Study On Stability Of Foundation Pit Under Complicated Environment Loads

With the rapid development of urban economy,the pressure of city traffic is more and more significantly,in order to satisfy people's daily life and travel.in the city center the land is shortage,so the full development of underground space has become an inevitable trend,such as the subway,river tunnels,underground garages,underground passages,underground stations etc.Underground space development scale is getting bigger,so now the deep pit is deeper and bigger or other characteristics.And also in the dense city center,the surrounding complicated environment influence the construction of the pit is enormous,it should be strictly controlled,otherwise a huge security risk to the city.To alleviate traffic pressure of riverbanks in Nanchang,Jiangxi.The tunnel of cross Gan River in which one connection the old and new city is constructed in Nanchang at present,scilicet honggu tunnel.In the construction of major projects honggu tunnel,the east coast deep pit that riverside is large and deep,and it exist bias at around.The influence which pit heap load and vehicle dynamic load to riverside deep Foundation stability can not be ignored.And the currently,the relevant norms of the bias foundation design and construction in vehicle dynamic load is not detailed provisions.Therefore,to carry out one research which internal force and deformation of supporting structure of riverside deep foundation pit in bias effect,it has a very important practical significance,and it can provide a reference for future similar engineering design and construction.In this paper,Retaining structure stability of riverside bias deep excavation which in pit heap loads and vehicles dynamic loads were studied,which use four methods,such as comprehensive research,theoretical research methods,numerical simulation and field monitoring.including the following major elements:(1)Combine the project characteristics of hong-gu tunnel east coast deep pit,it is a long arcuate ground wall as deep foundation supporting structures.At present,in most cases,we considering the state of the ground wall as straight,without taking into account ground wall arcuate state.Based on this,from the classic shell theory,we established arcuate ground wall theoretical model of deep foundation,and then deduced the relationship of between stress and strain,then export the balance differential equations of arcuate ground wall,combine the arcuate ground wall boundary conditions,I obtained the displacement of arcuate ground wall by using mathematica software;For each boundary condition,the result is different,so before the calculation of the specific project,it is necessary to correctly judge the boundary condition of the arc wall.(2)Using numerical finite element software Abaqus to simulate the excavation,Byanalyzing the acts of pile load and dynamic load case around foundation,I analysis envelope size deformation situation of the foundation pit,I obtain the results of preloading recommendations threshold and the vehicle dynamic load area from the pit and the proposed size of the value,and analysis the situation of the pit heap load and dynamic load on the stability influence of foundation structure;(3)To carry out the monitoring in which hong-gu tunnel east coast riverside deep excavation,To collate and to research the monitoring data.Comprehensive theoretical data and ABAQUS numerical simulation data to compare and analysis the features of this structure deformation of deep foundation pit,To achieve information dynamic construction.