10.1 Earthwork

10.1.1 Surface Preparation The Earthwork Contractor will be responsible for preparing the supporting soil according to the project specifications. The CQA Consultant will verify that:

The Installer will certify in writing that the surface on which the geomembrane will be installed within the next 24 hr is acceptable. The certificate of acceptance will be given by the Installer to the Project Manager prior to commencement of geomembrane installation in the area under consideration. The CQA Consultant will be given a copy of this certificate by the Project Manager. The CQA Consultant will also acknowledge approval of the subgrade. After the supporting soil has been accepted by the Installer, it will be the Installer's responsibility to indicate to the Project Manager any change in the supporting soil condition that may require repair work. If the CQA Consultant concurs with the Installer, then the Project Manager will ensure that the supporting soil is repaired.

10.1.2 Anchor Trenches Anchor trenches will be excavated by the Earthwork Contractor (unless otherwise specified) to the lines and dimensions shown on the design drawings, prior to geomembrane placement. The CQA Consultant will verify that anchor trenches have been constructed according to the design drawings. The edge of the trench, over which the geomembrane enters the trench, will be rounded to avoid sharp bends in the geomembrane. There shall be no sharp protrusions on the inside wall of the trench. No loose soil will be allowed to underlie the geomembrane in the trenches. Water shall not be allowed to stand, or soften the soil, in the anchor trench. Responsibility for dewatering of the anchor trench shall be as agreed upon in the contract or at the Preconstruction Meeting. Backfilling of anchor trenches will be conducted in accordance with Section 10.5.

10.2 Geomembrane Placement Before any geomembrane is deployed the documents listed in Appendix B must be received from the Installer and be reviewed and approved by the CQA Consultant and Project Manager.

10.2.1 Field Panel Identification A field panel is a single piece of geomembrane (other than a patch or cap strip) which is seamed in the field: i.e. a roll or a portion of roll cut in the field. It will be the responsibility of the CQA Site Superintendent to ensure that each field panel is given an "identification code" (number or letter-number) consistent with the layout plan. This identification code will be agreed upon by the Project Manager, Installer, and CQA Consultant. This field panel identification code should be as simple and logical as possible. It will be the responsibility of the Installer to ensure that each field panel placed is also marked with the original roll number. The identification code and roll number will be marked at a location agreed upon by the Project Manager, Installer, and CQA Consultant. Typically, panels will be numbered in the order in which they are placed. The CQA Site Superintendent will establish a table or chart showing correspondence between roll numbers and field panel identification codes. The field panel identification code will be used for all CQA records.

10.2.2 Field Panel Placement No geosynthetics shall be deployed, joined, or tested unless a representative of the CQA Consultant is present to monitor such activities.

10.2.2.1 Location The CQA Consultant will verify that field panels and seam orientations are approximately as indicated in the Engineer's or Installer's approved layout plan, or as modified.

10.2.2.2 Compensation for Material Expansion and Contraction

Unless provided by the designer, as it should be, the Installer will be responsible for determining the required amount of compensation that must be installed in the geomembrane to ensure that it will not be unduly tensioned due to temperature variations in service. Such calculations shall be shown to the CQA Consultant and Project Manager. The Installer will be responsible for ensuring that sufficient HDPE geomembrane is installed to compensate for contraction of the material during anticipated lower temperatures and to prevent expansion and excessive wrinkling at possible higher covering temperatures.

The methods of installing compensation will be discussed with, and approved by, the Project Manager and the CQA Consultant. The geomembrane must not be tensioned and must be fully supported by the subgrade when it is covered by soil or liquid ballast.

10.2.2.2 Intimate Subgrade Contact

Only that amount of geomembrane will be deployed in one day that can be covered by other required geosynthetics and the required thickness of cover soil. The cover soil will initially be placed as ballast around the periphery of that section of geomembrane. The CQA Consultant will monitor the placement of geomembrane and soil to confirm that the geomembrane is essentially in complete contact with the subgrade at the end of the working day, and is restrained in this position, without excessive tension, by the peripheral soil. The CQA Consultant will monitor the spreading of cover soil at the start of the first shift of the next day to confirm that no standing or folded wrinkles in the geomembrane are covered by soil. The geomembrane must be in intimate contact with the subgrade. At all times the exposed edges of geosynthetics will be kept clean and protected from damage.

10.2.2.3 Installation Schedule Field panels will be placed one at a time, and each field panel will be seamed immediately after its placement (in order to minimize the number of unseamed field panels exposed to wind). It is beneficial to "shingle" overlaps in the downslope direction to facilitate drainage in the event of precipitation, shingling should also be done in the downstream direction to minimize resistance to flow. It is also beneficial to proceed downslope and in the direction of (with) prevailing winds. Scheduling decisions must be made during installation, in accordance with varying environmental conditions. In any event, the Installer will be fully responsible for the decisions made regarding placement procedures. The CQA Consultant will evaluate every change in the schedule proposed by the Installer and advise the Project Manager on the acceptability of that change. The CQA Consultant will verify that the condition of the supporting soil is still satisfactory for installation of geomembrane. The CQA Consultant will record the identification code, roll number, location, weather conditions, and date of installation of each field panel.

10.2.2.4 Weather Conditions Geomembrane placement will not proceed at geomembrane temperatures below -20°C unless approved by the project engineer. Geomembrane seaming will not proceed at geomembrane temperatures between 0°C and -20°C or above 75°C unless approved by the Project Manager. Approval will not be unreasonably withheld provided the Installer can demonstrate the ability to produce satisfactory seams. The frequency of trial seams, or seam destructive test sampling, (Section 10.3.6) may be increased at extreme geomembrane temperatures (<5°C, >75°C). Geomembrane placement will not be done during any precipitation, in an area of ponded water, or during excessive winds except as approved in an Action Decision Meeting. NOTE: The only temperature of significance is the actual geomembrane temperature, not the ambient temperature. When exposed to sunlight the geomembrane temperature will be significantly higher than ambient.

The CQA Consultant will verify that the above conditions are observed. Additionally, the CQA Consultant will verify that the supporting soil has not been damaged by weather conditions. The CQA Site Superintendent will inform the Project Manager if the above requirements are not observed.

10.2.2.5 Geomembrane Placement The CQA Consultant will verify that:

• equipment used does not damage the geomembrane as a result of handling, trafficking, excessive heat, leakage of hydrocarbons, or by other means;
• any All-Terrain Vehicles (ATVs) used to deploy geosynthetics exert ground pressures less than 55 kPa (8 psi).
• To be practical it should be noted that a 200lb man walking on the liner will exert a bed of pressure on the liner of about 100 psi (690Pa)!
• ATVs are not operated: 1) at excessive speeds, 2) in tight turning circles, 3) under extreme breaking and accelerating conditions, 4) with dirty tires, and 5) over wrinkles, that might damage the geomembrane.
• the prepared surface underlying the geomembrane has not deteriorated since previous acceptance, and is still acceptable immediately prior to geomembrane placement;
• any geosynthetic elements immediately underlying the geomembrane are clean and free of debris;
• personnel working on the geomembrane do not smoke, do not wear hard-soled shoes, and do not engage in activities which could damage the geomembrane;
• frequently used pathways up and down geomembrane on slopes are protected by a well-secured roll of geotextile;
• the methods used to unroll the panels do not cause excessive scratches or crimps in the geomembrane and do not damage the supporting soil;
• the method used to place the panels minimizes wrinkles (especially differential wrinkles between adjacent panels);
• geomembrane is not allowed to unroll freely down a slope;
• geomembrane is not placed under tension, unless approved by the Project Manager;
• adequate temporary loading and/or anchoring (e.g., sand bags, tires), that does not damage the geomembrane, has been placed to prevent uplift by wind;
• direct contact of equipment with the geomembrane shall not be allowed, except as previously described for ATVs used to deploy geosynthetics. The geomembrane shall be protected by geotextiles, extra geomembrane, soil layers, or suitable materials, in areas where equipment may be used or traffic may be expected;
• only hook bladed utility knives are used to cut through the geomembrane;
• appropriate care is to be taken to prevent shock and explosions caused by static electricity discharges;
• all handholds cut for moving panels and damage caused by clamps are repaired; and
• panels are not moved such that subgrade soil can peel the underside seam flap.

The CQA Site Superintendent will inform the Project Manager if the above requirements are not observed.

10.2.2.6 Temporary Ballasting Temporary ballasting around the edges of the installed liner shall be done with sandbags or equivalent non-damaging ballast material (e.g. tires without reinforcing wires exposed). Sandbags shall be handleable by one person and shall be spaced to provide adequate uplift protection against typical winds that might reasonably be expected to occur prior to the addition of adjacent panels or prior to permanent ballasting.

10.2.2.7 Damage The CQA Consultant will visually examine each panel, after placement and prior to seaming, for damage. The CQA Site Superintendent will advise the Project Manager which panels, or portions of panels, should be rejected or repaired. Damaged panels or portions of damaged panels, which have been rejected will be marked, and their removal from the work area recorded by the CQA Consultant. Repairs will be made according to procedures described in Section 10.4. At a minimum, the CQA Consultant will ensure that:

• each panel is placed in such a manner that it has not been, or is unlikely to be, damaged; and
• any tears, punctures, holes, thin spots, and damaging inclusions, gouges, and protuberances etc., are marked for repair, or the panel is rejected.

10.3 Field Seaming

10.3.1 Seam Layout Prior to the commencement of installation activities the Installer will provide the Project Manager and the CQA Consultant with a proposed panel layout drawing. The CQA Consultant will review the panel layout drawing and verify that it is consistent with the accepted state-of-practice and this CQA Plan. No panels may be seamed in the field without the Project Manager's approval. In addition, panels that significantly change the layout drawing, (e.g. that change the orientation of seams) shall not be installed without the Project Manager's prior approval. It is, however, recognized that such a drawing is only a guide and will, in practice, require modification. In general, seams should be oriented parallel to the line of maximum slope, i.e., oriented up and down, not across, the slope. In corners and other geometrically complex locations, the number of seams should be minimized. No base seam or tee seam will be less than 2 m from the toe of slopes, or areas of potential stress concentrations, unless otherwise authorized by the Project Manager.
If roll end seams are unavoidable on slopes, the upslope panel shall overlap the downslope panel and adjacent panel cross-seams shall be staggered by at least 2 m. A seam numbering system compatible with the panel numbering system will be agreed upon at the Resolution or Preconstruction Meeting. Seams are usually identified by the panel numbers on each side, e.g. seam 1 / 2, for the seam between panels 1 and 2.

10.3.2 Seaming Equipment and Products Approved methods for field seaming are thermal fusion (hot wedge, hot air, or combination) seaming and extrusion seaming. Proposed alternate methods will be documented and submitted to the Project Manager and CQA Consultant for approval. Only apparatus that has been specifically approved by make and model will be used. The Installer will use appropriate measuring equipment to ensure that required temperatures are being achieved.

The Project Manager will submit all documentation to the CQA Consultant for his concurrence.

10.3.2.1 Fusion Seaming Fusion seaming must be done with automated self-propelled machines. The fusion seaming machines will be equipped with gauges giving hot wedge temperatures geomembrane temperature, wedge. Temperature, speed, and nip roll pressure settings will be verified by the Installer prior to each seaming period. Nip roll and wedge geometries shall be such as to minimize residual stresses at the edge of the seam, i.e. to minimize reduction in stress cracking resistance of the geomembrane. The CQA Consultant will log ambient conditions, geomembrane temperatures, seaming apparatus temperatures and speeds, equipment serial number, and operator initials. The CQA Consultant will also verify that:

• the Installer maintains on-site the number of operable seaming machines decided at the Resolution Meeting;
• equipment used for seaming does not damage the geomembrane;
• for tee seam intersections, all edge flaps are cut back to the edge of the outermost peel-tested track of the seam prior to seaming;
• electric generators and fuel containers are placed on a smooth protective layer such that no damage occurs to the geomembrane;
• a smooth insulating plate or fabric is placed beneath the hot seaming apparatus after usage;
• the geomembrane is protected from damage in heavily-trafficked areas; and
• build-up of moisture between the sheets is prevented. To accomplish this a movable protective layer may be used directly below each overlap of geomembrane that is to be seamed.

  10.3.2.2 Extrusion Seaming Extrusion-seaming apparatus will be equipped with gauges giving the relevant temperatures of the apparatus such as the temperatures of the extrudate, nozzle, and preheat air. The Installer will provide documentation (including QC certificates) regarding the welding rod or resin pellets to the Project Manager and the CQA Consultant, that show that the resin is the same HDPE resin as the geomembrane itself order a Melt Index that is compatable with the geomembrane. Other welding rod resins must be approved by the Project Manager and the CQA Consultant. The CQA Consultant will log apparatus temperatures, extrudate temperatures, ambient conditions, and geomembrane temperatures at appropriate intervals. The CQA Consultant will verify that:

• the Installer maintains on-site the number of operable seaming machines decided at the Resolution Meeting;
• equipment used for seaming will not damage the geomembrane;
• the extruder is purged prior to seaming until all heat-degraded extrudate has been removed from the barrel;
• feed resin is maintained clean and dry;
• the electric generator and fuel containers are placed on a smooth intermediate layer such that no damage occurs to the geomembrane;
• a smooth insulating plate or fabric is placed beneath the hot seaming apparatus after usage; and
• the geomembrane is protected from damage in heavily trafficked areas.

10.3.3 Seam Preparation The CQA Consultant will verify that:

10.3.4 Weather Conditions for Seaming The following protocols will be observed during seaming:

If the Installer wishes to use methods which may allow seaming at geomembrane temperatures below 0°C or above 75°C, the Installer will demonstrate (by testing trial seams) that such methods produce seams which are entirely equivalent to seams produced at geomembrane temperatures above 0°C and below 75°C, and that the overall quality of the seam and durability of the geomembrane are not adversely affected. In addition, the Installer will prepare written certification that states that the seaming procedure does not cause any physical or mechanical modification to the geomembrane that will generate any short or long-term damage to the geomembrane liner. The CQA Consultant will verify that these requirements are observed and will advise the Project Manager if potential problems are perceived. The Project Manager will then decide if the seaming will be stopped or postponed. Such decisions may be the subject of an Action Decision Meeting.

10.3.5 Overlapping and Temporary Bonding The CQA Consultant will verify that:

• the panels of geomembrane have an overlap sufficient to allow peel tests to be performed on each weld track i.e. free flaps more than 10 mm wide.

The CQA Consultant will log all relevant temperatures and conditions, and will log and report any non-compliance to the Project Manager. If protective layers of geomembrane are placed on the barrier layer geomembrane for any purpose (e.g. puncture protection in drainage trenches), they shall not be tack or spot welded to the barrier layer. They shall be fully welded, except for a small pressure relief segment, along the complete periphery of the protective layer or they shall not be welded at all.

10.3.6 Trial Seams Trial seams will be made by each machine/operator combination on strips of HDPE geomembrane to verify that seaming can be successfully performed. Such trial seams will be made at the beginning of each seaming period (i.e., at the beginning and middle of each working shift), but at least once every four hours, for each seaming apparatus/operator combination used in the seaming period. In addition, a new trial seam will be conducted when a welding apparatus has been restarted after being switched off. A trial seam will also be made in the event that the geomembrane temperature changes more than 25°C since the last passing trial seam. Trial seams will be made under the same conditions as production seams will be made e.q. or soil, GCL, on slopes, or walls, as appropiate. When geomembrane temperatures are below 5°C or higher than 75°C more frequent trial seams may be required. In general, trial seams will be conducted as follows: The trial seam sample will be at least 1.5 m long by 0.3 m wide with the seam centered lengthwise. Seam overlap will be as indicated in Section 10.3.5. The CQA Consultant will observe all trial seam procedures. Four specimens, each 25 mm wide and a minimum of 150 mm long, will be cut from the center section of the trial seam sample by the Installer. Two specimens will be tested in shear and two in peel using a calibrated field tensiometer. They should meet project specifications. If any specimen fails, the entire operation will be repeated. If the second trial seam fails, the seaming apparatus and seamer will not be approved for production seaming until the deficiencies are corrected and two consecutive successful trial seams are achieved. The remainder of the successful trial seam sample will be assigned a number and marked accordingly by the CQA Consultant, who will also log the date, time, geomembrane temperature, number of seaming unit, settings, name of seamer, and pass or fail description. The remainder of the sample will be cut into two pieces, one each to be retained by the Owner, and Installer. A trial seam shall also be prepared by each seaming machine/operator at the completion of seaming each day to determine whether changes in seam quality might have occurred during the last part of the seaming period.

Alternatively, a seam destructive sample could be required at the end of the day.

10.3.7 General Seaming Procedure Unless otherwise specified, the general seaming procedure used by the Installer will be as follows:

Each seam will be labelled with the seaming machine number, the operator's initials, machine temperature and speed settings, date, time, and direction seamed. The CQA Consultant will monitor the above seaming procedures, and will inform the Project Manager of any unsatisfactory deviations from standard practice.

10.3.8 Nondestructive Seam Continuity Testing

10.3.8.1 Concept The Installer will nondestructively test all field seams over their full length using a vacuum test unit, air pressure test (for double fusion seams only), spark test, or other approved method. Vacuum testing, air pressure testing, and spark testing are described in Sections 10.3.8.3, 10.3.8.4, and 10.3.8.5 respectively). The purpose of nondestructive testing is to check the continuity of seams. It does not provide any information on seam strength. Continuity testing will be carried out as the seaming work progresses, not at the completion of all field seaming. Nondestructive testing will not be permitted unless there is, in the opinion of the CQA Consultant, adequate illumination. The CQA Consultant will:

• observe all nondestructive testing;
• record location, date, test unit number, operator, and outcome of all testing; and
• log and inform the Installer and Project Manager of any required repairs.

The Installer will complete any required repairs in accordance with Section 10.4. The CQA Consultant will:

• observe the repair and re-testing of the repair;
• mark on the geomembrane that the repair has been successfully made and tested; and
• document the results.

The following procedures will apply to segments of seams that cannot be nondestructively tested:

• All such seam segments will be cap-stripped with the same type of geomembrane material, or
• All such seam segments will be very carefully prepared and welded by the master seamer under the observation of the consultant.
• If the seam is accessible to testing equipment prior to final installation (e.g. after prefabrication), the seam will be nondestructively tested prior to final installation.

The installer will write the details of each seam nondestructive test on the geomembrane. For air pressure tests this will include the initials of the tester, the date, start time and pressure, end time and pressure, and pass or fail result. For vacuum testing this will include the initials of the tester, the date, and pass or fail result. For spark testing this will include the initials of the tester, the date, voltage setting, and pass or fail result. When a test fails, the number of the appropriate repair will also be recorded on the geomembrane.

10.3.8.2 Submittals Prior to any nondestructive testing, the Installer shall submit to the Owner and CQA Consultant calibration certificates for all pressure gages to be used during vacuum and air pressure testing, or shall otherwise demonstrate that all gages are in satisfactory working condition.

10.3.8.3 Vacuum Box Testing (ASTM D5641) The equipment will be comprised of the following:

• a vacuum box assembly consisting of a rigid housing, a transparent viewing window, a soft neoprene gasket attached to the bottom, port hole, valve assembly, and a vacuum gauge;
• a vacuum tank and pump assembly equipped with a pressure controller and pipe connections;
• a pressure/vacuum hose with fittings and connections;
• a soapy solution that does not cause environmental stress cracking in the geomembrane, and
• a soap solution applicator.

The following procedure will be followed:

• for fusion seams (not normally tested with a vacuum box), cut off the free flap with an approved cutter (so that the lower geomembrane is not damaged) prior to testing the seam;
• energize the vacuum pump and reduce the tank pressure to approximately 5 kPa gauge;
• with a soapy solution, wet a strip of geomembrane which is wider and longer than the vacuum box;
• place the box over the wetted area;
• close the pressure relief valve and open the vacuum valve;
• ensure that a leak-tight seal is created;
• examine the geomembrane seam through the viewing window for the presence of soap bubbles (large bubbles, or fine froth) for a period of not less than 5 seconds;
• if no bubbles or foam appear after 5 seconds, close the vacuum valve and open the pressure relief valve. Move the box over to the adjoining section of seam, with some overlap, and repeat the process;
• all areas where soap bubbles appear will be marked and repaired in accordance with Section 10.4.3; and
• excess soap solution shall be cleaned or rinsed off the geomembrane and seam.

  10.3.8.4 Air Pressure Testing (ASTM D5820) The following procedures are applicable to those seaming processes which produce a double track seam with a central channel. The equipment will be comprised of the following:

The following procedures will be followed:

• seal both ends of the seam to be tested;
• insert the pressure-feed device into the channel of the seam;
• energize the air pump to a pressure between 165 and 275 kPa (depending on geomembrane thickness) as indicated in Table 2, close the valve, and allow the temperature of the air in the channel, and thus the pressure, to stabilize for about 2 minutes;

10.3.8.5 Spark Testing (ASTM D6365) There are two types of spark testing equipment - AC and DC. The ASTM D6365 standard is written for DC equipment, which often uses a metal brush for the search electrode. The AC equipment is typically a hand held unit with a rounded tip probe. Spark Testing is frequently used on short, detail (sump, penetration) extrusion welds that cannot be tested by vacuum box testing, it is used on cost-in liner welds. Occasionally it is used on long extrusion seams as the primary nondestructive test method. The same general test method can also be applied to the geomembrane panels themselves when they are manufactured with an electrically conductive bottom surface layer. For seams, a copper wire or tape is placed within the geomembrane overlap, just to the inside of the center of the extruded bead. The wire is exposed at one end of the seam or it is buried in the conductive subgrade.

  The test procedure is as follows:

• DC equipment connect the negative (ground) electrode of the testing equipment to the exposed end of the copper wire, or to a grounding rod if the copper wire is buried in the subgrade.
• Calibrate using a seam with a known leak path of the largest reached distance
• Connect the positive electrode to the wire brush or other type of search electrode.
• Clean all debris and moisture from the seam area.
• Apply a potential difference of between 20 and 55 kVDC, as determined in the calibration test, between the electrodes. Table 4 D6365 recommends the DC voltage to be used for different lengths of leak passages based on the following equation:

V =kd 0.5
Where V= Applied Voltage (s)
K= Constant, 7900
D= Distance to test (mm)

Table 4.
Typical example of required voltage settings :

The distance to test is typically not the thickness of the geomembrane but the distance from the edge of the extrusion bead to the copper wire.

• Sweep the search electrode over the surface of the seam, maintaining contact with the extruded bead and the top of the lower geomembrane at the edge of the bead.
• Monitor for audible and/or visible spark discharges that are indicative of a defect. Mark defects for repair.

Care must be taken when spark testing almost completed landfill caps - a spark can cause a small landfill gas explosion.

Spark testing must not be performed when the liner is wet. It should be recognized that this test requires no signal be generated for a passing result. There are many conditions in addition to adequate seaming under which no signal will be generated: proper connections may not be made, the voltage may be set too low, the search electrode may be held too far away. Periodic calibration should be performed.

10.3.8.6 Visual Examination Air pressure, vacuum box, and spark testing methods apply only to seams. Installer and CQA personnel shall continuously visually examine the geomembrane panels for the presence of other penetrating and nonpenetrating defects and shall continuously feel for protuberances when walking on the geomembrane. Visual examination should take advantage of low angles of sunlight and early morning condensation on the geomembrane. As a final shape of CQA the Project Engineer reserves the right to require an electrical, or other type of nondestructive liner integrity (leak location) survey to be performed on the complete lining system. A separate specification document is needed for such surveys.

10.3.9 Destructive Testing

10.3.9.1 Concept Destructive seam tests will be performed at selected locations. The purpose of these tests is to evaluate seam bond strength and the effects of seaming on the adjacent geomembrane. Seam strength testing will be done as the seaming work progresses, not at the completion of seaming.

10.3.9.2 Location and Frequency The CQA Site Superintendent will select locations where seam samples will be cut out for laboratory testing. Those locations will be established as follows:

• A minimum frequency of one sample for every 150 m of seam made by each extrusion machine/operator combination and each fusion machine each day - unless a different frequency is stated in the project specifications.
• Conditions under which testing frequency may be increased or decreased as the project progresses will be agreed upon by the Installer, Project Manager, and CQA Manager at the Resolution or Preconstruction Meeting. Such conditions may be as described in the Method of Attributes, GRS.GM 14.
• Test locations will be determined during seaming at the CQA Site Superintendent's discretion. Selection of such locations may be prompted by suspicion of overheating, contamination, offset seams, or any other evidence of imperfect seaming.
• If trial seams are not made at the end of the day one sample for destructive testing shall be removed from the last seam made by each seaming machine at the end of each working day.

The Installer will not be informed in advance of the locations where the seam samples will be taken. Test frequencies may be increased or decreased at the CQA Site Superintendent's discretion depending on the consistency of the test results.

10.3.9.3 Sampling Procedure Samples will be cut by the Installer as the seaming progresses in order to have laboratory test results before the geomembrane is covered by another material. The CQA Consultant will:

• observe sample cutting;
• assign a number to each sample, and mark it accordingly; and
• record the sample location on the layout drawing.

All holes in the geomembrane resulting from destructive sample removal will be immediately repaired in accordance with repair procedures described in Section 10.4.3. The continuity of the new seams in the repaired area will be tested according to Section 10.3.8.

10.3.9.4 Size of Samples At a given sampling location, two types of samples will be taken by the Installer. First, two pairs of specimens for field peel and shear testing will be taken. Each of these specimens will be 25 mm wide by at least 150 mm long, with the seam centered across the width. The distance between these two pairs of specimens will be 1.1 m. If both pairs of specimens pass the field tests described in Section 10.3.9.5, a sample for laboratory testing will be taken. The sample for laboratory testing will be located between the two pairs of specimens taken for field testing. Unless determined otherwise at the Preconstruction Meeting, or in the Project Specifications, the destructive sample will be 0.3 m wide by 1.1 m long with the seam centered lengthwise. The sample will be cut into three parts and distributed as follows:

• one portion, measuring 0.3 m x 0.3 m, to the Installer for QC laboratory testing;
• one portion, measuring 0.3 m x 0.3 m, to the Owner for archive storage; and
• one portion, measuring 0.3 m x 0.5 m, to the CQA Consultant for CQA Laboratory testing.

  10.3.9.5 Field Testing The four 25 mm wide specimens mentioned in Section 10.3.9.4 will be tested in the field, by calibrated gaged tensiometer, one of each pair in peel and one in shear. If any field test specimen fails to pass the criteria of Table 4 and the project specifications, then the procedures outlined in Section 10.3.9.9 will be followed. The CQA Consultant will witness all field tests and mark all samples and portions with their unique sample number. The CQA Consultant will also log the date and time of sampling, and test pass or fail description. If the two pairs of specimens meet the project specifications, the sample qualifies for testing in the laboratory; if they fail, the seam should be repaired in accordance with section 10.4.3.

10.3.9.6 Construction Quality Assurance Laboratory Testing Destructive test samples will be packaged and shipped to the CQA laboratory by the CQA Consultant, in a manner which will not damage the test sample. The Project Manager will verify that packaging and shipping conditions are acceptable. The Project Manager will be responsible for storing the archive samples. This procedure will be fully outlined at the Resolution Meeting. Test samples will be tested by the CQA Laboratory. Testing will follow ASTM D6392, but with no requirement for sample conditioning time. The minimum acceptable values to be obtained in these tests are those indicated in the specifications or as shown in Table 5. Five specimens will be tested in peel and five in shear. Specimens will be selected alternately by test from the samples (e.g., peel, shear, peel, shear, etc.). The CQA Laboratory will provide test results no more than 6 hours after they receive the samples. The CQA Site Superintendent will review laboratory test results as soon as they become available, and make appropriate recommendations to the Project Manager.

10.3.9.7 Installer's Laboratory Testing The Installer's laboratory test results will be available to the Project Manager and the CQA Consultant for review.

10.3.9.8 Destructive Sample Pass/Fail Criteria The criteria shown in Table 5, or the requirements of the project specifications (whichever are the more comprehensive) must be met for the acceptance of peel and shear test specimens: TABLE 4 IN CQA PLAN

TABLE 5. SEAM SPECIMEN TEST (ASTM D4437) SPECIFICATIONS

The peel criteria apply to both tracks of double track seams. Nine out of the ten specimens in a seam destructive sample must meet the criteria above for acceptance of the complete destructive sample.

The CQA Consultant will ensure that the CQA Laboratory retains all sample and specimen remnants, clearly labelled, for at least 30 days after the last specimen for the project has been tested.

10.3.9.9 Procedures if Destructive Sample Fails The following procedures will apply whenever a sample fails a destructive test, whether that test is conducted by the CQA Laboratory, the Installer's laboratory, or on the field tensiometer. The Installer has two options:

• Reconstruct the seam between the nearest passing destructive test locations on each side of the failed sample; or
• Trace the seaming path to an intermediate location (3 m minimum from the failed test location in each direction) and take a small sample for an additional field test at each location. If these additional samples pass tensiometer testing, then full destructive test samples should be taken. If these laboratory destructive test samples pass the tests, then the seam should be reconstructed between these locations by capping. If either sample fails, then the process is repeated to establish the zone in which the seam should be reconstructed.

If a fusion-type seam fails destructive testing and the Installer chooses to repair the seam, the only acceptable repair method is as described in Section 10.4.3.
Only seams bounded by two locations from which samples passing laboratory destructive tests have been taken will be considered acceptable. An additional destructive test sample will be taken from repair seams when the length of a reconstructed seam exceeds 50 m. This sample must pass destructive testing or the procedure outlined in this section must be repeated. The CQA Consultant will document all actions taken in conjunction with destructive test failures.

10.4 Defects and Repairs

10.4.1 Identification All seams and non-seam areas of the geomembrane will be examined by the Installer and the CQA Consultant for identification of defects, protruding and penetrating objects, lack of subgrade support, overheating, overgrinding, holes, blisters, undispersed raw materials, scratches and gouges, and any sign of contamination by foreign matter. To facilitate the examination the geomembrane surface will be kept clean by the Installer (or as agreed at the Preconstruction Meeting).

10.4.2 Evaluation Each suspect location, both in seam and non-seam areas, will be nondestructively tested using an appropriate method, such as vacuum box testing. Additional methods, such as electrical methods and infrared thermography, may also be used. Each location which fails the nondestructive testing will be marked by the CQA Consultant and repaired by the Installer. Work will not proceed with any materials which will cover locations that have been repaired until passing destructive and nondestructive test results have been obtained on the repairs.

10.4.3 Repair Procedures Any portion of the geomembrane exhibiting a flaw, or failing a destructive or nondestructive test, will be repaired. Several procedures exist for the repair of these areas. The final decision as to the appropriate repair procedure will be agreed upon between the Project Manager, Installer, and CQA Manager at the Preconstruction Meeting or at an Action Decision Meeting. The procedures available include:

• patching, used to repair all penetrating holes, tears, undispersed raw materials, and contamination by foreign matter;

• spot beading, used to repair small surface scratches, or other minor, localized nonpenetrating flaws; and
• capping with a strip of geomembrane, used to repair long lengths of failed seams.

In addition, the following provisions will be satisfied:

• surfaces of the geomembrane which are to be repaired will be abraded no more than 30 minutes prior to the repair;
• all surfaces must be clean, free of all particulate matter, and dry at the time of the repair;
• all seaming equipment used in repairing procedures must be approved;
• the repair procedures, materials, and techniques will be approved in advance of the specific repair by the Project Manager and CQA Consultant;
• patches and caps will extend at least 150 mm beyond the edge of the defect, and all corners of patches will be rounded with a radius exceeding 75 mm;

10.4.4 Verification of Repairs Each repair will be numbered and logged. Each repair will be nondestructively tested using one of the methods described in Section 10.3.8 or another approved method. Repairs which pass the nondestructive test will be considered acceptable. Large caps may be of sufficient extent to require destructive testing, at the discretion of the CQA Consultant. Failed tests will require the repair to be redone and retested until a passing test results. The CQA Consultant should observe all nondestructive testing of repairs and will record the date of the repair and test result.

10.4.5 Large Wrinkles When seaming of the geomembrane is completed (or when seaming of a large area of the geomembrane is completed) and prior to placing overlying materials, the CQA Consultant will observe the sizes and distribution of geomembrane wrinkles. The CQA Consultant will discuss with the Project Manager which wrinkles should be cut and reseamed by the Installer. The seam thus produced will be tested like any other seam.

10.4.6 Bridging of Geomembrane Bridging or trampolining of the geomembrane at any temperature higher than the design minimum service temperature or higher than the expected covering temperature at any location at any time shall be considered unacceptable. Compensating material will be installed at these locations. The geomembrane must be fully supported by the subgrade at the time of covering with soil or liquid. The minimum service temperature includes any period (after acceptance of the installation by the owner) when the liner is uncovered even though final service may involve covering the liner.

10.4.7 Geomembrane Anchoring The CQA Consultant will ensure that the periphery of the geomembrane is anchored in an anchor trench, welded to an HDPE strip cast into concrete, fastened by a batten strip, or otherwise clamped, according to the design, such that access of liquid (contained liquids, rainwater) to the underside of the geomembrane is prevented. The CQA Consultant will ensure that all gasketting and other components of a
mechanical battening system are present according to the design. The CQA Consultant will ensure that all butt and corner joints in cast in strips have been welded to provide water tight seals. The geomembrane will not be placed on loose soil in the anchor trench. The geomembrane must be permanently anchored in the anchor trench, as soon as possible after installation, particularly in windy and/or wet environments. However, it is advisable to allow the geomembrane to go through one cold cycle (overnight) to evaluate the potential for contraction and trampolining before backfilling the trench. The geomembrane must lie flat against the anchor trench front wall and floor. It must not be folded.

10.5 Backfilling of Anchor Trench Anchor trenches will be adequately drained to prevent ponding or softening of the soils while the trench is open. Anchor trenches will be backfilled and compacted by the Earthwork Contractor or the Installer as outlined in the specifications or drawings. Care will be taken when backfilling the trenches to prevent any damage to the geosynthetics. Sharp rocks and stones shall be removed from soils before filling in the anchor trench. There shall be no holes in the geomembrane placed in the anchor trench. The CQA Consultant will observe the backfilling operation and advise the Project Manager of any problems.