| Different kinds of methods are used to study the deformation law of foundation pit and the interaction between building and pit where the adjacent buildings exist.In the study a deep foundation pit which located in Tianjin Binhai New Area is taken to simulate.The results of the work can be provided reference for the design and construction of the future similar deep foundation pit.The research achievements are as follow:(1)Based on the analysis about the deformation law of foundation pit,and summarize the characters of the stress and deformation when buildings exit near the pit and a few factors are gotten which effcte the deformation on both the pit and building.Find the main influencing factors are the deformation of the soil caused by the additional stress of the building,and then make the supporting wall displacement and support structure stress increases,and make the neven settlement of buildings increased.(2)FLAC3D V5.0 is used to simulate the excavation and calculate the deformations of deep foundation pit and its adjacent building.Comparing the simulated results and the monitoring data,both the method and its model are proved to be reasonable and it has a enough reliability.(3)Building models with different height and types of foundation are designed to calculate the displacement of the supportting structure in different construction conditions.The result shows that the existing building will reduce the displacement of the supportting structure in shallower soil and enlarge it in deeper soil.The change is reverted triangle from up to dowm.The main factors which effect the deformation of supporting structure changed from soil and the structure itself to the loads of the building when the building becomes closer and higher,which means the change of distance from pit to building and the building height.The building does not change the distribution of deformation,which means that the maximum of deformation presents in the simular position vertically,which is close to bottom of excavation pit.(4)By adjusting the distance between building and foundation pit,building height and other parameters,the relations between building and the ground settlement are anylized.The results show that the influence of the building on the ground settlement around the foundation pit including horizontal beneficial effect and vertical adverse effects.With the building closer to the foundation pit the dominant influence gradually changes from benefit to adverse.It is also found that the existence of the surrounding building make the other side of the ground surface subsidence "uplift effect".(5)By simulation to calculate the settlement of the buildings,the relationship between surrounding building settlement and foundation pit excavation is gotten.the results show that the maximum settlement and differential settlement caused by deep foundation pit excavation relates to 2 factors mainly,which are the distance between the foundation pit and the building and the height of the buildings.The closer the distance is,the greater the settlement,the higher the building is,the greater the settlement gets.And the largest difference settlement appears when the distance between the building and the foundation pit is equal to the depth of the foundation pit.(6)By the analysis to the relationship between building foundation and retaining structure of foundation pit,a influence mode is put forward.In this model,the influence of building foundation on the retaining structure of foundation pit is similar to the stress diffusion angle of foundation,at the same time,it is related also to the depth of the foundation,the excavation depth of the foundation pit and the distribution of the soil layer.As soon as the retaining structure of foundation pit aproach this model range,the deformation will increase significantly.(7)A additional deformation influence line model is put forward in this paper.it can be used to perform additional deformation of foundation pit with the influence of surrounding building. |
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