不同施工顺序对陡坡偏压小净距隧道围岩稳定性的影响研究

为了研究陡坡偏压条件下不同施工顺序对小净距隧道围岩稳定性的影响，结合工程实例，考虑“先浅后深”与“先深后浅”两种施工顺序，通过有限元软件ABAQUS建立三维弹塑性分析模型进行了施工全过程数值模拟，重点分析了不同施工顺序对地表边坡、拱圈特征点围岩以及中夹岩柱的影响，并计算了不同施工顺序下的隧道开挖安全系数。结果表明:先施工深埋侧隧道会加剧围岩整体偏压效应，并会对中夹岩柱处围岩产生往返的扰动，不利于围岩稳定性的控制，且先开挖浅埋侧隧道的安全性高于先开挖深埋侧隧道。

Study on influence to stability of surrounding rock by different construction sequence for bias tunnel with small interval and steep slope

In order to study the influence of different construction sequence on the stability of surrounding rock for bias tunnel with small interval and steep slope, combined with engineering example, a model of 3D elasto plastic analysis was established through the finite element software ABAQUS considering two construction sequences of "shallow to deep" and "deep to shallow". The numerical simulation was conducted on the whole process of construction, and the influence of different construction sequence on surface slope, surrounding rock of arch characteristic points and middle rock pillar was analyzed emphatically, then the safety coefficients of tunnel excavation under different construction sequences were calculated. The results showed that the construction of deep buried side tunnel at first will intensify the whole bias effect of surrounding rock, and generate the back and forth disturbance to surrounding rock of middle rock pillar, which is not conducive to the control on stability of surrounding rock. The safety of excavation on shallow buried side tunnel at first is higher than that of excavation on deep buried side tunnel at first.