The Study Of City Tunnel Construction Safety Evaluation System And Monitoring Measurment

With fast development of national foundation construction and the implement ofdevelop-the-west strategy,the existing traffic system had failed to meet peoplesrequirement for travel,so the nation speed up the use of the new Austrian tunnelingmethod to the design and construction of highway tunnel engineering for remitting theincreasing traffic pressure.But problems in fast development also restricted engineeringprogress.Based on underground ring road engineering of Wuyi road in Chongqing,thispaper applied some methods,local survey、numerical modeling、data analysis and soon，to synthetically evaluate the implement safety of Wuyi road tunnel and study theproblems about measurement and monitoring.Main achievements are as follows:①In city tunnel implement assessment, the material factor （MF），the generalprogress risk factor（F1）,the particular progress risk factor （F2）of city tunnel weredetermined by risk rank method.②Based on rock mass mechanics ranking and risk index assessment method,weput forward ranking hierarchy for city tunnel implement,covering five degrees,from1-5.The weight of factors in the hierarchy was determined by layer analysis method.theinfluencing level of subjective factor on safety degree was measured by compensationfactor.The risk assessment index D=（MF）·F3S1S2=157.54for city tunnel implementwas calculated to assess its implement safety degree,achieving degree two,whichaccorded with actual situation.③The tunnel three-dimensional model was established by ANSYS,and applyingload according to actual situation，then the maximum settlement values of New tunnelvault and Chongqing daily group base and the maximum global incline value of basewas computed，3.397mm,0.731mm，0.081‰respectively，during excavation.④According to actual data for Tunnel surrounding rock deformation，,Surrounding rock instability prediction model was used by cuspidal mutationtheory.and some planes of fracture in Wuyi road tunnel was predicted,showing higheraccuracy rate,with its actual measurement results.