Experimental Study on Influence of Foundation Pit Dewatering on Lateral Pressure Coefficient of Soil

Abstract:

Aiming at the layer 3 mucky silty clay,the layer 4 mucky clay,the layer 5-1 silty clay and the layer 5-2 clayey silt involved in the process of excavation and dewatering of deep foundation fit in soft soil stratum of Shanghai,a study was made on the variation characteristics of the lateral pressure coefficient for the soil layers in different drawdown through the two step consolidation method and K0 test.The test results show that the lateral pressure coefficient value of the clay is larger than that of the silt before and after dewatering.The lateral pressure coefficient of the soil decreases with the increasing of the drawdown,and the lateral pressure efficient value of the layer 5-1,the layer 5-2,the layer 3 and the layer 4 decreases about 3.1%,2.5%,2.3% and 1.3% per meter drawdown respectively.As the drawdown increases,the influence of dewatering on the lateral pressure coefficient is decreasing gradually,and finally the lateral pressure coefficient tends to be stable.In the end,the simple calculation formulas of the lateral pressure coefficient were obtained based on the theory of regression analysis,providing reference for the determination on the lateral pressure coefficient of the soil after dewatering of the deep foundation pit in Shanghai.