Study On The Technology Of Soft Rock Tunnel Construction Under Complex Geo-stress

To be in Baozhen tunnel on Yichang Wanzhou railway as the engineering background,aiming at the complicated stress conditions of tunnel buried depth,topography and geology,serious bias and soft surrounding rock of low strength and poor stability of the surrounding rock rich in groundwater and other unfavorable factors,in-depth research and analysis of the technical characteristics and key construction deformation of soft rock tunnel under complex stress conditions.Combined with the in-situ stress test results,using FLAC-3D finite element software,regression of the Baozhen tunnel regional stress field data,obtained under different conditions of tunnel surrounding rock initial stress,the fitting results verified the rationality of stress,infer the tunnel area is very high to geological disasters of rock burst and soft rock large deformation may occur force and in the tunnel construction,based on further analysis of the stability of surrounding rock during tunnel construction.Through the establishment of safe tunnel construction monitoring system,accurate and timely access to the different sections of the tunnel construction process of surrounding rock and support structure deformation characteristics and the actual stress state of tunnel right hole is the supporting structure of the safety was evaluated and optimized parallel heading support structure of section form and construction parameters.The initial support scheme,initial support reinforcement and two lining proposed construction time.According to the characteristics of high stress along the tunnel with large deformation of soft rock layer bias,mechanical behavior analysis combining with construction,formulated the "construction principles and the overall design of advance support and strengthen the primary support,reasonable deformation,and then,after the first anti soft rigid support,timely closure,strengthen and improve the geological structure,the bottom forecast",and the tunnel ventilation technology measures and construction machinery optimization and matching technology grow up to carry on the research analysis,has established the construction technology of tunnel with assisted ventilation and mechanical supporting parallel heading,to provide for the safety of the tunnel construction and improve the construction schedule guarantee.