Reformation & Application On Anti-Seepage Technique By Laying Plastic Vertically

With the development of agricultural and industrial production and living standard of the people, water consumption is increasing year after year and shortage of water is serious day by day. In recent years, many plain reservoirs have been built, but some of them are built in the foundation of silty soil and sandy loam with the problem of seepage deformation at dam toes. In addition, during flood seasons there are problems of seepage deformation at dam toes in some river dikes, which located in the foundation of sandy gravel at the hilly regions. All of these affect the full play to the security and benefit of projects. At present, there are a lot of anti-seepage measures. For example, anti-seepage underground walls can be built through grouting, deep mixing piles, making channel and other methods. They are effective measures in some water projects but with high investment. A new anti-seepage technique had been studied in 1980s,which used plastic membrane, the low-priced material on anti-seepage technique of water projects to reach the purpose of decreasing the cost and meet the demand of anti-seepage.Plastic membrane can prevent infiltration fine, which was used in water projects in 1930s abroad and in the level anti-seepage engineering of channel at home at the end of 1950s. With the widespread application of plastic membrane in 1980s, which is put in use from the level anti-seepage engineering of channel first to lay plastic vertically of reservoir embankment and dike of hydraulic structure. The depth of under construction is from 3～4metres first to 13～14metres now. The suitsoil is from sandy loam to all kinds of soil now.In this paper, the technique is analyzed and discussed from four parts including summary, seepage theory, reformation and application on anti-seepage technique by laying plastic vertically. In the part of summary, it includes the summary and construction method of the technique. In the part of seepage theory, it includes pervious foundation and Darcy's law and seepage calculation. In the part of reformation and application on anti-seepage technique by laying plastic vertically, it includes the status quo at home and abroad, characteristics and reformation of the machine for trenching , anti-seepage design and construction of laying plastic vertically. In the part of application, it includes the examples of engineering aonstruction.