| Large deformation of soft rock is a serious problem in the process of tunnel construction,especially in southwest China.The geological conditions are complex and diverse,and the deformation of soft rock is particularly prominent.Based on the concept of active support,among many support methods,prestressed resin bolt support is one of the effective measures to solve this problem.However,as a commonly used deformation control method in coal mine roadway,prestressed resin bolt has been widely recognized in practice,but its application in mountain railway tunnel is rare and lacks strong theoretical and experimental support.In order to explore the role of prestressed resin bolt in solving the problem of large deformation of soft rock and improve the technical level of the application of prestressed resin bolt in tunnels,this paper mainly relies on the Baishitou tunnel project of Da-Lin railway,and carries out the following research work by means of data investigation,theoretical analysis,field test and numerical simulation :(1)The range of relevant parameters for the adaptability of prestressed resin bolt support capacity is summarized.The influence law of different types of rod bodies on the anchoring performance of resin bolt is clarified;the linear relationship between bond strength of anchorage-rock-soil interface and rock-soil strength is revealed.The control ability of prestressed resin bolt for large deformation of soft rock was clarified by using the Fenner formula;based on the theory of rock mechanics,the calculation method of critical torque of bolt drilling sticking is proposed.(2)By simulating and analyzing the deformation control effect of single prestressed resin bolt on rock mass under confining pressure,the influence law of confining pressure and prestress on surrounding rock deformation is revealed.The influence of different prestressed resin bolt parameters on surrounding rock deformation after tunnel excavation is compared and analyzed,and the influence degree and law of prestressed resin bolt on soft rock deformation control of tunnel are proved.(3)The control improvement degree of soft rock deformation controlled by prestressed resin bolt compared with ordinary mortar bolt and its influence on the internal force of supporting structure are clarified;the excavation method that is conducive to the deformation control of soft rock is proposed.The construction technology of prestressed resin bolt and the factors influencing its supporting effect are summarized.The above research results can provide some reference for the design and application of prestressed resin bolt in similar soft rock tunnel. |
PDF Full Text Request