Analysis On One Of The Top Wall Bottom Pit In Hangzhou City

The deep foundation pit of subway station are usually in the city’s busy section. Especially in the soft soil area for subway construction, the nature of the soil is complex. Due to the uncertainty of the nature of the soil, the security and stability of pit supporting is more important. Based on related literature and research, this paper takes the deep foundation pit support engineering of a domestic subway station for background and determines the parameters of different constitutive models by laboratory tests.Then by means of theoretical analysis, experimental analysis, monitoring and numerical simulation,the most suitable model is obtained. In the end,through the analysis of the retaining structure of foundation pit,obtain the deformation law and the different faetors impact extent to the deformation in the soft soil area. It hopes that it can be a reference for the construction of the end well foundation pit in Hangzhou area.The main jobs and conclusions are as follows:It sums up the development law of the horizontal displacement of the wall and the ground surface subsidence of the end well foundation pit in Hangzhou area by mean of collating and analyzing the monitoring data.By means of determining different constitutive models in laboratory,Duncan Chang model parameters,Mohr-coulomb model parameters and the parameters of the hardened soil in Hangzhou soft soil area were obtained.By using three kinds of the constitutive models in Midas/GTS NX finite elememt simulation to analyze and calculate the end well segment of the pit and contrasting the calculated results to the monitoring values. The contrast results shows that the Hardening soil constitutive model is more suitable for simulating excavation of foundation pit in Hangzhou area and the displacement of the retaining system,the surface subsidence,the rebound of the pit are close to the reality.Using the Hardening soil model to analyse the different factors which affect the deformation of end well foundation pit. It shows that the thickness of underground continuous wall, the position of bolsters, the quantity of the bolsters,the rigidity of bolsters, overbreak, the depth into the soil of the wall and other factors also affect the horizontal deformation and surface subsidence in different degree. The thickness of underground continuous wall is the most important in all of the effects. The results of the optimization design can guide the construction to a certain extent.