水平地应力对软弱围岩隧道力学性能影响分析

Analysis of the Impact of Horizontal In-situ Stress on Mechanical Properties of Weak Surrounding Rock Tunnel

为研究水平地应力对软弱围岩隧道围岩稳定性问题,采用FLAC3D数值模拟软件,基于Mohr-Coulomb屈服准则,对未采取加固手段的Ⅳ级围岩隧道受不同水平地应力影响下围岩的水平位移、垂直位移和最大主应力进行计算分析,得出以下结论:1)垂直地应力不变,随着水平应力的增加,围岩的最大水平位移与最大垂直位移逐渐增加.2)当λ<1时,水平地应力变化对围岩水平位移影响较大;当λ>1时,水平地应力变化对围岩垂直位移影响较大.3)当地应力出现偏压状况时,最大主应力为局部分布状态;当垂直地应力与水平地应力相等时,围岩主应力分布均匀.

In order to study the horizontal rock stress on the surrounding rock stability of weak surrounding rock tunnels,this paper uses FLAC3D numerical simulation software and Mohr-Coulomb yield criterion.The horizontal displacement,vertical displacement and maximum principal stress of the surrounding rock under the influence of different levels of in-situ stress in the unreinforcedⅣ-level rock tunnel are calculated and analyzed.And conclusions are drawn as follows:1)When the vertical ground stress remains unchanged,the maximum horizontal displacement and maximum vertical displacement of surrounding rock gradually increase with the increasing of the horizontal stress.2)Whenλ<1,the horizontal stress change has a greater impact on the horizontal displacement of surrounding rock;whenλ>1,the horizontal stress change has a greater impact on the vertical displacement of surrounding rock.3)When the local stress appears biased,the maximum principal stress is locally distributed;while the vertical in-situ stress is equal to the horizontal in-situ stress,the main stress in the surrounding rock is evenly distributed.