Application of Geomembrane Dam anti-seepage Technology in Hydraulic Engineering Construction
Geomembrane is used for its good anti-seepage effect, and the combination of Geomembrane and geotextile forms a composite Geomembrane. Being punctured by those gravel or sharp objects also prevents the position offset between the geotechnical impermeable membrane and the geotextile. Thus, Geomembrane can solve various leakage problems in hydraulic engineering construction.
1. Application Fields of Geomembrane and its Application in Hydraulic Engineering
Geomembrane can be used on the ground or flat slopes and those places where we need anti-seepage such as common pools, gates, roofs, etc. In recent years, Geomembrane technology has been well applied, such as The dam built in Spain in 1984 is the earliest dam built with Geomembrane technology in the world. The height of the dam is 97 meters, and the dam slope is a 1:13 rockfill slope. It is a stone block, which can prevent the upstream sediment from damaging the dam, and the surface is smoothed with simple cement, and then HDPE high-density vinyl Geomembrane is spread on it, which is what we call geotechnical anti-seepage film. Anti-seepage. The thickness of the lower half of the HDPE film is as high as 2mm, which is double that of the upper half. Then, the film is covered with asphalt, and the steel mesh is laid on the asphalt. Finally, the thickness of the cement concrete is 16 cm. The rules are still working fine. It can be seen that Geomembrane technology has played an important role in improving the quality of water conservancy projects.
2. Basic Requirements of Geomembrane in the Anti-seepage of the Warehouse
According to the different objects used, there are also types of geotechnical impermeable membranes, and there are two common ones: polyvinyl chloride membrane and polyethylene membrane. The polyethylene film has better tensile strength, has a longer service life than the PVC film, and has better water barrier and adhesion effects. It is an ideal anti-seepage material.
Geotechnical impermeable membrane materials generally have the following basic requirements: First of all, the geotechnical impermeable membrane must have no cracks, the adhesion between the main membrane and the non-woven fabric should be good, it has good uniformity and impermeability and air permeability, and it must be thick in thickness. It cannot be less than 0.5mm, and it is best not to exceed its unevenness. The general need is to match the local environmental geology. The Geomembrane on the dam should have good extensibility, be able to adapt to problems caused by changes in geological structure and be able to withstand the test of ground temperature.
3. Specific Problems That Should be Paid attention to in the Construction of Geomembrane Full-Reservoir Anti-seepage Technology
In the structure of the anti-seepage layer of the Geomembrane, the Geomembrane is the main component of anti-seepage, and in the specific anti-seepage process, only relying on the Geomembrane cannot achieve the anti-seepage effect. The anti-seepage layer of Geomembrane is composed of three parts: the Geomembrane itself, the protective layer that protects the Geomembrane, and the supporting layer that plays a supporting role. Damaged things have a certain protective effect, and the support layer is to enable the geotechnical impermeable membrane to be stressed and avoid local damage. The advantages of Geomembrane use are: when the part is damaged, it has the conditions for reconstruction and the construction speed is fast. And it is determined that the amount of materials used in the repair process is large, and the funds are also spent.
The quality of the Geomembrane full-reservoir anti-seepage body must be controlled during the construction process, effective management methods must be formulated for the design requirements and construction conditions, and appropriate information warnings should be given. In the construction process, it is necessary to follow the construction steps, and to establish and improve a comprehensive quality assurance system, so about ensure the construction quality of the project, and control the quality of the Geomembrane. Omit construction, the construction mode of cyclic operation is generally adopted. The connection of the geotechnical impermeable membrane must be welded or bonded with asphalt to prevent the phenomenon of not being pasted. Finally, we should pay attention to the correct welding between the Geomembrane and the membrane, which is also an important link in the construction. The welding speed reflects the progress of the construction, and the quality of the welding determines the entire geotechnical anti-seepage. Thus, it is necessary to control the quality of the membrane to prevent the occurrence of virtual connections and missed connections, so to better ensure the quality of the project.
4. Engineering Case Analysis
4.1 Project Overview
The upstream reservoir handles 12,000 mu of arable land downstream and provides drinking water for a population of 19,000. The upstream reservoir is located in the south of the Junggar Basin, with terrain fluctuations ranging from 750m to 800m above sea level, and the project area is on the back of the structural unit. On the impact plain, the upper half of the dam foundation is a permeable and low liquid limit silt layer, and the thickness of this soil layer is between 12m and 23m. In 2009, the designed total storage capacity was 1.07 million m3 and the dam length was 50m. , the dam height is 11m. The basic shape of the dam is a Geomembrane inclined anti-seepage earth dam. The upstream slope ratio of the dam body is 12.5, and the downstream slope ratio is 12.0. The upstream and downstream slope ratios are different.
4.2 Anti-seepage Design of the Whole Warehouse
The anti-seepage range of the warehouse is the normal Xushui water level, the anti-seepage area is 192,000 m2, the membrane is 50 cm, and a 30 cm soil cushion is set under the membrane. Due to the impact of the warehouse, there is a certain thickness of soil, and the thickness of the soil is satisfactory. As required by the construction, the 30cm soil layer was not replaced, and the construction was carried out using the method of block operation. After digging out the 45cm soil layer, the film laying operation was started. The welding width was reserved first, and then welding and welding were carried out. Omit to weld, it is necessary to grasp the degree of welding. Finally, after the rank is qualified, the next layer of Geomembrane is laid. This method is used to speed up the construction.
The application of water conservancy project waterproofing in water conservancy projects can not only make up for the deficiencies in the water conservancy project on time but also provide a safety guarantee for people’s lives. According to the above analysis of the anti-seepage technology, there are many reasons for the defects of the Geomembrane anti-seepage technology, but in the final analysis, it is because the current technical level is not perfect, as well as the unscientific application and unprofessional personnel, etc. Factors have resulted in the inability to install the anti-seepage technology of the Geomembrane in the whole reservoir. It is also necessary to avoid quality problems caused by improper operation anti-seepage construction of water conservancy projects. In specific practical applications, reasonable anti-seepage technologies should be selected according to different geological conditions, so about achieve the perfect integration of materials and technologies, and give full play to The greatest potential of the Geomembrane anti-seepage technology makes enough preparations for the smooth progress of the hydraulic engineering cylinder.