Analysis Of Settlement Of Ground Surface Induced By Dewatering In Foundation Pit

With the rapid development of National Economy and Urban Constructive of our country, usages of high altitude and underground space are increased significantly. Most of deep excavation has relationships with the dewatering. The influence of dewatering on the settlement of ground surface surrounding a pit is one of the key problems in excavations. However, there is no a reasonable and reliable evaluating method so far.The technique of dewatering and the analysis of settlement of ground surface induced by dewatering in foundation pit is firstly discussed in detail, and the research focus of the settlement of ground surface induced by dewatering in foundation pit is also summarized.Second, it introduces the badly affect of the groundwater in foundation pit. And the method as well as the applicable conditions of dewatering in foundation pit,the function of dewatering in foundation pit,and its effect on the surrounding environment was summarized.And then, it analyzes the deformation mechanism of the soil under the dewatering and the influencing factors of the earth's settlement. It concludes existing fundamental theory of settlement of ground surface induced by dewatering in foundation pit. By mathematical analysis, a groundwater movement equation considering water expansion, aquifer compressibility and solid grain movement due to groundwater pressure decline is established. Then it analyzes the effective stress under the dewatering at the base of total stress is changeless and changeable.For the calculation of land subsidence caused by pit dewatering, This paper at the base of summarizes the calculation of land subsidence caused by pit dewatering always be used in engineering, it analyzes the problem of the calculation of land subsidence based on elastic theory. Then it improves this methods, and the two methods is applied to practice foundation pit and observed value in one example foundation pit, and are in good agreement with the observed results. Meanwhile, engineering method was proposed to reduce the damage to surroundings resulted from pit dewatering.Eventually, the problems requiring further studies are discussed.