Standard Specification for Construction of Geotextiles

　　1、 Preparation before laying

　　1. Foundation treatment: The site should be flat and all debris on the site should be removed.

　　2. Prepare materials and arrange the width reasonably according to the design size.

　　During the transportation process (including on-site transportation from the material storage location to the work site), the geotextile roll must be protected from damage.

　　2、 Laying and overlapping methods

　　1. Manual rolling should be used for laying, which should be smooth, moderately loose, and in contact with the soil surface. The laying personnel should not wear hard soled shoes.

　　2. The paving on the slope should be carried out from bottom to top; The top and bottom should be fixed, and anti slip nails should be installed on the slope, and they should be laid and weighted as needed.

　　3. If there is any damage, it should be repaired or replaced. There are generally two methods for connecting adjacent pieces: overlap and stitching. The overlap width is generally 300mm, and the stitching is usually done using a seam wrapping machine. For areas that may experience displacement, the overlap width should be appropriately increased, not less than 500mm, for laying on uneven ground, soft soil, and underwater. The upstream piece should be laid on the downstream piece at the water flow point.

　　4. The connection with the bank slope and structure should be well bonded.

　　3、 Climatic requirements for geotextile construction

　　1. The temperature should generally be above five degrees Celsius. Geotextiles should be more tense at low temperatures and relaxed at high temperatures.

　　2. The wind force is below level four.

　　When the temperature is too low, construction should generally not be carried out in strong winds of level 4 or above, as well as in rainy and snowy weather.

　　4. In windy weather, when the wind affects the construction of geotextile, large stones or sandbags should be used to press firmly.

　　4、 Backfilling

　　1. Timely backfill the soil material, and the maximum drop height of the backfill soil and stones should not exceed 300mm. Heavy soil and stones should not roll and slide on the slope surface.

　　2. The compactness of the fill should meet the design requirements. After backfilling with a 300mm loose soil layer, it should be lightly rolled and compacted.

　　5、 Construction inspection

　　1. All geotextile sheets and seams must be inspected. Defective geotextile sheets and seams must be clearly marked on the geotextile and repaired.

　　2. Worn geotextiles must be repaired by laying and hot connecting small pieces of geotextile, which should be at least 200mm longer than the edge of the defect in all directions.

　　3. The hot connection must be strictly controlled to ensure that the geotextile patch and geotextile are tightly combined and do not cause damage to the geotextile.