Study On Optimization Of Deep Foundation Pit Excavation And Support In Bridge

With the gradual strengthening of national economic strength,Guizhou city bridge construction is also in a rapid development stage,and the face of increasingly scarce urban land,in order to reduce the city suspension bridge foundation excavation surface,the anchor foundation depth More and more deep,therefore,the bridge foundation pit project size and volume is getting bigger and bigger,the design and construction difficulty also increases.In this paper,combined with the engineering case in Guizhou,the selection of foundation pit,deformation of foundation pit excavation and optimization design of foundation pit support are of great significance.In this paper,the foundation pit supporting structure of Moutai No.4 Bridge(pedestrian bridge)in Renhuai City is taken as the research object.Firstly,according to the engineering survey,engineering geology and hydrological condition,failure experience of excavation and evaluation of expert evaluation Supporting the Pile Support as the Supporting Scheme of Moutai Foundation Pit.Secondly,the displacement settlement of the foundation pit and the construction of the building is monitored,and the change law is studied.The numerical simulation of foundation pit excavation is carried out by MIDAS / GTS NX finite element software,and compared with the monitoring data.Finally,the rule is summarized,which provides the basis for the optimization design of lining and supporting structure.Compared with the results of simulation and monitoring,it can be seen that there are some differences between the simulated data and the field monitoring data when the 2-meter-thick lining is used,but the deformation and settlement of the foundation pit are basically the same,and the maximum deformation is less than the foundation pit Monitoring the alert value,so the pit excavation process with sufficient safety.In order to further optimize the support structure,through the use of lining thickness of0.5 meters,1.0 meters,1.5 meters,respectively,and whether the support in the case ofanalysis.The maximum displacement of the foundation pit is 35.0mm,although it does not exceed the warning value,but it is close to the warning value,and the excavation monitoring data of the foundation pit are slightly larger than the simulated value.,So undesirable;liner thickness of 1.5 meters and no support,the maximum displacement of the pit is 22.7mm,much smaller than the warning value.So the lining thickness of1.5 meters and no support of the support structure,you can ensure the safety of excavation.In short,this study provides the basis for the optimization and improvement of foundation pit excavation support structure under similar geological conditions.