Study of PFC Numerical Simulation of Soil Nailing Wall Support Excavation

A three-dimension soil nails support excavation particle simulation model is established by the software of PFC3d which is based on discrete element method(DEM).The contrast of deformation and stress during excavation between PFC3d numerical model with and without soil nailing is analyzed in order to investigate laws of excavation with soil nailing and mesoscopic mechanism of soil nailing.Great difference exists in deformation mode and level between excavation with and without soil nailing because the effect of soil nailing.The deformation of wall,foundation pit and settlement of excavation with soil nailing is smaller than that without soil nailing.Especially the deformation mode of wall with soil nailing which appears a special mode with small deformation on the top and at the bottom of wall and big deformation in the middle of wall.Finally,the mesoscopic mechanism of soil nailing is analyzed.The pullout contact between soil and nailing is not only factor for the excavation support;the soil arching is the most important factor for the soil nailing wall support excavation.The mesoscopic mechanism and PFC simulation study is expected to be a new approach for soil nailing wall support excavation research.