A time-dependent swelling constitutive model for reliability analysis of anhydrite tunnel

The anhydrite rock is easy to swell and soften after encountering water, which leads to an increase in the displacement of the tunnel face and the force of the supporting structure, resulting in disasters such as tunnel lining invasion, destruction and floor uplift. Thus the physical model tests of the swelling evolution process of anhydrite rock are carried out, based on which, a time-dependent swelling constitutive model of anhydrite and two performance functions of tunnel are established. At the same time, a calculation framework is proposed for the reliability analysis of tunnel subjected anhydrite swelling, whose reliability influencing parameters is investigated. The comparisons of reliability of tunnel are conducted under the conditions of soaking and no soaking. The sensitivity analysis of reliability indices is performed by using the Latin hypercube sampling (LHS) technique and calculating the partial rank correlation coefficients. The reliability-based design of tunnel with anhydrite swelling is illustrated and the influence of groundwater distribution on the reliability is discussed. The research results provide a theoretical basis for tunnel stability and reliability analysis.