关键词: 隧道洞口边坡, 强震区, 离心振动台试验, 动力响应

Abstract: The investigation of tunnel damage after strong earthquake shows that the seismic damage of tunnel entrance is quite serious, so it is necessary to further investigate the dynamic response of tunnel entrance slope. Taking the typical tunnel entrance slope in Wenchuan earthquake area as an example, the dynamic response characteristics of tunnel entrance slope under strong earthquake are studied using large centrifugal shaking table test. The experimental results show that: 1) The acceleration amplification on the slope and inside the slope has a significant elevation effect, the acceleration amplification coefficient of the tunnel arch roof is larger than that of the other parts of the tunnel, and the closer to the tunnel entrance the more obvious the acceleration amplification effect. 2) The acceleration amplification effect of the slope is very obvious for different amplitudes, and the acceleration response at low amplitude is larger than that at high amplitude. 3) Under the condition of maintaining 0.25g excitation, the acceleration amplification coefficient of slope under different centrifugal load grades is greater than 2.0, but the acceleration magnification factor is basically flat with the increase of centrifugal load. 4) With increasing slope elevation, the dynamic earth pressure decreases linearly, and the dynamic earth pressure response coefficient at the relative elevation of 0.48 (i.e., tunnel arch roof) is the largest. Research results can provide reference for the design and research of seismic mitigation for tunnel entrance in strong earthquake area.

Key words: tunnel entrance slope, strong earthquake area, centrifugal shaking table test, dynamic response