Stablity Analysis Of Urban Subway Tunnel Cross Section

This paper mainly studies the stability of the subway tunnel cross section,selects the newly developed subway line in Xi'an area.According to the survey data of the completed tunnel route,the stratigraphic lithology parameters are selected and the cross section is selected according to the proposed route.the different cross angles(30°,45°,60°,90°)and the different geologic lithology(loess strata,paleosoltosites,silty clay strata)were calculated by using the ABAQUS software to simulate the finite element simulation.the control variables were used to analyze the parameters,The relationship between the safety distance and the safety distance between the three strata is studied by the control variable method.Finally,the influence of different strength lining concrete on the displacement of the structure is analyzed and summarized.Out of a certain law,hoping to follow the research and reality to help.This article has the following contents:1.according to the "subway design specifications(GB 50157-2003)" requirements of the subway tunnel construction after the deformation must be less than 20 mm requirements as a control standard,divided into different cross-angle,different stratigraphic lithology to try and determine the individual cross-conditions,The safe distance of the loess strata is 0.9D,the safe distance of the paleosolial strata is 1D,the safe distance of the silty clay strata is 1.05 D,the three are different,but both are In the vicinity of 1D,consistent with the existing research results,proved the correctness of the results;2.in other conditions remain unchanged,change the crossing angle to calculate the safety distance.The comparison shows that the decrease of the crossing angle causes the displacement of the structure to increase,so that the safety distance increases,but the increase of the safe distance with the decrease of the crossing angle is gradually decreasing and not linear.The performance in the strata is consistent,so the linear interpolation can not be simply performed in the design of the safety distance at the subway crossing;3.The safety distance of different strata under the same conditions is compared and analyzed,and the safety distance of the loess strata is the smallest,the safe distance of the silty clay strata is the largest,the paleosol is the second,and at different crossing angles,The relationship between the three is not a law,so the relationship between the size of the three can be determined,but the numerical relationship can not be mutually estimated;4.the final chapter of this paper on the concrete structure of the concrete strength of the displacement of the impact of the degree of simulation analysis,can be obtained,the tunnel lining structure of the concrete strength increases,will cause the structure of the displacement is reduced,and the calculation data show that The degree of displacement reduction caused by the increase in strength is weak,so it is not obvious and less economical to reduce the structural displacement effect by increasing the strength of the lining concrete.