Study On Stability Of Tunnel In Jointed Rock Mass And Safety Construction Technology

Taking the "The Belt and Road" strategy as an opportunity,and there will be a new wave of construction in great long and deep tunnel,our country has paied more and more attention to using the underground space,the environment that is used to build a tunnel will be complicated and changeable,the thing that the tunnel will pass through the jointed rock mass can not be avoidable,so it is that how to take some effective measures to maintain the stability of the jointed tunnel,and ensuring the safty of the tunnel construction will be one of the highest choke point in the tunnel construction.This paper is based on the three dimensional discrete element method,for the tunnel that has passed through the jointed rock mass,and using the method of orthogonal test to analysis the influence of jointed rock mass parameters on the stability of surrounding rock.According to the method of single factor analysis,studying supporting effect on the jointed tunnel by the parameters of shotcrete bolt support,then putting forward the parameters of shotcrete bolt support to apply to different jointed tunnel.Based on practical engineering background,using the unified strength theory to verify the safety factor of tunnel lining,and ensure the safety of tunnel construction,the results of main research are as follows.1.Regarding shear slip zone as a evaluation index of jointed tunnel stability,and use the principle of orthogonal test to determine the level of orthogonal test,then come up with the appropriate orthogonal table.Based on three dimensional discrete element method,build the model of single and cross jointed tunnel,for analyzing the influence on the stability of surrounding rock by rock mechanical properties,joint mechanical properties,and comprehensive properties jointed rock mass,and get the main factors that is affected to the stability of jointed tunnel.2.Building the model of single and cross jointed tunnel with shotcrete bolt support,on the basis of the method of the analysis to the single factor,study the influence on the stability of jointed tunnel with shotcrete support,bolt support,and shotcrete bolt support,get the change rule of guideposts to the stability of jointed tunnel by the supporting parameters.3.Based on the tunnel engineering of Yinpan mountain,aim at layered,massive and fragmentized jointed tunnel,putting forward the reasonable parameters of shotcrete bolt support.Based on unified strength theory,regarding safety factor as a evaluation index,analyzing the lining stress state by the different shotcrete bolt support in jointed tunnel,then get the supporting parameters that can ensure construction safety of the jointed tunnel.