复合防渗结构在调节池工程中的应用

Application of composite anti-seepage structure to construction of regulation pool

亦庄调节池工程是北京城市东南部地区的重要水利枢纽，其池底基础多为中细砂层，存在渗漏问题；场区周边地区曾经为非正规垃圾填埋场，地下水有一定污染，因此需要采取可靠有效的防渗措施以防止内水外渗和外水内渗。经多方案比选，推荐采用改性砂质粉土与土工膜相结合的复合防渗结构，可使年渗漏损失量降低90％，大大提高结构的抗渗性能。通过配比试验研究，确定改性土的水泥掺量为5％，可减小渗透系数4～6倍。

Yizhuang Regulation Pool is an important water control project in the southeast region of Beijing, of which most part of the bottom foundation consists of medium-fine sand with the problem of seepage, furthermore, the areas around it are some abnormal refuse landfills with a certain pollution of groundwater, thus reliable and effective anti-seepage measures must be taken for preventing the inward and outward seepages therein. Through the comparison made on several alternatives, a composite structure combined by both the modified sandy silt and the geomembrane is recommended herein, By which not only the annual seepage loss can be lowered by 90% , but the anti-seepage performance of the structure can be largely enhanced. Through the relevant study on the mixing test, the cement mixing content of 5% is determined, which can reduce the permeability coefficient by 4 6 times.