Influence Of Water Gushing And Pumping On Settlement Of Metro Tunnel

Urban subway is a kind of green environmental protection way to travel,both to solve the problem of traffic congestion,save space on the ground,and can improve the utilization efficiency of time and enrich the mode of travel.With the development of city underground rail traffic in recent years,the problem of settlement of metro tunnel has attracted more and more attention of scholars,but most of the literatures only on land subsidence situation or tunnel deformation modes were investigated separately,around the tunnel stratum settlement research settlement mode of influence on tunnel is still in the initial stage.Among the many factors causing formation subsidence,gushing water and pumping water are the two main factors.Therefore,this paper focuses on the influence on the settlement of tunnel water gushing and pumping were studied by theoretical derivation and numerical analysis on influence of tunnel settlement on the two aspects of ground settlement,provides the theoretical foundation and research ideas for the further studies on certain expansion,has a high theoretical and practical value,can provide guidance for practical engineering.The main work of this paper is:1.Shield construction is influenced by the geological condition of the surrounding environment and construction,when the influx of groundwater can cause great damage to the structure of the subway,poses a great threat to the safety of the construction personnel,so the study of tunnel settlement caused by leakage and water gushing is of practical significance.This paper analyzes the flooding accident of the shield interval of Nanhe village to Dabi village of Tianjin Metro Line 6,the settlement both of ground surface and tunnel structure were simulated.By comparing the measured data and the actual monitoring section,thus obtains the value of settlement in area which is not detected thus obtain the influence scope of the flooding accident.2.Based on the theory of beam on elastic foundation,using the tunnel equivalent stiffness model,using the four order constant coefficient non homogeneous linear differential equations of mathematical theory,obtain the analytical solution of longitudinal settlement of tunnel under cosine formation displacement mode y=acosωx,with the mathematical theory and engineering practice combined,considering that the elastic foundation with same foundation coefficient,within the normal range,the smaller beam stiffness is,the greater final settlement value will be,then use the theory of material mechanics,directly calculate the angle of deformation curve and the bending moment and shear force of tunnel torus.Finally,it analyzes whether the obtained basic mechanics quantity is in accordance with the general theory of elastic foundation beam,and then compares the trend of basic tunnel mechanics volume under different foundation coefficients and different flexural rigidity,and analyzes the influence of final settlement size of tunnel after pumping factor.3.Abaqus finite element analysis software was used to simulate the settlement of tunnel under ground subsidence caused by pumping water.Comparing the settlement of ground with or without tunnel,it was found that the subsidence value of subsidence with tunnel was higher than that of pumping only,and the soil above the tunnel will have a greater settlement of the formation of the surrounding settlement of the regular settlement Funnel.During the pumping process,the pore water pressure of the soil layer decreases obviously,the soil water collects to the center of the pore pressure funnel,the upper strata undergo drainage and consolidation,and the ground surface settles.