Supporting Mechanism And Computational Analysis Of Large-buried Tunnel Crossing Fault Fracture Zone

In recent years,the state has paid more and more attention to the development and utilization of resources,and has carried out a large number of related projects,such as the Yangtze River and Huaihe River Project,the Dianzhong Water Diversion Project,and the Xijiang Datengxia Water Control Project,all of which have high geostress,high depth,and high press of water.The characteristics of water pressure and so on are extremely difficult to construct.It is urgent to carry out relevant experimental research to ensure the smooth progress of the project.This study is based on the large-scale national project "Dianzhong Water Diversion Project",which diverts the relatively abundant water from the Jinsha River to arid Dian.In the middle area,to alleviate the contradiction of local water use,the main study of the Xianglushan tunnel is the key control project of the water diversion project in the central Yunnan,and the main problem of this project is the support design when the diversion tunnel passes through the fault rupture zone.Optimization problems,although many studies on fault rupture zones have been studied at home and abroad,they still cannot be fully applied to the engineering background of "drainage in the middle of the river".It is still insufficient for the study of the excavation and anchorage of the large buried tunnel through the fault rupture zone.Perfect,and no quantitative analysis of support.Therefore,the research results obtained in this paper with the pilot water diversion as the engineering background are as follows:A.By anchoring rock-like specimens with weak interlayers and carrying out uniaxial compression tests,it is found that the support effects of the weak interlayer specimens with different dip angles are different,and anchoring the weak interlayers of 30° and 60° dip angles When the sandwich test piece is integrated,the support effect is the best;the optimal anchorage angle of the sandwich test piece plus anchor is found to be between 0° and 30°from the normal of the sandwich layer,and the optimal anchor length is 6cm and diameter.It is 2.8mm;and when the optimal support range is reached,the test piece will have a very regular "cracking" phenomenon,which can be used as the optimal method for anchoring.Finally,the experimental results are analyzed and found to be under different dip angles.An empirical formula for the equivalent peak intensity of different bolt inclinations.B.Through the physical and mechanical model test of the typical cave section,it is found that the area where the surrounding rock stress of the tunnel excavation is significantly affected by the excavation disturbance is within the range of 1 hole diameter,and the stress of the surrounding rock is more than 1 times.The maximum deformation of the hard rock under the support is about 10mm,the maximum displacement of the soft and hard alternating parts is about 35mm,and the maximum deformation of the soft rock section is about 60mm,and the joint support of the lining bolts reduces the average deformation of each hole by 11%,21%and 11%;the radial and tangential stresses of the surrounding rock and soft rock sections of soft and hard rock are particularly obvious,that is,in the soft surrounding rock section,the role of the anchor is fully exerted,and the anchor reinforcement and The support effect is more significant.C.Through the Flac3D numerical simulation of the tunnel excavation,the basic law of large variation of stress and strain in the model hole diameter is verified.It is found that the segment support reduces the maximum displacement by 8%,and the bolt support After reaching 6%,14%after joint support,to achieve the best results.It is also found that the stress of the tunnel crossing the fault part is greatly alleviated after the lining support,and the support of the bolt makes the stress concentration around the tunnel relieved,but the stress concentration at the boundary of the face still exists.D.Through the numerical simulation analysis of tunnels considering different buried depths,fault dip angles,fault thickness,bolt length,bolt spacing and lining thickness,the empirical formulas of support effects under multiple factors are obtained and found.The influence of fault dip is the most obvious,followed by lining thickness,anchor spacing,bolt length and buried depth,while the influence of fault thickness is the smallest,which provides a reference for common engineering problems.In this paper,the anchoring mechanism of fault rupture zone is studied,and the optimal optimization method is analyzed and the empirical formula of anchoring reinforcement is obtained.A series of model tests are carried out to simulate the real situation of site excavation with the water diversion in the middle of the project,and the anchorage is analyzed in the fault.The optimal anchorage length and inclination angle of the rupture zone are used to guide the engineering practice;a series of numerical calculations are not only applied to a single place,but also a general optimization support method can be obtained.