A closed-form hydraulic-mechanical coupling solution of a circular tunnel in elastic-brittle-plastic rock mass

Considering the changes of permeability and Biot's coefficients, the closed-form elastic-brittle-plastic solution of lined circular tunnels was proposed employing a Mohr-Coulomb non-associated flow rule. The influence of the reserved deformation of lining structure, permeability and Biot's coefficients on the plastic radius, displacement and water inflow was studied. With an increase in permeability of the plastic region, the plastic radius and displacement decrease, and the water inflow increases. With an increase in Biot's coefficient, the plastic radius, displacement and water inflow approximately increase in a linear way. The pore-water pressure in the surrounding rock increases with decreasing permeability of lining structure, and the water inflow has a contrary evolution. The increasing reversed displacement of lining structure increases the plastic radius, and lining structure reduces the water inflow but increases the pore-water pressure of the surrounding rock.

Automated summary

The closed-form elastic-brittle-plastic solution of lined circular tunnels proposed using a Mohr-Coulomb non-associated flow rule considers the changes in permeability and Biot's coefficients. The study finds that an increase in permeability decreases plastic radius and displacement while increasing water inflow, whereas an increase in Biot's coefficient leads to a linear increase in plastic radius, displacement, and water inflow. The pore-water pressure in the surrounding rock increases with decreasing permeability of the lining structure, impacting water inflow in a contrary manner, and an increasing reversed displacement of the lining structure affects plastic radius and water inflow.