Analysis On Effect Of Deep Foundation Pit Excavation Of Metro Station In Soft Soil Area Of Hangzhou

Most of the subway to pass urban traffic,the environment protection is a lot higher,especially the construction of metro station deep excavation in soft soil area,because of the nature of the soil is very complex,the safety and stability of foundation pit,ground subsidence becomes more and more important.Taking the subway station deep foundation pit in soft soil area in the city of Hangzhou road as the engineering background,using the method of monitoring data analysis,finite element simulation and theoretical analysis of the proposed theoretical formula of ground surface subsidence of soft soil in Hangzhou area,at the same time on the underground subway station deep foundation continuous the wall displacement,supporting the change of axial force and surface subsidence the influence of support material factors such as depth,underground continuous wall buried in different deformation of the retaining structure and ground settlement influence.The main work and conclusions are as follows:(1)Based on the measured data,the horizontal displacement of the wall in Hangzhou soft soil area,the settlement of the ground surface after the wall,the settlement of the building,the size of the support axial force and the variation of the underground water level are analyzed.The research results show that the horizontal displacement of the wall is often affected by soil excavation,the deeper influence on the horizontal displacement of the wall is larger,reflecting the local soil conditions to a certain extent;in the erection or dismantling of the support process,should strengthen the monitoring on the axial force changes,to prevent the sudden increase of axial force or reduce the phenomenon,this will have an important impact on the stability of foundation pit;surface subsidence increases with the increase of excavation depth,the settlement curve and retaining wall displacement,multi parabola or basin shaped distribution;building settlement value decreases with the increase of distance from the edge of the foundation pit;change of underground water level can reflect water effect of enclosure structure.(2)The pit section is analyzed by using the finite element software Midas/GTS,calculated by the deformation of foundation pit were studied by numerical analysis results and numerical analysis of surface settlement lateral displacement of diaphragm wall,also studied the depth of underground continuous wall in different supporting material effect on horizontal displacement and ground settlement,and makes a comparative analysis and construction monitoring data.The results show that the embedment depth of underground continuous wall change mainly affects the central wall displacement on the upper and lower part of the wall is almost not affected;the wall surface subsidence displacement by changing wall depth of amplitude increases;the entire supporting stiffness of the system to a certain extent,can effectively control the deformation of retaining structure.(3)In this paper,the deformation characteristics of deep foundation pit are analyzed,and the retaining wall factors are established with the stiffness,height and width of retaining wall,and the formula of the surface settlement around the deep foundation pit supporting structure in soft soil area is derived.