The gas under the geomembrane mainly includes two parts
For plain reservoirs with impervious diaphragms, after the project is completed, the rock and soil body separates the unsaturated soil layer under the membrane from the atmosphere. The gas under the high quality HDPE geocell mainly includes two parts: one is the pore gas in unsaturated soil; the other is the enclosed air between the geotextile and the unsaturated soil during the paving process.
In the early stage of reservoir impoundment, when there is a defect in the HDPE geocell manufacturers, the reservoir water will penetrate the defect of the geomembrane into the membrane water, which will continuously leak the unsaturated soil, which will have the following two negative effects:
- Leakage easily enters the exhaust system of strong sand permeable sand trenches made of coarse sand, flowing along the sand trenches and encroaching on the pore space of the coarse sand. A closed membrane in the exhaust channel of the sand trench produces water resistance phenomenon, which makes this The film cannot pass through the membrane gas ditch, and the check valve exhaust system at normal flow.
- The seepage water continues to penetrate along the unsaturated soil. When the seepage contacts the groundwater, the seepage, low price HDPE geocell and groundwater divide the unified unsaturated soil space under the membrane in the original reservoir area into several relatively closed gas spaces. At the same time, the groundwater level will continue to leak. From the pore space of unsaturated soil, the gas pushes most of the pore gas (a small amount of pore gas is trapped in the form of closed foam), and eventually gathers in the geomembrane membrane in the unsaturated soil pore gas In closed spaces, the formation pressure of natural gas (relative to atmospheric pressure). The pressurized gas causes the geomembrane to swell and deform, which is manifested as the geomembrane floating locally or over a large area. With the continuous infiltration of the reservoir water and the continuous rise of the groundwater level, the upward pressure on the geomembrane is increasing, and the swelling deformation caused by it is also increasing. When the expansion deformation exceeds the deformation limit of the geomembrane, the geomembrane will be damaged by inflation deformation and gas explosion. In addition, the rise of the groundwater level in the reservoir area and the sudden drop in the water level of the reservoir around the reservoir area may also cause the phenomenon of plastic film inflation.