三峡船闸高边坡渗流场三维有限元分析

3-D finite element analysis for high excavated slope seepage at Three Gorges shiplocks

三峡永久船闸全部在山体中开挖形成，主体结构总长１６０７ｍ，开挖边坡最高达１７０ｍ。船闸区域裂隙及陡倾角断层比较发育，渗流问题是影响船闸高边坡稳定的关键因素之一。对船闸区域高边坡裂隙岩体中的渗流场进行了三维有限元计算，分析了船闸区岩体开挖前后的渗流分布规律和在开挖边坡岩体中设置不同排水设施的排水效果。分析结果表明：船闸开挖后，边坡岩体内的地下水位比较高，出逸点高出闸底板２０～８０ｍ。在边坡岩体中同时设置排水平调和排水孔幕（２ｍ孔距）的排水效果较好，此外在边坡岩体的顶部和坡面采取表面防渗和排水措施，可以取得更好的排水防渗效果。

The permanent shiplocks of Three Gorges Project are constructed by deeply excavating the rock mass,with their main structures'total length of 1607 m and the highest excavated slope of up to 170 m.In the shiplock area there are comparatively developed fissures and faults of steep dip angle. The seepage problem is one of key factors affecting the stability of high slopes in the shiplock area. 3-D finite element analysis has been carried out on analysing seepage state in the high slopes before and after excavating the rock mass in the vicinity of shiplocks and determining effects of various drainage systems in the excavated slopes. The analysing results show that after the rock mass excavation, the ground water tables behind excavated slopes are still comparatively high,the exit points of seepage flow are 20-80 m above the corresponding shiplock's floors. The drainage system of combining drainage tunnels with drainage hole curtains (hole spacing 2 m)in the slope rock mass works effectively. Additional seepage control measures adopted on the upper part and the slope surface of rock mass may contribute to an even better effect.