| With the rapid development of China’s economy,the volume of road transportation is increasing,and a large number of mountain tunnels have been built.China is located in the world between the two major active seismic zones,high intensity seismic areas are widely distributed,frequent earthquake disasters.Due to the limitation of hydrogeology,survey precision,construction level and maintenance technology,tunnel stratum cavitation and other hidden diseases appear in large numbers,which seriously reduces the integrity of surrounding rock.Under the action of earthquake,cavitation and tunnel lining structure produce dynamic interaction,threatening the stability and safety of tunnel structure.In this paper,theoretical analysis,finite element calculation and orthogonal test are used to study the influence of stratum cavity on seismic dynamic response of tunnel.The main research contents and conclusions are as follows:(1)The free field boundary is used to simulate the propagation of ground motion in infinite space,and the representative seismic wave of Kobe is selected.The noise filtering and baseline correction are carried out,and the seismic wave energy range and calculation cost are considered to be properly truned.(2)Based on the theory of wave,the wave function expansion method and Fourier-Bessel series transformation,including void formation in the incident plane SV wave are tunnel displacement analytical solution of dynamic response,and compared with numerical solution,numerical simulation and analytical solution of displacement amplitude peak displacement amplitude peak differ by about 9%,show that the analytical solution as fast dynamic response displacement of tunnel method has good practicability.(3)Taking a mountain tunnel as the engineering background,using orthogonal test method and considering five influencing factors,a three-dimensional finite element model was established.By sorting out the calculated data through range analysis and variance analysis,the failure mechanism and change rule under the interaction between void and tunnel were determined:Seismic wave incident Angle and buried deeply significant influencing factors of the cavity and the local displacement of the tunnel and the effective stress control effect,and other factors affecting the seismic dynamic response of the tunnel effect,the nearer the hole distance tunnel,the risk of tunnel is not a linear increase,hollow and tunnel center distance is 1.25 times the diameter of the tunnel or 0.15 times the diameter of the hole radius of tunnel,the existence of the empty can have the effect of reduction to elimination of the tunnel.This study can provide reference for seismic design of underground engineering. |
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