Why is geomembrane used in tunnel engineering?
1. Waterproof protection: geomembrane can play a waterproof role, effectively preventing groundwater, surface water and rainwater from penetrating into the tunnel structure. Tunnel engineering often requires a lot of excavation and groundwater control. Geomembrane can provide a reliable waterproof barrier to avoid water erosion and damage to the tunnel.
2. Anti-infiltration and soil retention: Geomembrane is a material with high anti-infiltration performance, which can effectively prevent the infiltration of soil particles and maintain the stability of the soil. In tunnel engineering, geomembranes can prevent groundwater from seeping into the tunnel excavation area, avoid soil loosening and collapse, and thus maintain the stability of the tunnel structure.
3. Isolation and protection: geomembrane can isolate the contact between the tunnel structure and the surrounding environment and play a protective role. For example, geomembranes can keep chemicals in groundwater from coming into contact with tunnel structures, preventing erosion and damage to materials such as concrete.
4. Improve construction efficiency: The use of geomembrane can reduce the requirement for earthwork excavation, simplify the construction procedure, and can be installed quickly to improve construction efficiency. The use of geomembrane can also reduce water loss and groundwater influx during construction, help keep the construction site dry, and provide good working conditions for subsequent construction.
It should be noted that when selecting and using geomembrane, factors such as its quality, thickness, and anti-permeability performance need to be considered to ensure that it can meet the requirements of tunnel engineering and have sufficient durability and reliability. In addition, the construction and maintenance of geomembrane should be standardized and effectively managed to ensure its long-term function and benefit.
How is the geomembrane laid in the tunnel?
Preparation: Before laying the geomembrane, it is necessary to clean up the impurities and irregular surfaces on the bottom and side walls of the tunnel to ensure that the surface is flat and to drain the accumulated water in the tunnel.
Laying of geomembrane: First, a layer of cushion is laid at the bottom of the tunnel to fill in the uneven surface. Then, unroll the geomembrane roll and lay it on the bottom bedding. The geomembrane should be able to completely cover the bottom and side walls and extend beyond the tunnel side walls by a certain width to allow for fixation.
Fixing of geomembrane: Fix the geomembrane on the tunnel side wall with fixing materials (such as high tensile strength strip material, screws or welding) to ensure that it is close to the surface and minimize wrinkles and voids. The spacing and method of fixing materials should be calculated and determined according to the specific situation and design requirements.
Seam treatment: If seams are required on the geomembrane, appropriate seam treatment measures should be taken to ensure the waterproof performance and strength of the seams. Common treatments include thermal fusion welding, mechanical fixing, and gluing.
Further construction: After the laying and fixing of the geomembrane is completed, the subsequent tunnel construction procedures can be continued, such as concrete pouring, structural installation, etc.
When laying the geomembrane, it is necessary to strictly follow the relevant specifications and design requirements to ensure that the quality and function of the geomembrane can meet the requirements of the tunnel project. In addition, the construction technology and technology of laying geomembrane also need to be operated by experienced professionals to ensure the construction quality and effect.