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在全面考虑了偏压隧道影响因素的基础上,采用FLAC对不同横坡坡度、围岩级别和侧覆土厚下的偏压隧道进行了开挖模拟,通过对隧道开挖变形特征及各关键点位移的分析,指出隧道在侧覆土厚大于20 m后基本不受偏压的影响,在侧覆土厚小于15 m时则需要在开挖前进行预加固措施。基于此,对不同工况下隧道进行的预加固措施的模拟分析,结果表明:V级围岩条件下,侧覆土小于7 m时主要需要解决的是浅埋侧反压能力不够的问题,而大于7 m后需要解决的则是深埋侧压力过大的问题,并在实际工程中得到验证。研究结论可为类似工程的设计和施工提供参考。
Based on the comprehensive consideration of the influencing factors of the biased tunnels, FLAC was used to simulate the biased tunnels with different slope grades, surrounding rock levels and lateral cover thicknesses. Through the excavation deformation characteristics and the key points Displacement analysis shows that the tunnel is basically unbiased when the soil cover thickness is more than 20 m. When the soil thickness is less than 15 m, pre-reinforcement measures are required before excavation. Based on this, the simulation analysis of pre-reinforcement measures for tunnels under different working conditions shows that the main problems to be solved when the side-covering soil is less than 7 m are the insufficient backpressure capability at the shallow buried side under the condition of Grade V surrounding rock The problem that needs to be solved after more than 7 m is the overburden pressure at the deep side, which is verified in practical engineering. The conclusions of the study can provide references for the design and construction of similar projects.