Application of the drill-and-blast method generally leads to deterioration of rock properties in a disturbance-damaged region of rock tunnels. In this study

different mechanical models of disturbance-damaged rock tunnels were introduced according to the elastic-plastic states of both disturbance damaged rock and non-disturbance rock. Brittle-plastic solutions of stress

displacement

and plastic zone radius in disturbance-damaged rock tunnels were then presented by adopting the unified strength theory

the elastic-brittle-plastic model

and a non-associated flow rule. Furthermore

the study discussed the conversion paths and determinative approaches of the tunnel mechanical model and compared the results with those in the literature. Influences of various factors were analyzed

demonstrating that the obtained brittle-plastic solution of rock tunnels accounts reasonably for comprehensive effects of intermediate principal stress

tunnel disturbance range

rock post-peak strength

and dilatancy. Additionally

the solutions can be reduced to many traditional ones through combined parameter transformation

and its verification is demonstrated. As a result

it has important theoretical significance and application prospect. The determination of tunnel mechanical model is closely related to intermediate principal stress and rock disturbance range

which significantly affects distributions of tunnel stress and displacement as well as ground reaction curve. Support pressure and tunnel stable deformation increase obviously with the decrease of rock post-peak strength and the increase of dilatancy parameters.