AN APPLICATION OF ANALYTICAL METHOD FOR EVALUATING THE STRESS-STRAIN STATE OF DEEP LINED CIRCULAR TUNNELS IN DRY ANISOTROPIC ROCK CONSIDERING ROCK-LINING INTERACTION AND CONSTRUCTION STAGES

Abstract

In the context of Vietnam's strategic orientation toward developing nuclear energy, the disposal of high-level radioactive waste (HLW) from nuclear power plants is a pressing issue that must be addressed. The long-term storage of HLW in deep geological repositories is a solution being researched and applied in many developed countries, wherein deep tunnels constitute a fundamental component of this system. Circular cross-section tunnels at depth are also widely used for road and high-speed railway tunnels through mountains. Currently, studies on deep tunnels, where the rock strata often exhibit anisotropic properties, are rarely mentioned and investigated in Vietnam. This article aims to present an analytical method for evaluating the stress-strain state of a deep, lined circular tunnel in a dry, anisotropic rock mass, considering the rock-liner interaction under two conditions: perfect bonding and relative slip. Additionally, the influence of the tunnel face advance on the stress-strain state of the tunnel is taken into account based on the well-known convergence-confinement method. The analytical solution for the interaction problem is developed using the complex potential approach with the conformal mapping technique and the theory of thin elastic cylindrical shells. The derived analytical solution is verified against available solutions for several special cases. Based on the obtained solution, parametric studies of the anisotropic rock mass are conducted to assess their influence on the liner's response. This analytical solution can serve as a rapid analysis tool for the preliminary design of deep tunnels in anisotropic rock.