考虑渗流影响的基坑水压力计算  

Computation of water pressure on foundation pit considering groundwater seepage

作　　者：罗文林[1] 张在明[1,2] 

机构地区：[1]北京市勘察设计研究院有限公司,北京100038 [2]北京工业大学建工学院,北京100124

出　　处：《工程勘察》2009年第9期1-6,12,共7页Geotechnical Investigation & Surveying

基　　金：北京市科技计划(Y0605010040821);国家科技支撑计划(2006BAJ27B04)

摘　　要：为节约宝贵的地下水资源,北京等城市的管理部门提出在一定条件下必须采用基坑周边隔水,在坑内进行施工降水的政策法规。坑内降水将导致围绕支护结构渗流的发生,从而影响到作用在支护结构上的土水压力。而在一般情况下计算基坑支护结构上的土水压力时,由于没有考虑地下水渗流的影响,因此计算结果可能出现偏差。本文首先探讨了基坑渗流情况下支护结构上水压力简化计算的一般表达式,然后用数值模拟的方法分析了几种典型情况下基坑渗流对水压力的影响,并与简化计算的结果进行了对比,给出了相应的水压力分布模式图。最后通过一个工程实例的计算说明了考虑渗流对基坑水压力的影响。In order to save groundwater resource, some urban management authorities of the big cities, such as Beijing, take the measures such as the impervious supporting structures and dewater in the foundation pit should be used during the retained excavations. Dewatering in the foundation pit will cause groundwater seepage and subsequently influence the water pressure on the support structure. Without the consideration of the groundwater seepage, the calculated value of water and earth pressure on supporting structure would be very different from the reality. In this paper, a simplified general calculating method for seepage water pressure based on the work of the previous research is presented and discussed. Three charts showing the typical modes of water pressure distribution considering the groundwater seepage are proposed from the numerical analysis technique. These numerical results are compared with the above mentioned simplified calculating method and shows very good agreement between the two. Finally, a case of retained excavations is analyzed to illustrate the effect of groundwater seepage.

关 键 词：渗流 渗流孔隙水压力 基坑 

分 类 号：TU432[建筑科学—岩土工程]