考虑脆性损伤和渗流的圆形水工隧洞稳定性分析

为获得更准确的隧洞围岩塑性范围和力学特征，基于非线性脆性损伤和统一强度理论，考虑渗流场和中间主应力系数，推导出隧洞围岩弹塑性应力和塑性范围表达式。通过算例分析，得出渗透比（围岩与衬砌渗透系数之比）等相关参数对隧洞塑性范围和应力的影响规律。研究结果表明:隧洞切向应力具有不连续性，在衬砌、塑性区交界处及弹塑性交界处均发生突变；随渗透比和围岩脆性程度的增大，围岩塑性半径逐渐增大，塑性区切向应力逐渐减小；中间主应力系数越大，围岩塑性半径越小，塑性区切向应力越大。采用注浆加固圈进行支护，可有效地降低围岩渗透性，减小塑性范围。研究成果可为水工隧洞支护设计和稳定性分析提供一定的理论指导。

Stability analysis on circular hydraulic tunnel considering brittle damage and seepage

In order to obtain the plastic range and mechanical characteristics of surrounding rock in tunnel more accurately, based on the nonlinear brittle damage and unified strength theory, the expressions of the elastic-plastic stress of surrounding rock in tunnel and the plastic range were deduced considering the seepage field and the coefficient of intermediate principal stress. The influence of osmosis ratio (ratio of permeability coefficient of surrounding rock and lining) and other related parameters on the plastic range and stress of the tunnel were concluded through the example analysis. The results showed that the tangential stress of the tunnel has the discontinuity, and it will change suddenly at the junction of the lining and plastic zone and the elastic-plastic junction. With the increase of the osmosis ratio and the brittle degree of surrounding rock, the plastic radius of surrounding rock increases gradually, while the tangential stress in the plastic zone decreases gradually. The greater the coefficient of intermediate principal stress, the smaller the plastic radius of surrounding rock, the greater the tangential stress in the plastic zone. The permeability of surrounding rock and the plastic range will be reduced effectively be using the grouting reinforcement ring for support. The results can provide a certain theoretical guidance for the design and stability analysis of hydraulic tunnel support.