双向不等压圆形巷道围岩塑性区理论分析及数值模拟

    Theoretical Analysis and Numerical Simulation on Plastic Zone in Circular Tunnel Under Bidirectional Non-uniform Stress Field

    • 摘要: 根据弹性力学中圆孔应力解的方法,利用莫尔-库仑强度准则,推导出了双向不等压应力场载荷作用下圆形巷道围岩塑性区的边界方程。从理论分析和数值模拟对比分析的角度出发,分析了侧压系数、围岩岩性、开挖半径对圆形巷道围岩塑性区的影响。结论表明:双向不等压载荷作用下,圆形巷道围岩较大载荷方向的塑性区尺寸小于较小载荷方向的塑性区尺寸;巷道围岩越坚硬塑性区分布范围越小,围岩为软弱岩层时塑性区呈蝶形分布,围岩为坚硬岩层时,塑性区呈椭圆形分布;巷道开挖半径对巷道围岩塑性区分布范围影响较大,同一角度处的塑性区半径随着巷道半径的增加呈线性增加。

       

      Abstract: According to the stress of a circular hole in elastic-plastic mechanics and using Mohr-Coulomb strength criterion, we deduced the boundary equations of circular roadway plastic zone in uneven stress field. From the perspective of theoretical analysis and numerical simulation, and compared and analyzed the effect on the distribution of the circular roadway plastic zone under the factor of lateral pressure coefficient, rock lithology and tunnel radius. The results show that under the non-uniform stress field, the lateral pressure coefficient has more influence on the shape and distribution of plastic zone, the plastic zone size of the larger load direction is smaller than that of the smaller load direction; the harder of the roadway rock, the smaller of the range of plastic zone; when the surrounding rock is weak rock, the plastic zone is approximate butterfly distribution, and when the surrounding rock is harder rock, the plastic zone distribution is approximate elliptic. The influence of roadway excavation on the distribution range of the plastic zone of surrounding rock is larger; at the same angle, the radius of plastic zone is linear increase with the increase of tunnel radius.

       

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