6-197 SECTIO N 649 – GEOTEXTIL E FABRIC 649.0 1 DESCRIPTION . This work shall consist of furnishing and placing geotextiles in underdrain trenches, under embankment s, for embankment reinforcement, under riprap and stone fill, behind retaining structures, over roadbed subgrade s, between railbed and roadbed subgrade s, and beneath pavement overlays. 649.0 2 MATERIALS . Materials shall meet the requirements of the following subsection s: Geotextile for Roadbed Separator ................................ ................................ .............. 720.02 Geotextile Under Railroad Ballast ................................ ................................ ............. 720.03 Geotextile Under Stone Fill ................................ ................................ ....................... 720.04 Geotextile for Underdrain Trench Lining ................................ ................................ ..720.05 Geotextiles shall conform to the following:
a.Where sewn seams are used, the Contractor shall furnish the manufacturer’s wide strip tensile test results as part of the certification . The results must verify that the seam meets or exceeds the specified average minimum roll values for the grab tensile strength of the geotextiles, or wide strip tensile strength for reinforcement applications.
b.Field seams, where used, shall be in accordance with the manufacturer’s recommendations. 649.0 3 GENERAL REQUIREMENTS . The rolls of geotextile shall be protected against damage and deterioration until incorporated into the project . The geotextile shall be dry at the time of installation. The geotextile will be rejected if, at the time of installation, it has defects, det erioration, or damage as determined by the Engineer. 649.0 4 INSTALLATION .
a.General Requirements . The surface receiving the geotextile shall be prepared to a smooth condition, free of obstructions, depressions, and debris, unless otherwise directed by the Engineer . The geotextile shall not be dragged on the ground or mishandled in any way. The geotextile shall be placed loosely and without wrinkles so that placement of the overlying material will not tear the geotextile. The geotextile shall be lapped as specified at the ends and sides of adjoining sheets. In addition to the above general requirements, the following specific requirements shall be followed for the specified application: 6-198 (1) Geotextile Placement on Slopes . The geotextile sheets shall be placed with the machine direction oriented perpendicular to the slope . When the geotextile is placed on slope s steeper than 1:6 (V:H) , the upper sheets shall lap over the top of the lower sheets. The laps shall be se curely anchored to the ground surface with pins or stakes as necessary to prevent slippage and tearing of the geotextile. As specified by the geotextile manufacturer or as directed by the Engineer, placement of fill material on the geotextile shall start a t the toe of the slope and proceed upward.
2.Geotextile Placement for Stream Bank Protection . Where geotextiles are placed under water, or in an area where water will flow, the geotextile shall be placed with its machine direction parallel to the directi on of water flow. Successive geotextile sheets shall be overlapped in such a manner that the upstream sheet is placed over the top of the downstream sheet . The geotextile shall be adequately secured to prevent slippage. As the geotextile is placed under wa ter, the backfill material shall be placed on it to the required thickness. The geotextile placement shall not progress more than 50 feet ahead of the backfill placement.
3.Underdrains . When a geotextile is specified to line an underdrain trench, the geo textile shall be placed to conform loosely to the shape of the trench.
4.Geotextile Under Stone Fill . Geotextiles under riprap or stone fill shall be constructed in accordance with the details shown on the Plans and the following requirements . The Contra ctor shall demonstrate to the satisfaction of the Engineer that the combination of the stone fill drop height and the thickness of any sand cushion, when specified or required, are adequate so as not to puncture or damage the geotextile when placing the ri prap or stone fill. Where a sand cushion is used, it shall be a minimum of 6 inches thick, unless otherwise directed by the Engineer. In addition, the stone fill drop height limits specified in Table 649.04A shall apply. TABLE 649.04A – MAXIMUM STONE FILL DROP HEIGHT Type of Stone Fill Maximum Drop Height (in .) Onto Geotextile Onto Sand Cushion Blanket Type I 36 36 Type II, Type III, Type IV, or riprap 0 12 After placement of the stone fill or riprap, all voids that allow the geotextile to be seen shall be satisfactorily backfilled so that the geotextile is completely covered. 6-199 (5) Roadbed Subgrade and Railroad Ballast Separation . The subgrade shall be prepar ed in accordance with Section 203 . Construction vehicles shall be limited in size and weigh t such that rutting of the initial lift placed above the geotextile is no greater than 3 inches deep . Ruts shall not be graded off but shall be filled with material specified by the Engineer such that a minimum 8 inches of cover is kept over the geotextile . Turning of vehicles on the first lift of cover material shall not be permitted . The Contractor shall not use vibratory rollers on the first lift if pumping or dis tortion of the subgrade occurs, as determined by the Engineer.
b.Protection of Geotextile . The Contractor shall not permit traffic or construction equipment to travel directly on the geotextile. The geotextile shall always be protected during constructio n operation s from contamination by surface runoff and construction activities. The geotextile shall be covered with the specified cover material as soon as possible . Uncovered conditions shall not exceed 7 calendar day s. Specified cover material shall be placed on the geotextile in such a manner that the geotextile is not torn, punctured, or shifted. The minimum cover layer shall be 8 inches thick or twice the maximum aggregate size, whichever is thicker, before construction equipment is allowed over the area of the geotextile. The Contractor shall not permit end -dumping of aggregate s from trucks directly on the geotextile.
c.Repair of Geotextile . All geotextile that is torn, punctured, or contaminated during construction shall be repaired or re placed by the Contractor. The repair shall consist of a patch of the same type of geotextile placed over the affected area. The patch shall overlap the existing geotextile a minimum of 36 inches from the edge of any part of the rupture. Where geotextile se ams are required to be sewn, all damaged sheets shall be repaired as required by the manufacturer’s recommendations, unless otherwise shown in the Contract or as directed by the Engineer.
d.Overlaps . The minimum overlap requirements for geotextiles shall be as specified Table 649.04B . TABLE 649.04B – MINIMUM GEOTEXTILE OVERLAP DISTANCES Geotextile Location Minimum Overlap Distance (in .) Underdrain trench lining 12 Under Type I and Type II stone fill 24 Under Type III and Type IV stone fill or riprap 36 Roadbed subgrade stabilization 36 Under railroad ballast 36 6-200 In the event the Engineer determines that the specified overlap is not sufficient, the overlap shall be increased to provide adequate coverage or the geotextile shall be sewn together in the field. If field-sewn, the requirements in Subsection 649.04(e) shall apply.
e.Field Seams . Field seams shall be sewn with polymeric thread, consisting of polypropylene, polyester, or Kevlar, and shall be as resistant to deterioration as the geotextile being sewn. The thread shall be of a contrasting color with the geotextile being sewn, and the seams shall be made such that the stitches are exposed for inspection when the geotextile is placed.
1.Stitching Equipment . The stitching equipment shall be such that it will provide an acceptable lock -type stitch, as recom mended by the geotextile manufacturer and approved by the Engineer.
2.Stitch Requirements . Two rows of lock -type stitching shall be used to make the seam. The two rows of stitching shall be 1/2 inch apart with a tolerance of 1/4 inch and shall not cross, except for re -stitching.
3.Minimum Seam Allowance . The minimum required seam allowance s (i.e. the minimum distance from the geotextile edge to the stitch line nearest to that edge ) are specified in Table 649.04C . TABLE 649.04C – MINIMUM GEOTEXTILE SEAM ALLOWANCES Seam Type Minimum Seam Allowance (in .) Flat or prayer seam, Type SSa -1 1-1/2 J-Seam, Type SSa -1 1 Butterfly folded seam, Type SSd -1 1
4.Seam Type . The Contractor shall obtain the geotextile manufacturer’s recommendations for the type of seam and stitch to be used. If the manufacturer does not provide the foregoing technical information, then the Contractor shall use a J -seam with two passes of a lock-type stitch which places at least three stitches per 1 inch of sewn seam. This seam will be tested as required by these specification s. The prayer seam (flat) may be used for repair of damaged in -place geotextile. 6-201 649.0 5 METHO D OF MEASUREMENT . The quantity of Geotextile of the type specified to be measured for payment will be the number of square yards placed in the complete and accepted work . Slope measurements will be used in computing the area. Measurement will not be made for material used for repairs, seams, or overlaps. Measurement will not be made for material used to replace an installation of fabric that has become damaged, destroyed, lost, washed away, or otherwise ineffective unless authorized by the Engineer. 649.0 6 BASIS OF PAYMENT . The accepted quantity of Geotextile of the type specified will be paid for at the Contract unit price per square yard. Payment will be full compensation for furnishing, transporting, storing, handling, placing, repairing, and removing the mate rial specified and for furnishing all labor, tools, equipment , and incidentals necessary to complete the work . Unless otherwise specified in the Contract, payment for the maintenance of Geotextile of the type specified will not be paid for directly, but wi ll be considered incidental to the specific Contract item . Payment will be made under: Pay Item Pay Unit
649.11 00 Geotextile for Roadbed Separator ................................ ............................. Square Yard
649.21 00 Geotextile Under Railroad Ballast ................................ ............................ Square Yard
649.31 00 Geotextile Under Ston e Fill ................................ ................................ ......Square Yard
649.41 00 Geotextile for Underdrain Trench Lining ................................ ................. Square Yard
6-202 SECTIO N 651 – TURF ESTABLISHMENT 651.0 1 DESCRIPTION . This work shall consist of the preparation of an area and the application of topsoil, grubbing material, sod, seed, soil amendments, and mulch. 651.0 2 MATERIALS . Materials shall meet the requirements of the following subsections: Topsoil ................................ ................................ ................................ ....................... 755.02 Sod ................................ ................................ ................................ ............................. 755.03 Seed ................................ ................................ ................................ ............................ 755.04 Compost ................................ ................................ ................................ ..................... 755.05 Fertilizer ................................ ................................ ................................ ..................... 755.06 Agricultural Limestone ................................ ................................ .............................. 755.08 Liquid Lime ................................ ................................ ................................ ............... 755.09 Hay Mulch ................................ ................................ ................................ ................. 755.10(a) Fiber Mulch ................................ ................................ ................................ ................ 755.10(d) Hydraulic Matrix ................................ ................................ ................................ ........ 755.10(e) Tackifier ................................ ................................ ................................ ..................... 755.10(f) Straw Mulch ................................ ................................ ................................ ............... 755.10(g) Rolled Erosion Control Product, Type I ................................ ................................ ....755.1 1(a) Rolled Erosion Control Product, Type II ................................ ................................ ...755.11(b) Stakes for holding sod shall be rounded or square wooden stakes at least 8 inches long and have a cross - sectional area of approximately one square inch. Stakes of other materials or designs may be used when authorized by the Engineer. Grubbing material for use on stone fill along streams shall consist of grubbed or stripped earth material containing roots of native stream bank vegetation. Grubbing material for use on slopes shall consist of grubbed or stripped earth material containing roots (not necessarily from native stream bank vegetation) which will promote the growth of vegetation. Grubbing material from outside of the project limits shall not contain any invasive plant material found on the state or federal noxious weed lists on file with the Vermont Agency of Agriculture, Food, and Markets. 651.0 3 GENERAL REQUIREMENTS . Turf establishment shall occur during the time periods specified in the Plans, unless otherwise authorized under appl icable permits or directed by the Engineer. All seeded areas shall be inspected by the Engineer for turf establishment within 14 calendar days of application. Areas not showing signs of sufficient growth shall be reestablished at the Contractor’s expense.
Source: Vermont Standard Specifications for Construction, 2024 Edition. Pages 971–975 of 1,380.