Field Dewatering Induced Ground Settlement Calculation Based On Effective Stress Increment Method

Differential settlement of the subgrade induced by ground dewatering is the main reason caused the foundation accidents. This study is jointly supported by the National Natural Science Foundation (50508012), Innovation and Technology Harbin Youth Research Foundation (2008RFOXG058). Based on incremental stress theory and the field monitoring data, a study on the foundation differential settlement mechanism induced by dewatering was done in a foundation pit in Harbin. as well as the main influence parameters and calculation models. The primary research work of this paper as follows:Firstly, Based on Biot's consolidation theory, a mathematical model coupling groundwater seepage and stress was established according to the law of conservation of mass, the Principle of effective stress and the Darcy's law as well as the equilibrium differential equations, in addition, this study provides the solution to the mathematical model by Finite Element Method(FEM).Secondly, the stress variation in different aquifer and the trend of the density of the soil caused by dewatering in the dewatring field are investigated. in addition, The influence law of buried depth of foundation on the settlement and incline for the existing structure surrounding the foundation pit is obtained .And further some effective measures are proposed to alleviate the total and the difference settlement of the ground.Thirdly, according to the calculation model above, a 3-D finite element analysis coupling fluent and solid was conducted in a foundation pit engineering in Harbin based on the actual dewatering conditions. Through careful analysis of the difference between the monitored results and the calculated results. A significant law of excavation unloading will increase the difference settlement is revealed.Finally, the thesis summed up the contents of this paper and proposed some objects to be explored in the future.