注浆、衬砌作用下非线性渗流隧洞弹塑性解

为探求深埋隧洞在非线性渗流条件下围岩-注浆圈-衬砌体系的力学行为,引入Izbash非线性渗流模型,给出了围岩-注浆圈-衬砌体系的水头分布,基于统一强度理论,考虑塑性区可能的分布位置,在注浆、衬砌支护作用下对隧洞位移、应力和塑性区半径进行了理论推导.通过算例将理论解与数值解对比分析,验证了研究方法的可靠性,并进一步探讨了考虑非线性渗流对富水山岭隧洞支护设计的工程意义.研究结果表明:非线性渗流对隧洞弹塑性力学的影响主要体现在围岩水力梯度系数m_1;围岩从低速非线性渗流向高速非线性渗流转变过程中,塑性区半径和位移越来越大,围岩应力有所减小;应从隧洞围岩的非线性渗流角度考虑注浆圈、衬砌支护厚度设计.研究成果为非线性渗流隧洞支护设计提供了理论依据.

Elastoplastic solution of tunnel with non-linear seepage under grouting and lining support

To explore the mechanical behaviors of surrounding rock-grouting ring-lining system in deep tunnel under non-linear seepage condition, Izbash non-linear seepage model was introduced and the hydraulic head distribution of surrounding rock-grouting ring-lining system was given. Based on the unified strength theory and considering the possible location of plastic zone, the displacement, stress, and radius of surrounding rock plastic zone under grouting and lining support were deduced theoretically. Theoretical results and numerical solutions were compared through an example and feasibility of the theoretical method was verified. The engineering significance for the supporting design of mountain tunnel with rich water considering non-linear seepage was further discussed. Results show that the influence of non-linear seepage on elastoplastic mechanical effect of tunnel was mainly reflected in the hydraulic gradient coefficient m₁ of surrounding rock. In the process of the transition from low-speed non-linear seepage to high-speed non-linear seepage, the radius and displacement of plastic zone became larger, and the stress of surrounding rock decreased. The thickness design of grouting ring and lining support should be considered from the perspective of non-linear seepage of surrounding rock. The research results provide a theoretical basis for the support design of non-linear seepage tunnel.