Analysis Of Strengthening And Reinforcing Effect Of High-speed Railway Foundation Crossing Active Fault Zone

China is located in the two major seismic belts of the Pacific Rim and the Himalayas-Alps,with complex geological structures and numerous active faults.The number of high-speed railways crossing active fault zones is also increasing,and it is particularly important to ensure the stability of high-speed railway subgrades crossing active fault zones.Therefore,it is imperative to strengthen the foundation and foundation of the high-speed railway crossing the active fault zone,and it is of great significance to study its strengthening effect and optimization design.This paper takes the Xuyan high-speed railway project spanning the Tan-Lu fault zone as the research object.On the basis of on-site investigation,test,engineering design and calculation analysis,the active forms of different active fault types and the subgrade forms treated with different strengthening and reinforcement measures are carried out.By dividing and distinguishing different fault activity modes,a high-speed railway foundation analysis model with different reinforcement treatment measures under the action of active faults was established,and the reinforcement of subgrade stability by different reinforcement treatment measures under the conditions of different fault activity modes,activity reinforcement,etc.was studied.An optimized design is proposed.The main results achieved are as follows:(1)Numerical analysis models of different types of active faults under different conditions of foundation strengthening and reinforcement measures are established.It provides the basis for different pile spacing,pile diameter,pile length of piled foundation,and different reinforcement length,reinforcement spacing and elastic modulus model division of reinforcement roadbed.(2)The optimal foundation treatment measures and their strengthening and reinforcement effects on the foundation under different active fault activity modes are clarified.Through the establishment of the finite element model of the subgrade under the reinforcement treatment of the piled foundation,the influence of different pile spacing,pile diameter and pile length on the deformation of the subgrade under the action of various fault activity modes is analyzed.(3)Discuss the best technical parameters of subgrade reinforcement and its reinforcement effect on subgrade under different active fault activity modes.Through the establishment of the finite element model of the subgrade under the joint reinforcement of the reinforced roadbed and the piled foundation,the effects of different lengths of reinforcement,spacing of reinforcement and elastic modulus of reinforcement on various fault activities under certain pile parameters are analyzed.The influence of the deformation of the subgrade under the action of the method provides reliable technical parameters for the design of the reinforcement and reinforcement of the subgrade across the active fault zone.