Abstract:

Aiming at the seepage at the initial cofferdam foundation of Qingtian water conservancy project, the finite element method is adopted to analyze the influence of seepage treatment depth on the effect of seepage prevention. Combined with the factors such as the economy, rationality and feasibility of the scheme, the economical treatment depth is determined. The study result shows that as the decrease of the treatment depth, the seepage prevention would be less effective. Further, the seepage is closely related to the geological conditions where the bottom of high-pressure jet grouting wall locates, namely the lower permeability of the geology, the less seepage. By comprehensive study, the depth of 23 m is adopted.

Key words: Qingtian water conservancy project, cofferdam, cofferdam foundation, high-pressure jet grouting wall, effect of seepage prevention

摘要： 利用渗流有限元方法计算分析青田水利枢纽初期及一期上下游围堰堰基防渗处理深度对防渗效果的影响，并综合考虑临时工程造价的经济性、渗流控制的合理性、施工方案的可行性等因素来研究堰基防渗处理的经济深度。研究认为，随着防渗处理深度的减小，防渗效果逐渐变差，且基坑渗流量增加幅度与高喷防渗墙底部所处地基的渗透性密切相关，所处地基的渗透性越小，渗流量增加幅度越小。经技术经济比选，认为防渗墙底高程达到-23 m能够满足围堰安全及工期要求，且造价比较经济。

关键词: 青田水利枢纽, 围堰, 堰基, 高喷防渗墙, 防渗效果