关键词: 非一致性, 长大隧洞, 随机地震动, 时空效应, 相关性

Abstract: To study the time-space effect of the dynamic response of a long tunnel under non-uniform ground motions, firstly, a random ground motion synthesis method was used to generate different ground motion time histories, which can reflect local site effects such as traveling wave effects and attenuation effects of long-distance tunnels. Through vertical input, the dynamic responses of the surrounding rock and liner of the long tunnel under the action of uniform and non-uniform ground motions were analyzed. On this basis, through the Fourier spectrum, transfer function and coherence function, the spectral correlation between the input earthquake and the dynamic response of the surrounding rock was revealed. Secondly, the spatial inconsistency of the dynamic response of surrounding rock in different parts was studied in terms of acceleration, displacement, and relative displacement time history. Finally, the coordination of seismic dynamic response of surrounding rock and liner was studied by analyzing their dynamic characteristics under the action of ground motion. The results show that the transmission coefficient of the surrounding rock monitoring points at the same position in the axial direction of the tunnel is inconsistent in the main frequency band under non-uniform ground motion. During the upward propagation of ground motions, the maximum coherence coefficient between the response of each monitoring point along the elevation and the input ground motion has a basically quadratic polynomial correlation with the elevation, but the maximum coherence coefficient of the non-uniform ground motion input is significantly greater than that of the uniform ground motion input. Under non-uniform ground motion input, although there is a certain delay in the displacement time history of the surrounding rock monitoring point at the same location along the tunnel axial direction, the maximum displacement of the surrounding rock at the exit of the tunnel occurs earlier than that at the entrance of the tunnel. Also, the peak acceleration and displacement of the surrounding rock monitoring points near the tunnel and the maximum relative displacement of the top and bottom monitoring points show the same distribution trend that all of them are larger at both ends and smaller at the middle along the tunnel axis. Due to the traveling wave effect, the shear action will be generated at the left and right ends of the tunnel under non-uniform ground motion input. This study can provide a comprehensive understanding of the destruction mechanism of long tunnels under the action of earthquakes.

Key words: non-uniform, long tunnel, random ground motion, time-space effect, correlation