考虑渗流影响的深埋隧道围岩-衬砌相互作用研究

Interaction between Surrounding Rock and Lining of Deep-Buried Tunnel Considering Influence of Seepage

山岭地区深埋隧道经常处于高水压工况,渗流对于隧道围岩及衬砌结构安全有较大影响。基于Mohr-Coulomb准则,推导在渗流力作用下围岩和衬砌结构相互作用的弹塑性解析解,得到围岩塑性区半径、围岩应力、位移以及衬砌径向变形等与支护反力间的解析关系。进一步地,引入围岩收敛曲线(GRC)和支护特性曲线(SCC),分析隧道围岩和衬砌的非线性力学特性,采用收敛约束法求得洞周径向位移。依托牛和岭隧道深埋段工程,验证本文基于Mohr-Coulomb准则的理论解析方法的准确性,并针对富水山区隧道支护反力、塑性半径和洞周径向位移关系进行参数分析。研究结果表明:1)增加支护反力可以有效地限制塑性区的发展和洞周的径向位移,初始阶段限制效果明显,后续增加支护反力的效果逐渐减小;2)围岩塑性半径和洞周径向位移随渗流水压力的增大呈非线性增长;3)塑性区半径不变,低渗透性衬砌可以减小所需的支护反力以及洞周的径向位移。

Deep-buried tunnels in mountainous areas are often under high water pressure condition,in which seepage has a great impact on the surrounding rocks and lining structure safety.Based on the Mohr-Coulomb criterion,the elastoplastic analytical solution for the interaction between surrounding rock and lining structure under the action of seepage force is derived.The analytical expressions of the relations among the radius of the surrounding plastic zone,the stress and displacement of surrounding rock,and the radial deformation of lining with the support resistance are given.Furthermore,the ground reaction curve and support characteristic curve are introduced to analyze the mechanical characteristics of nonlinear interaction between surrounding rock and lining,and the radial displacement around the cave is obtained by the convergence constraint method.Subsequently,relying on the deep-buried section of the Niuheling tunnel,the accuracy of the theoretical analysis method based on the Mohr-Coulomb criterion recommended is verified.Finally,the parameter analysis is performed on the relationship between the support resistance,the plastic radius,and the radial displacement around the cave.The main results show the following.(1)An increase in the support resistance can effectively limit the development of the plastic zone and the radial displacement around the cave.The initial limiting effect is obvious,and the subsequent effect gradually decreases.(2)The plastic radius of the surrounding rock and the radial displacement around the cave show nonlinear growth with the increasing seepage water pressure.(3)In the case of a certain radius of the plastic zone,low permeability lining can reduce the required support reaction force and radial displacement around the cave.The research results can provide a certain theoretical basis for the design and construction of tunnels in water-rich mountain areas.