某水电站厂房基坑排水井抽排效果三维有限元渗流分析

摘要

A simplified numerical simulation method was put forward .According to this method ,the sparsely distributed drainage wells surrounding the foundation pit are rearranged as a ring of continuous drainage sink .With this method ,the working condition of the drainage well in the warehouse foundation pit of a hydropower plant during the construction peri-od was simulated with the addition of pumping speed at the bottom of the well as the boundary condition .The simulation results indicate that the underground water head at both sides of the drainage sink is greatly reduced ,the seepage pres-sure in the foundation pit is decreased ,with the increase of the drainage water pumped out from the pit ,the free surface of groundwater in the foundation pit falls ,as well as the infiltration area on the bottom and slope of the foundation pit and the seepage from the groundwater source into the pit .With the drainage measures ,the seepage gradient value of the up-stream and downstream slope is much smaller than that of the natural foundation .%提出了将基坑周边间隔分布的排水井简化为连续分布的排水槽的简化模拟计算方法，同时，通过在排水井井底施加抽排速度边界条件，对某水电站厂房基坑施工期排水井的抽排效果进行了三维有限元数值模拟。计算表明：地下水水头在排水井两侧明显折减，基坑内渗压降低；随着排水井排水量加大，基坑内自由面逐渐下降；基坑底面和基坑边坡上的浸润区也逐渐减小；地下水向基坑渗水量显著减小；同时有排水措施时，上下游边坡渗透比降相比天然地基有显著下降。