Deformation Performance Of Excavation Engineering In The Soft Ground

The excavation engineering incorporates the geotechnique and structure engineering into an organic integrity. Excavation produce all kinds of deformation, including horizontal movement, surface settlement and upheaval in the bottom of the excavation. Deformation of excavation is effected by many factors, such as soil character,form of retaining structure, manner of excavation, groundwater and surrounding environment. During the progress of excavation in soft soil area, how to effectively control the deformation and make the project safe and economical is an important task of engineerer.This thesis is based on practical project, taking the excavation engineering of The people's hospital in Chenghai district and First Affiliated Hospital of Shantou University for example, in-situ monitoring the retaining structure and nearby condition during the period of excavation, making deep research on the deformation of retaining structure and surrounding environment, also analyze the influence which the construction procession effected on deformation of excavation, here obtained some practical achievements. Combining with the typical deformation of excavation in Shantou area, a feasible way is put forward for excavation, so as to provide some reference for the similar projects in Shantou.With practical examples of project, the finite element program PLAXIS V8 is used to make numerical analysis and calculation for single-row pile, double-row piles and braced system with single-row pile, come to the conclusion of deformation's character for different retaining structure. By considering other factors which had effect on internal force and deformation of retaining structure, such as the rigidity of the piles and top beam, the distance of the double-row piles, together with the comparison of numerical results, proved that double-row piles have superior performance, therefore, to choose reasonable pile diameter,top beam height and distance of the double-row pile can keep the relations between structure stability, deformation and cost decrease to a better balance. Here some positive results are obtained which can be a reference for the theory and practice.One reasonable 3D calculation model which built based on PLAXIS 3D FOUNDATION shows that excavation has spatial effect and corner effect. Through simulating and analyzing different excavation processes, it proved that the way of excavation by steps and concrete bottom plate by steps can realistically simulate real excavation deformation. So it's quite necessary to do 3D finite element analysis in excavation engineering, and has important practice meaning for excavation project's numerical analysis and optimize design, also assures the security and stability of excavation. In the last chapter, connection with thesis's conclusion and problems in engineering, we put forward some suggestion and expectation for future work.