Abstract:The reverse construction method of deep foundation pit is one of the common construction methods for the excavation of deep foundation pit. By establishing a three-dimensional numerical model of reverse construction of deep foundation pit in composite strata, the deformation characteristics of soil and supporting structure of deep foundation pit by reverse construction method are analyzed. The research results show that (1)the uplift at the bottom of the deep foundation pit by reverse construction method gradually decreases from the center of the foundation pit to the end. The deformation is mainly concentrated between the column piles. The extrusion combination of the column piles effectively inhibits the soil deformation of the foundation pit.(2)With the increase of the distance from the excavation boundary of foundation pit, the ground surface settlement gradually decreases and finally tends to 0. The maximum ground surface settlement on the long side of the deep foundation pit by reverse construction is 1.97 cm, and the maximum ground surface settlement on the short side is 2.64 cm.(3)With the increase of excavation depth, the horizontal displacement of the diaphragm wall increases first and then decreases. When the depth of the diaphragm wall is about 7.0 m, the curve of the horizontal displacement appears an inflection point, and the horizontal displacement of the diaphragm wall gradually decreases and finally tends to 0.
