Analysis of Time-Space Effect of Deep and Large Foundation Pit Excavation in Nanjing Silt Area
Based on the deep and large foundation pit excavation project of Nanjing Metro Line 5 and Line 10 transfer station,the time-space effect of foundation pit excavation in silt area is studied.The results show that compared with the general foundation pit engineering,the excavation of deep and large foundation pit in silt area has obvious influence on the surrounding environment,showing significant spatial and temporal distribution characteristics.The surface settlement outside the pit shows a multi-stage variation law with time.In each stage,the settlement rate is the largest when the second layer is excavated,and the overall settlement is large on the long side and small on the short side.Affected by the excavation effect of foundation pit,the transmission range of surface settlement is much higher than 2.2H(H is the depth of excavation).The deformation of the deep horizontal displacement of the soil along the depth direction is'parabolic',and the lateral displacement is large on the west side and small on the east side.The maximum lateral displacement of the wall is controlled within 0.24%H;the settlement of the pipe gallery is obviously different in the long side direction.There is a significant settlement difference in the sideline near the side of the foundation pit.This difference will cause the structure to produce a certain amount of shear force and torque,resulting in structural and waterproof failure.
deep and large foundation pitsoil deformationspace-time effectpipe gallery settlementon-site monitoring
NETL
NSTL
万方数据
