LINER AND COVER CONSTRUCTION BASICS

Presented by:

Curt Ahrendsen, Principal

American Environmental Consulting

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Construction Requirements and Controls Are Related To:

• Applicable Regulations

• Approved Engineering Design Plan

• Approved Construction Quality Assurance Plan

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Applicable CDPHE Regulations

WHILE THERE IS NOT SPECIFIC REFERENCE TO CONSTRUCTION CONTROLS, THE COLORADO REGULATIONS REFER TO

CONSTRUCTION ACTIVITIES BEING SIGNED OFF ON BY A LICENSED PROFESSIONAL

ENGINEER IN THE STATE AS MEETING THE DESIGN REQUIREMENTS.

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6 CCR 1007-2

Part I

REGULATIONS PERTAINING TO SOLID WASTE DISPOSAL SITES AND

FACILITIES

Applicable CDPHE Regulationscontinued

3.2 DESIGN REQUIREMENTS All portions of the facility design and investigations must be reviewed and sealed by a Colorado professional engineer or reviewed by a professional geologist, as appropriate.

3.2.7 Prior to the acceptance of waste, the owner or operator must submit a report to the Department and the local governing body having jurisdiction documenting that the designed construction has been completed in accordance with the approved plan. The report shall be signed by a Colorado registered professional engineer, approved by the Department and placed in the operating record.

3.3.3 Quality assurance and quality control reports shall be developed and implemented for all engineered structures at the landfill. AEC

3.4 RECORDKEEPING An operating record shall be maintained and include, as a minimum, the following:…..

(D) Construction as-built details

3.5.8 Following closure of each landfill phase, the owner or operator must submit a report to the Department documenting that closure has been completed in accordance with the approved closure plan. The report, which must be signed by a Colorado registered professional engineer, shall be approved by the Department and placed in the operating record.

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Applicable CDPHE Regulationscontinued

APPROVED ENGINEERING DESIGN PLAN INCLUDES:

• LINER SYSTEMS

• LEACHATE COLLECTION SYSTEMS

• FINAL COVER COMPONENTS

• SURFACE WATER CONTROLS

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LINER SYSTEMS AND COMPONENTS

• FOUNDATION AND BARRIER LAYERS USING SOILS

• FLEXIBLE MEMBRANE LINERS

• GEOSYNTHETIC CLAY LINERS

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TYPICAL GCL/SOIL LINER SYSTEM

PROCESSING SOIL FOR LINER SYSTEM

TYPICAL FML LINER SYSTEM

LEACHATE COLLECTION AND RECOVERY SYSTEMS

• Drainage Layers of Aggregate

• Geocomposite Materials

• Sump Designs

• Riser Pipes

• Lateral Drainage Pipes

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FABRICATING SUMP RISER PIPE

PLACING SUMP DRAIN MATERIAL

PLACING CELL FLOOR DRAIN MATERIAL

FINAL COVER COMPONENTS

• Foundation Layers

• Barrier Layers

• Rooting and Frost Layers

• Vegetation Layers

• Flexible Membrane Liners

• Geosynthetic Clay Liners

• Alternate Final CoversAEC

SURFACE WATER CONTROLS

• Channels

• Retention/Detention Ponds

• Drop Structures

• Spillways

• Rip Rap, Armoring, Etc for Erosion Control

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PRECONSTRUCTION DOCUMENTATION

• Drawings, CQA Plan, Technical Specifications, Bid Packages

• Generally done for each construction event at that time (except CQA Plan unless modified)

• Sometimes documents must be submitted for regulatory approval before construction

• Establish survey design coordinates, elevations, and acceptable tolerances before job starts!

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BIDDING

• Lines of authority for all or portions of the project (who contracts and pays who)

• Information necessary so all parties are clear on responsibilities, what is known and not known, procedures and costs for unknowns, schedules and any penalties for exceeding (weather days), anticipated quantities and payment rates if actuals are over or under.

• If earthworks particularly is contracted, it is critical to establish who is responsible for the surveys and lines of authority. Problems can result if this isn’t clear.

• Put all responsibility you can on the contractor to familiarize himself with the job so there are few disputes.

– Pre-bid meeting

– Pre-construction meeting

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PRECONSTRUCTION WORK Why Worry About It??

• Avoid delays and additional costs during construction

• Some components of construction need to be protected soon after placement, i.e., GCL and rain, membranes-fabric-GCL and wind.

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• Know the area to be built and have all design survey data prepared and checked.

• Have all stockpile areas identified.• Have all quantities determined before hand;

earthworks, synthetics, piping.• Have sufficient soil data so no delays occur during

construction, and make sure all soils materials meet specifications. Don’t forget drainage sand/gravel as well.

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PRECONSTRUCTION WORK continued

• Have all material certifications reviewed to ensure they comply with the specifications and requirements.

• Establish a schedule for each component so that personnel, contractors, and materials can be ready to go when needed without delay.

• Know all equipment that will be needed, and have readily available. Compactors, backhoe or excavator for trenches, lifting/unloading equipment for rolled materials.

• Tie-ins with previous construction is critical. Must be able to document continuous liner and leachate collection system. Tie-in is often very difficult.

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PRECONSTRUCTION WORK continued

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POINT NORTHING EASTING ELEVATION DESCRIPTION POINT NORTHING EASTING ELEVATION DESCRIPTION POINT NORTHING EASTING ELEVATION DESCRIPTION

4001 1308266.46 3249214.54 1001 DES PNT4002 1308287.10 3249168.94 1002 DES PNT4003 1308261.81 3249157.13 1003 DES PNT4004 1308308.23 3249123.11 1004 DES PNT4005 1308263.12 3249102.48 1005 DES PNT4006 1308257.08 3249099.72 1003 DES PNT4007 1308329.25 3249078.21 1007 DES PNT4008 1308284.37 3249056.94 1008 DES PNT4009 1308252.20 3249042.29 1009 DES PNT4010 1308350.57 3249033.04 1010 DES PNT4011 1308305.35 3249011.82 1011 DES PNT4012 1308259.97 3248990.72 1012 DES PNT4014 1308371.68 3248987.70 1014 DES PNT4015 1308326.53 3248966.75 1015 DES PNT4016 1308281.45 3248945.41 1016 DES PNT4018 1308393.09 3248942.48 1018 DES PNT4019 1308347.77 3248921.26 1019 DES PNT4020 1308302.47 3248900.22 1020 DES PNT4023 1308414.18 3248897.31 1023 DES PNT4024 1308368.91 3248876.09 1024 DES PNT4025 1308323.68 3248854.94 1025 DES PNT4028 1308435.26 3248851.82 1028 DES PNT4029 1308390.13 3248830.85 1029 DES PNT4030 1308344.79 3248809.54 1030 DES PNT4034 1308456.51 3248806.62 1034 DES PNT4035 1308411.39 3248785.47 1035 DES PNT4036 1308366.03 3248764.06 1036 DES PNT4041 1308477.62 3248761.33 1041 DES PNT4042 1308432.44 3248740.19 1042 DES PNT4043 1308387.25 3248719.01 1043 DES PNT4048 1308498.91 3248716.13 1048 DES PNT4049 1308453.67 3248694.91 1049 DES PNT

4050 1308408.35 3248673.83 1050 DES PNT4056 1308520.07 3248670.93 1056 DES PNT4057 1308474.91 3248649.62 1057 DES PNT4058 1308429.64 3248628.43 1058 DES PNT4064 1308541.44 3248625.43 1064 DES PNT4065 1308496.11 3248604.41 1065 DES PNT4066 1308451.01 3248583.13 1066 DES PNT4073 1308562.67 3248580.19 1073 DES PNT4074 1308517.34 3248559.06 1074 DES PNT4075 1308472.18 3248537.61 1075 DES PNT4082 1308583.79 3248534.70 1082 DES PNT4083 1308538.52 3248513.79 1083 DES PNT4084 1308493.37 3248492.70 1084 DES PNT4092 1308605.03 3248489.73 1092 DES PNT 4093 1308559.77 3248468.46 1093 DES PNT4094 1308514.44 3248447.29 1094 DES PNT4103 1308626.08 3248444.45 1103 DES PNT4104 1308580.81 3248423.27 1104 DES PNT4105 1308535.75 3248401.96 1105 DES PNT4106 1308659.76 3248460.13 1106 DES PNT4107 1308638.85 3248505.69 1107 DES PNT4108 1308617.81 3248550.90 1108 DES PNT4109 1308596.61 3248596.21 1109 DES PNT4110 1308575.27 3248641.46 1110 DES PNT4111 1308554.08 3248686.63 1111 DES PNT4112 1308532.93 3248731.93 1112 DES PNT4113 1308511.67 3248777.28 1113 DES PNT4114 1308490.61 3248822.61 1114 DES PNT4115 1308469.46 3248867.88 1115 DES PNT4116 1308448.32 3248913.07 1116 DES PNT4117 1308427.03 3248958.44 1117 DES PNT4118 1308405.74 3249003.78 1118 DES PNT

4119 1308384.60 3249048.90 1119 DES PNT4120 1308363.41 3249094.39 1120 DES PNT4121 1308342.14 3249139.66 1121 DES PNT4122 1308321.02 3249184.82 1122 DES PNT4123 1308299.89 3249230.05 1123 DES PNT4124 1308278.70 3249275.41 1124 DES PNT4125 1308272.50 3249287.90 1125 DES PNT4130 1308249.78 3249012.86 1130 DES PNT

5575.125576.265576.615577.145577.985578.045578.095578.965579.535579.035580.045580.695580.085580.905581.725581.085582.025582.705581.955582.945583.725583.065584.015584.735584.015584.995585.715585.065585.895586.705586.325586.92

5587.805587.145587.845588.685588.065588.945589.765589.035589.885590.685589.935590.905591.745591.835590.485592.785590.705592.145593.685589.645589.295588.825588.185587.345586.445585.395584.305583.265582.325581.225580.355579.36

5578.415577.425576.505575.555574.615573.795573.335580.28

SURVEY GRID AND POINTS

Construction Quality Assurance (CQA)

Includes procedures and requirements to ensure engineering design plan and specifications are

met in the field.

Necessary for proper construction and to obtain approval from regulators for disposal in a cell

or closure of a cell.

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Oversight and Inspection

• Part time oversight of excavation, generally full time of all else

• Need to observe equipment used, verify proper materials, and procedures, be able to deal with problems as they occur

• Survey and/or review of data. Certified by PLS or PE• Need constant attention to need for survey data. Check off

survey points as certified-don’t do any more work once certified

• Pay attention to allowable tolerances• As-built should generally be demonstrated by survey data, not

by statement of PE or PLS!AEC

Construction Quality Assurance Plan Components

Soil Liner Testing• Required soil types and test parameters established before

construction, i.e., grain size requirements, Atterberg Limits, density and moisture window to result in required permeability.

• Want to get as much “real time” approval as possible during construction to avoid delays or reworking areas.

• If additional soil is needed during construction, can often just do grain size and Atterberg limits to verify same soil type as previously approved. Need to plan ahead and get data before needed.

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Construction Quality Assurance Plan Components

Soil Liner Testing (continued)

• Generally have a permeability specification; demonstrated by a previous laboratory relationship between density and moisture, and resulting permeability. Appropriate density and moisture is verified in field by nuclear methods (real time), and can be verified by sampling and lab testing.

• Followed up by limited number of permeability confirmation samples.

• Liner needs to be placed and compacted in controlled lifts. How to control lift thickness? Because of close tolerances, some contractors find it simpler to very slightly overbuild (1-2”) and shave off to final grades. Needs to be surveyed when graded.

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Construction Quality Assurance Plan Components

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Construction Quality Assurance Plan Components

GCL Testing

• Little actual field testing needed. Verify that the material delivered and used is what was approved by Certification sheets

• May need to do confirmation testing of properties on delivered material.

• Oversight generally limited to inspection for damage, proper placement, overlaps, direction, anchoring, and maintaining protection from moisture.

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Construction Quality Assurance Plan ComponentsFML Testing

• Field testing includes trial welds to ensure equipment is working correctly under field conditions, seam leak testing, and field weld strength testing. Field testing usually has a required frequency (100 percent of seams leak tested, 1 seam strength test every 500 linear feet of seam, etc.)

• Ensure proper overlaps, seaming equipment, alignment of panels, anchoring, inspection for defects and holes, and repair and testing of defective/damaged areas.

• Weather/temperature affects wrinkling/trampolining. Can’t have large wrinkles when covered. Sometimes must cover during cooler weather at night.

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Construction Quality Assurance Components

Assisting Contractors

Questions will arise during construction. CQA personnel should be able to answer/assist appropriately during construction.

Need to be careful of responsibility when directing contractors

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Construction Quality Assurance Components

Documentation

• Necessary to document all aspects of construction to demonstrate proper construction for regulatory approval, assist in correcting problems that are evident later, and critical when building next phase, cell or module.

• SURVEY-SURVEY-SURVEY!!

• Soils – pre-construction lab data, test data and test locations during construction. Make sure required test frequency and results meet requirements. Note failing areas-all failing areas must be corrected, retested and documented.

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Construction Quality Assurance Components

Documentation (continued)

• Synthetics – GCL, PVC, HDPE, Fabric, etc. Have all required certification sheets, have list of all rolls delivered to site and installed (should match certification sheets), record distinct panel numbers, what roll they came off of, where placed and limits, unique seam numbers. Record all testing and document test locations, document location of all repairs. Will need to do as-built that includes panel numbers, seam numbers, test locations and numbers, and repairs

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Construction Quality Assurance Components

Documentation (continued)

• Drainage Materials – sand/gravel or geocomposites. If sand/gravel, must verify at required frequency that meets requirements. If change source, need to re-verify. Pay attention to thickness. If geocomposite used, little field testing necessary, but CQA similar to GCL and FML.

• Piping-must have certification sheets showing piping used meets requirements. Piping may have to be surveyed to verify proper location-end-points should almost always be surveyed for future location.

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Construction Quality Assurance Components

Final Report;

Certified by P.E.-Necessary to Get Regulatory Approval

• Narrative• Survey Data• Laboratory soils and sand/gravel data for materials

used• Soils field test data and locations• Synthetic materials certification sheets• Field test data and locations for synthetic materials• As-built drawings. May have more than one showing

different horizons.