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为研究中间主应力对硐室围岩稳定性的影响,分别应用统一强度理论和Drucker-Prager屈服准则分析硐室围岩的弹塑性,求解出塑性区和弹性区的应力场、位移场以及塑性区半径的表达式。通过算例,分析不同中间主应力系数对围岩应力分布、塑性区半径和位移的影响。结果表明:统一强度理论求解的塑性区位移和半径随着中间主应力系数的增大而减小;应用Drucker-Prager屈服准则求解的结果,随中间主应力系数的增大表现出先减小后增大的趋势,在中间主应力系数等于0.8的位置出现拐点,用统一强度理论求得的极限强度比用Drucker-Prager屈服准则求得的大。因此,在硐室围岩的求解过程中不能忽略中间主应力对围岩的作用。
In order to study the influence of intermediate principal stress on the stability of surrounding rock, the elasto-plastic properties of the surrounding rock of the chamber were analyzed by unified strength theory and Drucker-Prager yield criterion respectively. The stress field, displacement field and plasticity of the plastic zone and elastic zone Area radius expression. Through an example, the influence of different intermediate principal stress coefficients on the stress distribution, plastic zone radius and displacement of surrounding rock is analyzed. The results show that the displacements and the radius of the plastic zone reduced by the unified strength theory decrease with the increase of the intermediate principal stress coefficient. Using the Drucker-Prager yield criterion, the results show that the plasticity zone first decreases and then increases with the increase of the intermediate principal stress coefficient Large inflection point appears at the position where the principal stress coefficient is equal to 0.8, and the ultimate strength obtained by the unified strength theory is larger than that obtained by the Drucker-Prager yield criterion. Therefore, the effect of the middle principal stress on the surrounding rock can not be neglected in the process of solving the surrounding rock in the chamber.