西溪电站厂房基坑承压水降压研究及实现

Research on pressure-relief of confined water in foundation pit for powerhouse of Xixi Channel Power Plant and practice

研究对潮州供水枢纽西溪电站厂房基坑承压水降压采用减压井和局部旋喷封底相结合的方案,并利用改进的水平二向有限元程序进行空间渗流场计算,提出减压井布置方法,同时根据基坑开挖步骤,提出减压井运行控制方式,分析了对邻近水闸的沉降影响。对影响降压效果的因素分析表明,控制承压水降压的最主要因素是减压井井口高程。总结了实际施工中承压水减压的情况,并分析了出现局部流土的原因。

The seepage field of the confined water of the foundation pit of Xixi Channel Power-house of Chaozhou Water Supply Project is calculated by the finite element program for two-dimensional seepage in horizontal plane with multi-layer medium; and the layout of relief wells is proposed for the whole pressure reducing combining with rotary-type jet grouting to partly close bottom. Meanwhile according to procedure of foundation pit excavation, it is presented to control and operate of relief wells. And it is analyzed to effect the settlement of adjacent sluices caused by pressure-reducing. According to the analysis of several factors effecting pressure-reducing, it is pointed that the elevation of relief wells is the chief factor to control the results of pressure-reducing. At last, it is summarized to actually operate of relief wells and is analyzed the cause of partly sand falling.