Research On The Foundation Pit Precipition Of Jin-yu Road Underpassing Jin-shan Railway

As the Chinese transportation construction are built expansible at a large scale, the new linepassing below the existing railway is more and more and the crossing mutual influence betweendifferent lines becomes inevitably. The settlement and deformation of the existing railwayroadbed and tracks is caused during the new tunnel construction passing through. It not onlyaffects the safety of the new tunnel construction and surrounding environment, but also affectsthe safety of the existing line. The serious settlement and deformation will cause of both theexisting railway and road damage and safety accidents and cause large economic loss. Therefore,it is very import that studying on the settlement and deformation of the existing embankment’sprecipitation Construction during the new tunnel construction passing through.At first, the paper describes the importance of engineering precipitation and the concept ofrelatively best precipitation scheme, and then review of the domestic research of constructionprecipitation and calculated from the theoretical analysis of foundation pit dewatering, sitemonitoring, finite element numerical analysis, expounded the theory of seepage analysis,introduced and summarized based on FLAC3D fluid-structure interaction analysis. Whatmentioned above is the theoretical.The main research works of this paper are as following:1.Base on the understanding of the actual project overview, the U-groove construction lengthof the tunnel under the bridge is selected as the analysis object, and then set of six differentconstruction length of the U-groove, six different precipitation conditions;2. Using3-D finite-difference numeric simulation software FLAC3D, simplify the analysisof the soil parameters and the initial stress, establish3-D ground settlement model, numericalsimulation analysis of different precipitation scheme. Then we obtain the vertical displacementcontours of ground, the vertical displacement contours of railway embankment, the vertical displacement contours of railway embankment’s edge, the vertical displacement contours ofrailway embankment at a cross-section, the subsidence curve of railway longitudinal center axis,the subsidence curve of railway embankment at a cross-section and the time curve between nodevertical settlement and precipitation stable equilibrium.3.Combined with the relevant regulatory requirements for the simulation analysis of theoverall results, we can first get out the length of the U-groove construction should be controlledin about100m at the distance on both sides of the railway embankment, and then useoptimization theory to optimize the design of the length of the U-groove construction, we candetermine the final plan is that building80m U-groove and130m long waterproof curtain at theboth sides of the road and bridge body.The research results are important not only fort the relevant engineering program but alsofor the similar future project.