Effect Of Hangzhou Soft-clay On Deformation Of Foundation Pit

In recent years, with the rapid development of underground space development, the depth of the excavation pit deeper and deeper, increasing scale, pit surrounding environment has become increasingly complex. The demand to supporting structure and the surrounding soil stability and deformation is higher and higher, and the supporting structure of the economy is more and more demanded. Especially in coastal soft-soil area, excavation scope and pit bottom lies the thick soft clay, the deformation and stability of foundation is difficult to control. This seriously affect the safety of building structure and underground pipes and other municipal facilities. The bottom of excavation pit of some regions of Hangzhou basically located in the thick layer of soft clay. Bottom distributed soft soil plays a key role for the Foundation stability and deformation. For this type of foundation pit, supporting difficult, high cost, big impact on the surrounding environment. While, in face of the owners considering the economic and security requirements, the design of economic equilibrium and security support programs are necessary. Therefore, the study of the impact of bottom soft soil to the overall stability and the excavation deformation has a strong engineering value.On the basis of predecessors’ research, this article has carried on the further research on this issue, mainly to do the following several aspects:(1) Analysis of deformation mechanism of the ground and supporting structure under the foundation pit excavation.(2) This article introduces the main methods of bottom soil reinforcement, applicability and reinforcement arrangement. Also this artice discusses the effect of different reinforcement forms and reinforcement parameters (cement ratio, transverse reinforcement ratio, reinforcement depth, etc.) on the beformation. It also conclud the reasonable value range of the reinforcement parameters(3) Finite element model of hangzhou metro engineering example is analyzed, calculated the deformation characteristics after excavation, validate the correctness of the foregoing chapter conclusion and analysis of the deformation law of foundation pit.