In the early stage of reservoir impoundment, when there are defects, the reservoir will seep into the unsaturated soil under the membrane along the defects of the wholesale biaxial geogrid. Continuous leakage will have the following two negative effects:

1. Water leakage is easy to enter. The sand ditch exhaust system composed of coarse sand water infiltration flows along the sand ditch and invades the pore space of the medium sand. The water channel is blocked by the exhaust channel of the closed sand ditch, so that the film under the gas cannot pass through the film under the sand. The groove and check valve exhaust system is usually exhausted.

2. Water leakage continues to penetrate along the unsaturated soil. When seepage water contacts groundwater, the seepage water, high quality fiberglass geogrid and groundwater divide the unsaturated soil space under the original reservoir membrane into several relatively closed gas spaces. At the same time, continuous leakage will gradually increase the groundwater level, squeeze the pore space of unsaturated soil, and make most of the pore gas move upward (a small amount of pore gas is trapped in the closed bubble mode), and the pore gas is accumulated in the geomembrane. Pressurized gas (relative to atmospheric pressure) is formed in a closed, enclosed, unsaturated soil space. Pressurized gas has a top expansion effect on the geomembrane, which causes the geomembrane to expand and deform. The external performance is that the geomembrane floats locally or over a large area, that is, the expansion phenomenon.

As the reservoir water continues to infiltrate, the groundwater level continues to rise, and the polyester geogrid factory price is subjected to increased expansion pressure, resulting in more and more expansion deformation. When the convex deformation exceeds the deformation limit of the geomembrane, a geomembrane is produced. Expansion and deformation of air and explosion occur. In addition, the rise of the groundwater level in the surrounding area of ​​the reservoir area and the sudden drop of water in the reservoir may also cause the geomembrane to swell.