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Geo-textile Fabric (Filter Cloth)
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General
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The area on which geotextile is to be placed shall be constructed to the lines and grades shown on the drawings or as instructed by the Project Manager, Particulars of the geotextile shall be submitted to the Project Manager for approval |
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Geo-textile Fabric
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The geotextile shall be a pervious, non-woven, needle punched fabric, It shall be inert to aggressive conditions that may occur in natural soil or fill, In pllIticular, it must be non-biodegradable, resistant to most soil chemicals and bacteria, unaffected by acids and alkalis within a pH range of 3 to 12 and treated during the manufacturing process to withstand prolonged exposure to ultraviolet degradation,The geatextile fabric shall meet the requirements in Table 7.1.
Table 7.1
The Contractor shall provide the Project Manager with certified copies of the manufacturer's test results, showing average values obtained when the tests listed in Table 7.1 were carried out on the geotextile fabric. During all periods of shipment, land transportation and storage the geotextile fabric shall be protected from direct sunlight, ultra violet rays and temperatures greater than 60°C As far as possible, the fabric shall be maintained wrapped in its protective covering. The Project Manager may reject the geotextile fabric if it has been removed from its protective cover for more than 72 hours prior to use, or if it has defects, tears, punctures! shows deterioration, or damage incurred during manufacture, transportation, or storage. With the approval of the Project Manager, tom or punctured sections of fabric may be repaired by placing a patch of the Same geotextile fabric over the damaged area prior to placing the rock under layer. The patch shall be large enough to overlap a minimum of 1000mm in all directions and shall be stitched up at the edges to the satisfaction of the Project Manager. |
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Placement |
The Project Manager shall be invited to inspect the prepared area immediately prior to placing the geotextile fabric. Fabric may not be placed thereon without the approval of the Project Manager. Geotextile fabric shall be placed manually and ballasted with due care. The Contractor shall make every effort to ensure that no damage is done to the geotextile fabric. Geotextile fabric shall be placed directly on the prepared area. Longitudinal and transverse joints shall be overlapped at least 1000mm. The fabric shall be placed in such 11 manner as to have the least number of longitudinal joints. Wherever such joints occur the upper portion of the fabric shall overlap the lower portion. The lower and upper end of the geotextile shall extend beyond the face line of the toe and crest of slopes respectively. Where the fabric abuts a structure, it shall be folded up against the structure by a minimum of 1OOOmm.
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