In the process of laying geomembrane, it will be affected by many factors, which puts forward higher requirements for the quality control of construction, and improving the quality control of construction is an important prerequisite to ensure the effect of geomembrane laying.
Construction requirements and precautions of HDPE geomembrane:
- The surface of the soil foundation shall be smooth and smooth, compacted and compacted to 95%, and the surface of the soil foundation shall be flat
The integrity is ± 2cm / m2. When laying on the rock foundation, the flatness of the rock foundation surface is required to be ± 1cm / m2
- Cleanliness: within 2.50cm of vertical depth, there shall be no sharp edge sundries such as roots, debris, stones, concrete particles, etc.
- Climate requirements for laying construction: the temperature is 5-40 ℃, considering the expansion and contraction of geomembrane, according to experience, when it is cold, the laying of geosynthetic membrane should be tight; when it is hot, it should be relaxed; however, it should be noted that the high temperature at noon should be avoided in summer.
- Wind and rainy days: the construction shall be stopped when the wind force is more than grade 4 or rainy days; the geomembrane film shall be pressed with sand bags to facilitate the construction.
Laying of HDPE geomembrane Liner:
- It should be extended from the bottom to the high position, not too tight, and 1.50% of the remaining width should be reserved for local sinking and stretching. Considering the actual situation of the project, the slope is laid from top to bottom.
- The longitudinal joints of two adjacent frames shall not be on a horizontal line and shall be staggered for more than 1m.
- The longitudinal joint shall be more than 1.50M away from the dam foot and bending foot, and shall be set on the plane.
- Slope first, then field bottom.
- When the slope is laid, the spreading direction shall be basically parallel to the maximum gradient line.
- Field bottom laying Control: before laying the anti-seepage geomembrane, check and measure the laying area first, and transport the anti-seepage membrane matching the size in the warehouse to the corresponding position according to the measured size: when laying, carry out “push paving” manually in a certain direction.
- Alignment and alignment: the laying of HDPE geomembrane, whether on the slope or at the bottom of the site, shall be smooth and straight to avoid wrinkles and corrugations, so as to align and align the two geomembranes. The lap width is generally about 10cm.
- Film pressing control: use sand bags to press the aligned and assembled HDPE geotech membrane in time to prevent the wind from pulling.
- Laying Control in the anchorage trench: at the top of the anchorage trench, a certain anti-seepage membrane shall be reserved according to the design requirements for local sinking and stretching.
- Longitudinal joint: the uphill section is at the top, the downhill section is at the bottom, and there is enough lap length ≥ 15cm