内隔墙长度对抽水引发基坑围挡侧移的影响

Effect of buttress wall length on retaining wall deflection induced by dewatering

结合实际工程地质条件,开展三维数值分析,研究内隔墙对限制开挖前抽水引发基坑围挡变形的有效性,探究在不同抽水深度与不同围挡嵌固比条件下,内隔墙长度对基坑围挡变形控制效果的影响.结果表明:随内隔墙长度增大,内隔墙对基坑围挡变形的控制效果增强.在不同抽水深度条件下,内隔墙对基坑围挡变形的控制效率不同,当抽水深度大于20 m时,内隔墙长度须大于基坑宽度的0.75倍或者采用全贯通式内隔墙,以取得较好的变形控制效果;当抽水深度小于10 m时,可将内隔墙长度设置为基坑宽度的0.25~0.50倍,预期也可取得较可观的变形控制效果.在不同围挡嵌固深度条件下,内隔墙对变形的控制效率不同,延长基坑围挡嵌固深度能增强内隔墙在抽水深度范围内的变形控制效果.

A series of three-dimensional finite element numerical models were developed,on the basis of practical engineering geological conditions,to explore the effectiveness of buttress wall in reducing retaining wall deflection caused by pre-excavation dewatering.The influence of the buttress wall length on its deformation control effect under different dewatering depth and different penetration ratios were revealed.Results show that the deformation control effect of buttress wall on retaining wall is enhanced with the increase of the buttress wall length.The control efficiency of buttress wall on retaining wall deformation is different under different dewatering depth.When the dewatering depth is greater than 20 m,the length of the buttress wall should be over 0.75 B or set cross wall to totally connect two opposite retaining walls to achieve a satisfactory deformation control effect,where B is the foundation pit width.However,when the pumping depth is less than 10 m,the buttress wall length can be set as 0.25-0.5 B,and at this moment,a significant deformation control effect can be also achieved.Besides,control efficiency of buttress wall on deformation is different under different penetration depth of retaining wall.Extending the penetration depth of the retaining wall can enhance the deformation control effect of the buttress wall in the range of dewatering depth.