geomembrane.

2. Personnel Qualifications:

a. Installation supervisor/field engineer shall have worked in a similar capacity on at least two jobs similar in size and complexity to the project described in the Contract Documents.

b. The master seamer shall have completed a minimum of 5,000,000 square feet of geomembrane seaming work using the type of seaming apparatus proposed for use on this Project.

c. Other seamers shall have seamed a minimum of 1,000,000 square feet of geomembrane.

1.7 QUALITY CONTROL

A. The number of resin lots utilized in the production of the geomembrane must be minimized (i.e. resin lot associated with the geomembrane contains a minimum of 40 rolls of finished product).

B. The Contractor/Installer shall not charge any time or material expenses, related to a plant visit by the CQA Consultant to visit the plant during manufacturing.

C. Render assistance as necessary for CQA Consultant to collect product samples.

1.8 DELIVERY, STORAGE, AND HANDLING

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A. Conform to the manufacturer’s requirements to prevent damage to geomembrane.

B. Delivery:

1. Materials shall be delivered to the site only after the CQA Consultant accepts required submittals, conformance testing results, and the interface strength test results.

2. Delivery of rolls shall be made using open flatbed trucks.

3. Manufacturer shall provide unloading straps with the rolls delivered to the site.

4. Damaged geomembrane shall be separated from undamaged geomembrane and each shall be stored at locations designated by the CQA Monitor until proper disposition of material is determined by CQA Officer.

5. The CQA Officer shall be the final authority regarding damage.

6. Deliver in rolls, do not fold.

7. Geomembrane delivered without proper documentation shall be stored separately until documentation is received and accepted by CQA Consultant.

8. The Geosynthetic Inventory Received Log shall be completed by the CQA Monitor during geomembrane delivery.

C. On-Site Storage:

1. The geomembrane shall be stored within the Contractors staging area or as otherwise designated by the Engineer.

2. The geomembrane shall be protected from puncture, dirt, grease, water, moisture, mud, mechanical abrasions, excessive heat, or other damage.

3. The geomembrane shall be stored on a prepared level surface, but not on wooden pallets.

4. The rolls of geomembrane may be stacked per manufacturer’s recommendation but shall not exceed three rolls in height.

D. On-Site Handling:

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1. Use appropriate handling equipment to load, move, or deploy geomembrane from rolls. Appropriate handling equipment includes cloth chokers and spreader bar for loading, and spreader and roll bars for deployment. Dragging panels on ground surface shall not be permitted.

2. Do not fold geomembrane; folded geomembrane shall be rejected.

3. Contractor shall be responsible for pick-up and transporting of material from storage area to work area.

E. Damaged Geomembrane:

1. Geomembrane damage shall be documented by the CQA Monitor and Contractor/Installer.

2. Damaged geomembrane shall be repaired, if possible, in accordance with these Specifications or shall be replaced at no cost.

1.9 WEATHER CONDITIONS

A. Geomembrane shall not be deployed when:

1. The ambient air temperature is above 104 degrees Fahrenheit ( F) or below 40 F, measured 6 inches above the geomembrane surface.

Deployment may be acceptable during prevailing warmer or colder weather conditions if the provisions for seaming, sampling, and testing per Part 3 of this section can be satisfied, and approval is received from the CQA Officer.

2. During precipitation.

3. In the presence of excessive moisture (fog, dew, mist, etc.).

4. In areas of ponded water.

5. In the presence of excessive winds (sufficient to lift panels and prohibit efficient placement of the panels).

1.10 INSTALLATION WARRANTY

A. Installation: Prior to installation, Submit manufacturers and installers written warranty against product and installation defects. Limits of liability must be accepted by the County.

B. Provide a minimum of 2 years non-prorated warranty for the installation against defects.

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PART 2 PRODUCTS

2.1 GENERAL

A. The resin used in the production of the geomembrane material shall be HDPE, new, first quality, compounded and manufactured specifically for producing HDPE geomembrane. Resin types shall not be intermixed.

B. The geomembrane shall be nominal 60-mil-thick textured geomembrane (single and double sided) via blown film, coextruded, or microspiked HDPE as shown on the Construction Drawings and shall meet the latest requirements of GRI GM13 except where modified by this Specification. In addition, the Manufacturer’s Quality Assurance Laboratory must be GAI-LAP Accredited. Geomembrane resin material shall meet the requirements of Table 02778-1. Geomembrane shall meet the requirements of Table 02778-2.

C. Materials used shall be produced in North America. Material from other sources may be used with prior written approval by the Engineer or CQA Officer.

D. Geomembrane shall be supplied in rolls, free of holes, pinholes, bubbles, blisters, excessive gels, undispersed resins, contamination by foreign matter, and nicks and cuts on roll edges. Each roll shall be identified with labels indicating at minimum: identification number, nominal thickness, length, width, manufacturer, and plant location.

E. All additives for UV protection, thermal stability, color, texturing, or processing agents must not “bloom” to the surface over time or inhibit welding.

F. The geomembrane and composite liner system shall meet the interface shear strength requirements of Table 02778-3 and Table 02778-4.

G. Welding Extrudate:

1. Extrudate used to produce extrusion welds shall be made from same resin type and formulation as the geomembrane.

2. Extrudate shall be free of contamination by moisture or foreign matter.

2.2 MANUFACTURER SOURCE QUALITY CONTROL

A. Resin:

1. Do not use post-consumer recycled materials in manufacturing.

Reworked material from manufacturing of geomembrane such as edge trim can be used up to a maximum of 10 percent of the final product.

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2. Resin material shall meet the requirements of Table 02778-1. The properties shall be verified by the geomembrane manufacturer prior to utilizing the resin in manufacturing.

B. Geomembrane:

1. The geomembrane shall meet the minimum requirements of the latest version of GRI GM13 and as modified in Table 02778-2. These properties shall be verified by the geomembrane manufacturer.

2.3 EQUIPMENT

A. Welding equipment and accessories shall meet the following requirements:

1. Equipped with gauges showing temperatures both in the apparatus and at the nozzle (extrusion welder) or at the wedge (wedge welder).

2. Maintained in adequate number to avoid delaying work.

3. Supplied by a power source capable of providing constant voltage under a combined-line load.

4. Provided with splash pad large enough to catch spilled fuel under an electric generator where operating over the liner system.

B. Tensiometers, capable of quantitatively measuring geomembrane seam strength, shall meet the following requirements:

1. Equipped with a gauge accurate to ± 2 pounds per inch (ppi) of geomembrane seam width.

2. Provided with required dies.

PART 3 EXECUTION

3.1 SURFACE CONDITIONS

A. Examine the areas and conditions under which work of this Section shall be performed. Correct conditions detrimental to timely and proper completion of the Work. Notify the CQA Consultant of such conditions and proposed corrective actions before correcting unsatisfactory conditions. Do not proceed until unsatisfactory conditions are corrected.

3.2 PREPARATION

A. Damage to geomembrane subsurface during geomembrane deployment or other activities shall be repaired prior to installation.

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B. Beginning installation shall mean acceptance and approval by the Installer of the existing subsurface condition.

3.3 DEPLOYMENT

A. It is the Installer’s responsibility that each panel deployed shall be assigned a simple and logical identifying code consistent with the submitted proposed panel layout drawings. The coding system shall be subject to approval by the CQA Monitor.

B. No more panels shall be deployed in 1 day than can be welded during that same day. Tack welding may be acceptable as a temporary measure with CQA Monitor’s approval.

C. Geomembrane shall be visually inspected during deployment for imperfections and faulty or suspect areas shall be marked for repair. At the CQA Consultant’s discretion, geomembrane areas requiring more than one repair per 5,000 square feet shall be removed and replaced at no cost to the County.

D. Deployment of the geomembrane shall conform to the following requirements:

1. Repair damage to subsurface or GCL prior to deployment of geomembrane. All foreign substances on the surface of the GCL shall be removed prior to deployment of geomembrane.

2. Geomembrane panels shall be unrolled using methods that shall not damage, stretch, or crimp the geomembrane and shall protect the underlying subsurface from damage.

3. Ballast, that shall not damage the geomembrane, shall be used to prevent uplift due to wind.

4. Methods used shall minimize wrinkles.

5. Personnel walking on the geomembrane shall not engage in activities or wear types of shoes that could damage the geomembrane. Smoking shall not be permitted while working on the geomembrane.

6. Contractor shall not allow vehicle traffic on geomembrane surface, with the exception of an approved ATV used for material deployment after CQA Officer approval. Other vehicle and equipment restrictions for travel on the geomembrane shall conform to limitations shown in Table 02200- 1.

7. Equipment shall not damage the geomembrane by handling, trafficking, leakage of hydrocarbons, or any other means. Geomembrane shall be

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8. Geomembrane folds shall be removed by cutting out folded material and repairing in accordance with Section 3.6, or by pulling on the geomembrane sheet adjacent to the fold. All geomembrane folds that excessively crimp or damage the material shall be cut out and repaired.

E. Sufficient material shall be provided to allow for geomembrane shrinkage and contraction.

F. It is the Contractor’s and Installer’s responsibility to take necessary measures to prevent excess condensation on the geomembrane from adversely impacting the subsurface.

G. Geomembrane must be deployed to completely cover GCL at the end of each day.

3.4 SEAMING

A. Seams shall meet the following requirements:

1. Seams shall be oriented perpendicular to the line of the slope crest (i.e. down and not across slope).

2. Number of seams in corners, odd-shaped geometric locations, and outside corners shall be minimized.

3. No horizontal seams shall be allowed on slopes steeper than 10 horizontal to 1 vertical (10H:1V). Seams perpendicular to slopes greater than 10H:1V shall be located on flat areas at least 5 feet away from the crest or toe of the slope.

4. Seam coding system shall be compatible with panel coding system established in accordance with Article 3.3 of this Specification.

5. If seaming with a wedge welder, panels shall be shingled on all gradients such that the overlapping panel is upgradient of the underlying panel.

B. During Welding Operations:

1. At least one Master Seamer, meeting the qualifications requirements specified in Article 1.6 shall be present.

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2. Other welders, meeting the qualification requirements specified in the Article 1.6, shall be provided in adequate number to avoid delaying work.

3. The Master Welder shall provide direct supervision over other welders.

C. Test Welds:

1. Test welds shall be performed on geomembrane samples to verify welding equipment operations and performance of seaming methods and conditions.

2. No welding equipment or welder shall be allowed to perform production welds until equipment and welders have successfully completed a test weld.

3. Frequency of Test Welds:

a. Minimum of two test welds per day or shift for each welding apparatus and each technician utilizing the equipment, shall be made: one made prior to the start of work and one completed at mid shift. If equipment is shut down for longer than 1 hour an additional trial weld shall be performed.

b. Additional test welds shall be performed when requested by the CQA Monitor.

4. Test welds shall be made under the same surface and environmental conditions as the production welds (i.e. in contact with geomembrane subsurface and similar ambient temperature).

5. Each test weld sample shall be at least 3 feet long and 12 inches wide with the seam centered lengthwise.

6. Two, 1 inch wide test strips shall be cut from opposite ends of the trial weld (total of four). Two specimens shall be tested for peel strength and peel separation, and two specimens tested for shear strength utilizing the procedures outlined in ASTM D6392. Results of tests performed on the trial weld specimens shall conform to the latest version of GRI GM19 Table 1(a) for 60 mil HDPE geomembrane. The requirements are summarized in Table 02778-5:

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TABLE 02778-5

PROPERTIES FOR HDPE TEST WELDS

PROPERTY TEST

DESIGNATION TEST REQUIREMENT 3

Wedge Weld 1, 2:

Peel Strength Peel Separation Shear Strength

ASTM D6392

91 lb/in 25 %

120 lb/in

Extrusion Weld 2:

Peel Strength Peel Separation

78 lb/in 25 %

120 lb/in

Notes:

1. Both tracks of the wedge weld shall be tested for peel properties.

2. 2 of 2 specimens must pass all criteria.

3. Acceptable break (failure) codes per the description outlined in ASTM D6392-12 are:

Wedge Weld = AD and AD-Brk <25 % Extrusion Weld = AD1, AD2 and AD-WLD (as long as strength is achieved)

7. The test weld shall be repeated, in its entirety, when any of the test weld samples fail in either peel or shear.

8. When repeated test welds fail, the tested welding apparatus and welder shall not be used for welding until the reason for the failing tests is identified and corrected. A passing test weld shall be performed following correction.

D. Install geomembrane using the following general seaming procedures:

1. The surface of the geomembrane shall be clean of grease, moisture, dust, dirt, debris, or other foreign material.

2. Panels shall overlap by a minimum of 3 inches for extrusion and 4 inches for hot-wedge welds unless otherwise approved by the CQA Monitor.

3. Solvents or adhesives shall not be used unless the product is approved in writing by the CQA Officer.

4. Adequate material shall be provided to allow peel testing of both sides of a double-wedge weld.

E. The Installer shall extend welds to the outside edge of panels placed under anchor berms or in anchor trenches.

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F. If required, the Installer shall be responsible for providing a firm subsurface by using a flat board, a conveyor belt, or similar hard surface directly under the seam overlap to achieve adequate support during seaming operations.

G. Adequate lighting shall be provided if seaming operations are carried out at night.

H. Fishmouths or wrinkles at seam overlaps shall be cut to achieve a flat overlap.

The cut fishmouths or wrinkles shall be extrusion welded or patched where the overlap is more than 3 inches. When there is less than 3 inches overlap, an oval or round patch extending a minimum of 6 inches beyond the cut in each direction shall be used.

I. The Installer Quality Control (QC) Technician shall log every 2 hours:

1. Temperature on the geomembrane surface.

2. Extrudate temperatures in barrel and at nozzle (extrusion welder).

3. Operating temperature of hot wedge (hot-wedge welder)

4. Preheat temperature.

J. Ambient temperature, measured 6 inches above geomembrane surface, shall be logged every 2 hours. Geomembrane shall be deployed between ambient temperatures of 40 F to 104 F and when the relative humidity is less than 80 percent, unless other limits are approved, in writing, by the CQA Officer.

Deployment of geomembrane below 40 F shall only be allowed after it has been verified that the material can be seamed according to these Technical Specifications, and is approved by the CQA Officer.