Exploration and Practice of Geomembrane in Anti-seepage Engineering
Geomembrane is a waterproof barrier material based on high molecular polymer. It is mainly divided into low-density polyethylene (LDPE) wholesale LDPE geomembrane and high density polyethylene (HDPE) LDPE geomembrane for sale. LDPE geomembrane manufacturers having a thickness of 0.8 mm or more is also referred to as a “waterproof board”. Since its inception in the early 20th century, it has been widely used in various anti-seepage projects at home and abroad, but there are problems in the construction of paving.
In the 1980s, in order to solve the problem of the suitability of wholesale LDPE geomembrane laying construction, Chinese engineers put forward the idea of “composite LDPE geomembrane high-quality” and obtained a positive response from domestic LDPE geomembrane high-quality manufacturers, and then produced “tension, tear resistance, bursting, etc.” The new LDPE geomembrane for sale products with high physical and mechanical performance indexes are widely used in the fields of anti-seepage, isolation, reinforcement and anti-cracking reinforcement in domestic engineering construction.
2. Problems in geomembrane applications
LDPE geomembrane high-quality is widely used, and it gradually exposes many problems.
2.1 Defects in the production process and construction welding
(1) Due to the constraints of the heat fusion process and the influence of the process environment, in the process of heat fusion, the LDPE geomembrane high-quality generally has thermal burns, especially the structure of the second film, so that the wholesale LDPE geomembrane defects that play a key role in seepage prevention are difficult to be effectively discovered, and There are impurities involved in the heat fusion process to form plaques.
According to the actual investigation, the manufacturer found in the material testing that the geotextile fiber generally enters the LDPE geomembrane for sale by more than 0.1mm during the thermal fusion process between the LDPE geomembrane high-quality and the geotextile. The structure of the second cloth and the membrane is required to be thermally fused on both sides of the membrane body, and the effective thickness of the LDPE geomembrane manufacturers will be lost by more than 0.2 mm.
(2) The LDPE geomembrane high-quality appearance indicators specified in the national standard “German synthetic material polyethylene LDPE geomembrane for sale” (GB/T 17643-1998) are shown in Table 1.
According to the requirements of Table 1, a wholesale LDPE geomembrane has a width of 6 m and a length of 60 m, which allows a perforation repair point, 10 impurities and a stiff block to occur per 180 m2 of LDPE geomembrane high-quality. For example, if a reservoir has an anti-seepage area of 5.04 million m2, 28,000 perforation repair points, 280,000 impurities and stiff blocks are allowed.
At present, LDPE geomembrane for sale thermal fusion welding technology has been greatly developed, and dual-track automatic welding has been widely used. However, due to the construction environment, overheating and low heat welding may occur. The former will lead to a weaker physical and mechanical index of the weld than the wholesale LDPE geomembrane base metal, which will result in poor welding and water leakage. What is more serious is that the whole anti-seepage is spliced by a large number of splits. The double-track automatic welding is difficult to meet the quality requirements at the “ten” and “d” nodes of many splits. For this kind of defect, the hand-held hot air blower is usually used. Reinforcement, it is easy to cause the weld hot melt to be too low and too high, which becomes the weakest point of the anti-seepage system LDPE geomembrane manufacturers, and the reinforcing effect is difficult to evaluate.
2.2 Problems with construction and installation damage
(1) LDPE geomembrane high-quality is a low-strength, flexible material that is easily damaged by tools during loading and unloading.
(2) The stacking and laying process is easily damaged by the sharp objects on the site.
(3) Improper construction of the construction personnel will cause damage to the wholesale LDPE geomembrane.
2.3 Anti-seepage problems caused by geomembrane defects
The defects of the composite LDPE geomembrane for sale will definitely bring leakage, immersion and stability problems to the anti-seepage project. More serious is that due to the randomness of the composite LDPE geomembrane high-quality defect point, the leakage liquid is randomly connected with the groundwater, which causes the wholesale LDPE geomembrane gas ups and damages and groundwater pollution problems.
3. Application of geomembrane
In view of the frequent problems of LDPE geomembrane for sale anti-seepage engineering, the following solutions can be used:
3.1 Membrane cloth separation
Membrane cloth separation means that the LDPE geomembrane high-quality and the geotextile are laid separately, welded by themselves (stitched), and independently tested and accepted. The engineering practice shows that after the film cloth is separated, the wholesale LDPE geomembrane defects can be effectively remedied, the geotextile sewing is convenient and reliable, and the reservoir anti-seepage requirements can be effectively guaranteed.
3.2 Multi-membrane structure
The multi-membrane structure is different from the single-membrane structure currently used LDPE geomembrane manufacturers. Under the condition that the total thickness of the anti-seepage film is constant or increased, the single film is divided into two layers or three layers which are laid on each other.
The principle is:
(1) LDPE geomembrane manufacturers defects that overlap each other are difficult to overlap, and the diameter between the defect points can be effectively extended. (2) The water body infiltrated by the upper LDPE geomembrane for sale defect point forms a water film between the LDPE geomembrane for sale overlapping with each other. Under the vicious and adsorption of water, the seepage resistance between the laminated membranes increases, further restricting Seepage loss. (3) The more the number of layers of wholesale LDPE geomembrane that are superposed, the more favorable it is to improve the anti-seepage effect.
In order to ensure the quality of welding, the film thickness of each layer should not be less than 0.2mm.
3.3 node reinforcement
On the basis of membrane separation and multi-membrane structure, key reinforcement measures are taken for numerous “ten” byte points and “d” byte points LDPE geomembrane manufacturers.
Table 1 LDPE geomembrane manufacturers appearance indicator table
4. Application practice of geomembrane
In order to overcome the shortcomings of the composite wholesale LDPE geomembrane, the Dagu Reservoir on the east line of the South-to-North Water Diversion Project changed the composite LDPE geomembrane for sale design to the membrane cloth and received good results.
In order to further overcome the shortcomings of the large-scale LDPE geomembrane for sale anti-seepage project, the east line supporting the project of the South-to-North Water Diversion Project was designed in the reservoir bottom anti-seepage project of the Dongping Reservoir (Ruyi Lake) in Zhangping, using “membrane cloth separation, double-membrane structure, and node reinforcement”. “Technology, combined with the overall detection and gas-lifting technology of wholesale LDPE geomembrane anti-seepage engineering, received the effect of “basic dripping without leaking”. The LDPE geomembrane high-quality seepage section (partial) of Dongxing Reservoir is shown in Figure 1.
Fig.1 LDPE geomembrane manufacturers anti-seepage section (partial) diagram of Dongxing Reservoir
5. Conclusion recommendations
(1) It is not suitable to use composite LDPE geomembrane for sale for important anti-seepage projects.
(2) The anti-seepage LDPE geomembrane high-quality should adopt the technology of “film cloth separation, multi-membrane structure, and node reinforcement”.
(3) Pay attention to the gas rise problem of wholesale LDPE geomembrane anti-seepage project and take corresponding measures