Study On The Stability Of A Deep Foundation Pit Excavation Step By Step

In recent 20 years, top buildings in china is developing with a high speed. Underground space is fully used and underground engineering is developing fast. As a matter of fact, deep foundation is more and more, the problems encountered in deep foundation also are difficult questions to be solved. Now, experience and theoretical methods are used in solving deep foundation problems. Accidents related to deep foundation happens now and then. In this case, it is important to study problems related to deep foundation engineering.This thesis is based on a deep foundation located in Chongqing, China. In this thesis, field monitoring was used based on research results got from other researchers. FLAC3 D was also used in this thesis to monitor the excavating process of deep foundation. The deformation and stress changing condition of foundation pit under the influence of gravity and uniform load was studied. Results got are:Based on using numerical simulation methods in different excavation methods of foundation pit. The results showed: when the foundation is excavated with supporting method, the result is much better, indicating that the deformation of geological profile is much less than that of without support. When excavated without support, the slope is likely to collapse. Therefore, the model should consider the model with support.Earth-retaining pile wall is of great importance to the control of displacement in the process of foundation pit excavation. The deeper excavation of foundation pit, the larger horizontal displacement of the foundation pit. As a result of good effect to defense soil around to collapse, soil arching effect is becoming obvious. This effect can induce the deformation of ground surface.The largest vertical deformation of soil around the foundation pit is 2.5mm; the largest vertical deformation in the inner surface of foundation pit is 1.5mm; the largest horizontal deformation of foundation pit is located in the top surface, which reaches to 5.71 mm and decreases in the direction of outer direction of foundation pit.