Study Of The Influence Factors And Mechanical Mechanism Of Miaohui Tunnel Hard Rock Ground Movement

The strata movement caused by the hard rock tunnel construction is a typical nonlinear mechanical system, which is of great uncertainty and instability, which is likely to cause serious safety accidents.Therefore, it is necessary to analyze the mechanical response of strata movement in order to reduce the probability of accidents.The paper has systematically studied the influencing factors of strata movement and deformation law induced by tunneling ,and the mechanical mechanism of the movement of the strata is revealed, and the research has practical value, which provide scientific basis for the prevention of accidents caused by excessive movement of strata.The main research contents and achievements of this paper are as follows:(1)Based on the orthogonal numerical simulation test, the influence degree of mechanical parameters on the strata movement is analyzed.The main influencing factors of formation subsidence are Ei>Eo>Eb><?o>?i>cb>?o>co>?b ,and the main influencing factors of horizontal movement are Eo>Eb >?i>Ei >cb>?o>?b>co>?i.(2)Based on the bifurcation theory, the calculation formula of the critical height of stratum collapse is established.The calculation results show that the critical height of the blue R1 line of is 14m, and the accuracy of the results is verified by numerical simulation.(3)Analysis of different excavation methods, excavation footage of effects of different stratum movement, the results show that the CRD method was used for engineering construction, the excavation footage is 2m.(4)MIDAS/GTS software is used to simulate the whole process of tunnel construction.Two monitoring sections are selected to analyze the internal law of strata movement, and to discuss the mechanism of the deformation of the strata,and the evolution mechanism of destruction is clarified;The rule of surface settlement and horizontal deformation is further analyzed, and the accuracy of the numerical simulation is verified by field measured data,which pointed out that the accurate selection of mechanical parameters with high influence degree is very important to improve the results of numerical simulation.