Research on Auxiliary Pile Group’s Impact to Foundation Pit’s Horizontal Displacement and Analysis on Pile Group’s Equivalent

Abstract

Auxiliary pile group closed to foundation pit can improve the stiffness of soil mass and decrease foundation pit’s transformation effectively to guarantee foundation pit’s stability. Drucker-Prager model is used and matched with Mohr-Coulomb model’s circumcircle, which can solve the problems of uncertain viscoplasticity strain rate and discontinuous in cones vertex, compared with Mohr-Coulomb model. Also, numerical simulation software FLAC3D is applied to help analyze foundation pit’s horizontal displacement caused by auxiliary pile group, and sensitivity analysis is done about pile spacing and stiffness. The calculation results compared with monitoring data show that Drucker-Prager model is appropriate to simulate foundation pit. Stiffness of soil mass can be improved obviously by auxiliary pile group. Auxiliary pile group of CFG mainly reduce foundation pit’s upper horizontal displacement while bored piles mainly cut down deep layer’s horizontal displacement of soil mass. The results can provide references to both design and management of foundation pit.