622Geotextiles

622.01DESCRIPTION

This work is furnishing and installing geotextiles.

622.02MATERIALS

Furnish materials in accordance with the following subsections: Permanent Erosion Control Geotextile .................... 716.01 and 716.05 Separation Geotextile .............................................. 716.01 and 716.02 Stabilization Geotextile ............................................ 716.01 and 716.03 Subsurface Drainage Geotextile Filter ..................... 716.01 and 716.04 Temporary Silt Fence Geotextile ............................. 716.06

.1 Classification

A geotextile is defined as any permeable polymeric textile used with foundation, soil, rock, earth, or any other geotechnical engineering related material, as an integral part of a civil engineering project, structure, or system.

aggregate cover material.

conditions.

subgrade conditions.

water into a subsurface drain system while retaining the in-situ soil.

armor systems (riprap) and the in-situ soil to prevent soil erosion and hydraulic uplift pressures.

at a critical resource or R/W line that is adjacent to construction activity. Use silt fence to assist in sediment control by retaining some of the eroded soil particles and slowing the runoff velocity to allow particle settling.

.2 Source Approval

Submit the following information regarding each geotextile proposed for use: • Manufacturer’s name and current address. • Full product name/number. • Geosynthetic material and structure; and • Proposed geotextile use(s). Submit a sample for evaluation. Product acceptance is determined by comparing the average test results of all specimens within a given sample to the Minimum Average Roll Values

. Install geotextiles only after the material has been tested and accepted. Replace all geotextiles installed prior to acceptance that do not meet specifications at Contractor’s expense.

.3 Identification, Shipment and Storage

Conform to ASTM D4873, Standard Guide for Identification, Storage, and Handling of Geotextiles. Clearly label each roll of geotextile shipped to the project with the name and – GEOTEXTILES 2020 EDITION V5.1 address of the manufacturer, full product name/number, quantity, and roll number. For all permanent installations, submit a manufacturer’s certificate of compliance signed by an authorized manufacturer’s official. The certificate must attest that the geotextile meets all the MARV requirements specified in Section 716 as evaluated in accordance with the manufacturer’s quality control program. The Project Manager will reject materials that are mislabeled or misrepresented. Wrap each roll with a material that protects the geotextile, including ends of the roll, from damage due to shipment, water, sunlight, and contaminants. Maintain the protective wrapping during periods of shipment and storage. Do not damage the geotextile or wrapping when unloading or transferring from one location to another. Do not drag the rolls. During storage, elevate geotextile rolls off the ground and adequately cover to protect them from the following: • Site construction damage. • Precipitation. • Ultraviolet radiation including sunlight. • Chemicals that are strong acids or strong bases. • Flames including welding sparks, temperatures in excess of 140 °F (60 °C); and • Mud, dirt, dust, debris, and any other environmental condition that may damage the physical property values of the geotextile.

622.03CONSTRUCTION REQUIREMENTS

.1 General

Prepare the surface on which the geotextile is to be placed so that no damage occurs to the geotextile. Do not drive construction equipment on the geotextile. Dispose of material with defects, rips, holes, flaws, deterioration, or other damage. Do not use defective material in the work. If sewn seams are used for seaming the geotextile, use thread that consists of high strength polypropylene or polyester. Do not use nylon thread. For erosion control applications, use thread that is resistant to ultraviolet radiation. Use thread that is of contrasting color to that of the geotextile itself. For seams that are sewn in the field, provide at least a 10-foot (3 m) length of sewn seam for sampling by the Project Manager before the geotextile is installed. For seams that are sewn in the factory, provide samples as directed and witnessed by the Project Manager at random from any roll of geotextile that is used on the project. For seams that are field sewn, use the same equipment and procedures for both the sampling and production seams. If seams are to be sewn in both the machine and cross- machine direction, provide samples of seams from both directions. Submit the seam assembly description along with the sample of the seam. Include in the description the seam type, stitch type, sewing thread, and stitch density.

.2 Separation/Stabilization Geotextile

Prepare the installation site by clearing, grubbing, and excavating or filling the area to the design grade. This includes removal of topsoil or vegetation. The Project Manager will identify soft spots and unsuitable areas during site preparation. Excavate these areas and backfill with approved granular material and compact as specified. Grade the area to be covered by the 2020 EDITION V5.1 GEOTEXTILES – 622 geotextile to a smooth, uniform condition, free from ruts, potholes, and protruding objects such as rocks or sticks. Spread the geotextile immediately ahead of the covering operation. Do not place geotextile over frozen material. Lay the geotextile smooth without wrinkles or folds on the prepared subgrade in the direction of construction traffic. Remove wrinkles and folds by pulling the geotextile taut as required. Use soil piles or the manufacturer’s recommended method (as approved by the Project Manager) to hold the geotextile in place until the specified cover material is placed. Overlap, sew, or join adjacent geotextile rolls and roll ends as shown in the contract or as directed by the Project Manager. Overlap in the direction shown in the contract. Overlap adjoining edges a minimum of 3 feet (0.9 m) or use sewn seams. On curves, cut or fold the geotextile to conform to the curve. Fold or overlap in the direction of construction and hold in place using pins, staples, or piles of fill or rock. Do not cover the geotextile until inspected for damage by the Project Manager. Repair or replace all damaged geotextile at Contractor’s expense. Make repairs following the manufacturer’s recommendation or use a patch of the same material placed over the damaged area, overlapped at least 3 feet (0.9 m) from the edge of any part of the damage. Sewing repairs are an acceptable alternative. Place fill over the geotextile by dumping onto previously placed material and pushing the material into place. Do not operate any construction equipment directly on the geotextile under any circumstances. Place the fill material in uniform layers so that there is the minimum specified lift thickness between the geotextile and equipment tires or tracks at all times. The minimum thickness of the first lift is 8 inches (200 mm). Do not allow construction equipment to turn on the first lift of material above the geotextile. If the subgrade is very soft with an undrained shear strength less than 500 psf (25 kPa) minimize pile heights to less than 3 feet (0.9 m) and spread piles as soon as possible after dumping to minimize the potential for localized subgrade failure due to overloading of the subgrade. Do not use sheepsfoot or studded compaction equipment on the first lift placed over the geotextile. Stop vibrator on compaction equipment if pumping occurs. Do not operate any construction equipment that results in rutting in excess of 3 inches (75 mm) on the first lift. If rutting exceeds 3 inches (75 mm), decrease the construction equipment size and/or weight or increase the lift thickness. Use only rubber-tired rollers for compaction if any foundation failures occur when placing subsequent lifts. Compact all lifts to the moisture and density requirements for earth embankment specified in Subsection 203.03.3 . Do not blade material down to remove ruts. Fill any ruts or depressions with additional material and compact to the specified density.

.3 Subsurface Drainage Geotextile Filter

Excavate trench in accordance with the contract. Do not allow large voids to occur in the sides and bottom of the trench. Grade the surface to be smooth and free of debris. Place the geotextile loosely with no wrinkles or folds, and with no void space between the geotextile and the ground surface. Press the geotextile into the corners of the trench. Overlap successive sheets of geotextiles a minimum of 1-foot (0.3 m), with the upstream sheet overlapping the downstream sheet. Place a sufficient width of geotextile to entirely cover the perimeter of the trench and allow for the required overlap. In trenches equal to or greater than 1-foot (0.3 m) width, after placing the drainage aggregate, fold the geotextile over the top of the backfill material in a manner to produce a minimum overlap of 1-foot (0.3 m). In trenches less than 1-foot (0.3 m) wide, but greater than 4 inches (100 mm) wide, overlap the geotextile the entire width of the trench. Where the trench is less than 4 inches (100 mm) wide, sew or otherwise bond the geotextile in – GEOTEXTILES 2020 EDITION V5.1 accordance with the manufacturer’s recommendations, as approved by the Project Manager. All seams will be subject to the approval of the Project Manager. If the geotextile is damaged during installation or aggregate placement, place a geotextile patch over the damaged area extending beyond the perimeter of the damaged area a distance of 1-foot (305 mm) or the specified seam overlap, whichever is greater. Place the drainage aggregate immediately following geotextile placement. Cover the geotextile with a minimum of 12 inches (305 mm) of loosely placed aggregate prior to compaction. Compact all placed aggregate to a minimum of 95% of the maximum standard proctor density in accordance with MT 210 .

.4 Permanent Erosion Control Geotextile

Place the geotextile on a smooth graded surface approved by the Project Manager. Place the geotextile loosely and anchor it in place with sand bags, soil piles, or steel pins. Place the geotextile in such a manner that placement of the riprap does not stretch or tear the geotextile. Place the riprap from the bottom of the slope up to the top of the slope. After placement of the riprap, key the geotextile at least 18 inches (455 mm) into the ground at the top of the embankment. Do not key the geotextile in until all of the riprap has been placed on the slope. Secure the geotextile at the toe by lapping the material back and securing with riprap. Limit atmospheric exposure to a maximum of 14 calendar days following lay down to minimize damage potential. Place the geotextile with the machine direction parallel to the direction of water flow, which is normally parallel to the slope (downslope) for erosion control runoff and wave action, and parallel to the stream or channel in the case of stream bank and channel protection. Join adjacent geotextile sheets by either sewing or overlapping. Overlap seams of roll ends a minimum of

1-foot (305 mm) except where placed under water or on slopes 3H:1V or steeper. Overlap seams of roll ends placed under water or on slopes 3H:1V or steeper a minimum of 3 feet (915 mm). Overlap adjacent rolls a minimum of 1-foot (305 mm) in all instances. For slopes flatter than 3H:1V, use pins or staples to hold the overlap in place during placement of riprap. Pin the geotextile loosely so it can easily conform to the ground surface and give when riprap is placed. Do not use pins at overlaps for slopes 3H:1V or steeper. Overlap successive sheets of the geotextile upstream over downstream, and/or upslope over downslope. In cases where wave action or multidirectional flow is anticipated, sew all seams perpendicular to the direction of flow. Avoid damaging the geotextile as a result of the installation process. If the geotextile is damaged during installation, place a patch over the damaged area extending a minimum of 3 feet (915 mm) beyond the perimeter of the damaged area. Begin riprap placement at the toe and proceed up the slope. Avoid stretching and subsequent tearing of the geotextile. Do not drop riprap and heave stone from a height of more than 1-foot (305 mm). Do not allow stones weighing more than 200 lbs (90 kg) to roll down the slope. Do not drop slope protection and smaller sizes of stone material from a height exceeding 3 feet (915 mm), unless the Project Manager approves the procedure following a demonstration showing the geotextiles are not damaged by the procedure. In underwater applications, key the geotextile in at the bottom of the slope. Develop and demonstrate to the Project Manager a method of underwater placement to secure the geotextile in place without damaging the geotextile. Place the geotextile and the backfill material on the 2020 EDITION V5.1 GEOTEXTILES – 622 same day. Backfill all void spaces in the riprap with smaller stone to ensure full coverage of the geotextile. After placement of the riprap, no grading of the slope is allowed if it results in movement of the riprap directly above the geotextile. Replace any geotextile damaged during backfill placement as directed by the Project Manager at the Contractor’s expense.

.5 Silt Fence

Install silt fence in accordance with this specification and with the Detailed Drawings. The maximum cut or fill slope for a silt fence is 2H:1V. For cut or fill slopes steeper than 2H:1V, use alternative methods of soil stabilization BMPs. Use fence posts at least 48 inches (1.2 m) in length. Drive fence posts a minimum of 18 inches (455 mm) into the ground. Use fence posts having a sufficient strength to resist damage during installation and to support the applied loads due to material build up behind the silt fence. There are two types of silt fence installations:

For stabilized silt fence, use woven wire having a maximum of 6-inch (150 mm) mesh spacing and a minimum of 14.5-gauge wire. Excavate a trench at least 6 inches (150 mm) wide by 6 inches (150 mm) deep at the base of the silt fence. The vertical entrenchment component consists of burying the silt fence a minimum of 6 inches (150 mm) below the ground surface. Vertical and horizontal entrenchment of the silt fence consists of placing the silt fence in a “J” configuration in the trench extending a minimum of 6 inches (150 mm) below the ground surface and a minimum of 6 inches (150 mm) horizontally along the bottom of the trench. The initial silt fence installation requires only the vertical entrenchment component unless the Project Manager determines both vertical and horizontal entrenchment components are necessary. If the fence requires replacement due to failure from pullout or undercutting, the subsequent entrenchment must include both vertical and horizontal entrenchment components in a “J” configuration. Backfill the trench with the excavated material and compact. Splice the geotextile with a sewn seam or overlap 2 sections of fence in accordance with the Detailed Drawings . Place the posts at a minimum spacing of 4 feet (1.2 m) and at a maximum spacing of 8 feet (2.4 m). Securely fasten the silt fence geotextile to the upslope side of the fence post. Place silt fence continuously and transverse to the flow. Follow the contours of the site as closely as possible. Place the fence so that water cannot run off and around the end of the fence. Inspect all temporary silt fences immediately after each rainfall and at least daily during prolonged rainfall. Immediately correct any deficiencies at the Contractor’s expense. Make a daily review of the location of silt fences in areas where construction activities have altered the natural contour and drainage runoff to ensure that the silt fences are properly located for effectiveness. Where deficiencies exist as determined by the Project Manager, install additional silt fence as directed by the Project Manager. Repair or replace damaged silt fence promptly. Remove sediment from behind the silt fence when it occurs to one-third the original height. – GEOTEXTILES 2020 EDITION V5.1 Leave the silt fence in place until the Project Manager directs to remove it. Either grade and seed or remove the sediment deposits prior to removal of the fence.

622.04METHOD OF MEASUREMENT

Geotextiles are measured by the square yard (m2) as staked by the Project Manager, except silt fence, which is measured by the yard (m) of fence. Seams, excavated vertical faces, and laps, including any portion of geotextile keyed into the subgrade or fill material, are not measured for payment. For subsurface drainage filter geotextile, the entire drainage trench perimeter, and the top width, is measured for payment.

622.05. BASIS OF PAYMENT

Payment for the completed and accepted quantities is made under the following: Pay Item Pay Unit Geotextile, Erosion Control Square Yard (m2) Geotextile Filter, Subsurface Drainage Square Yard (m2) Geotextile, Separation/Stabilization Square Yard (m2) Geotextile, Silt Fence Yard (m)