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针对强地震作用下小净距隧道围岩的力学特征,采用三维数值模拟的手段,并引入基于Mohr-Coulomb准则的屈服接近度函数作评价指标,对多种净距条件下隧道围岩地震动力响应特征进行了深入研究。研究结果表明,在强地震作用下,小净距隧道围岩的破坏发展规律是由边仰坡开始,再逐渐由洞口向洞身段发展;小净距隧道中夹岩的应力状态与其净距密切相关,净距越小,距洞口的距离越近,小净距隧道中夹岩屈服接近度值越大;而洞周其余围岩的应力状态仅在间距较小时与隧道间距有关,当隧道间距增大到一定程度后,不再有相关性;最后建议采用以YAI≤0.2的应力状态作为小净距隧道抗震设计的应力标准。
Aimed at the mechanics characteristics of surrounding rock with small clear distance tunnel under strong earthquake, the method of three-dimensional numerical simulation is adopted and the yield proximity function based on Mohr-Coulomb criterion is introduced to evaluate the mechanical characteristics of tunnel surrounding rock under various clearance conditions Response characteristics of the in-depth study. The results show that under the action of strong earthquakes, the damage and development of the surrounding rock of the small clear distance tunnel begin from the side slope and gradually develop from the hole to the body section. The stress state of the rock and the distance between them are close , The smaller the clear distance is and the closer the distance to the hole is, the greater the yield yield value of the rock mass in the small clear distance tunnel is. The stress state of the remaining surrounding rock is related to the tunnel spacing only when the spacing is small. When the tunnel spacing After increasing to a certain extent, there is no longer any correlation. Finally, it is suggested to use the stress state of YAI≤0.2 as the stress criterion for the seismic design of tunnels with small spacing.