Study on the Classification and Evaluation Method of the Frost Susceptibility of Rock Mass

摘要

Engineering designs in cold regions should consider the influence of the frost heave of the ground. In such regions, the classification and evaluation of the frost susceptibility of rock mass is significant in the design of constructions. A calculation method for the frost heave ratio of rock is obtained by fitting the experiment data. The typical dilation of a saturated fracture is discussed, and the linear frost heave ratio of the fracture is provided. The frost heave ratios of different grades of rock masses are computed by simplifying the rock fracture morphology as "layered". The frost susceptibility of rock mass is classified into non-frost susceptible, weakly susceptible, moderately susceptible, strongly susceptible, and very strongly susceptible according to frost heave ratio, based on the frost heaving classification of the soil. Rock masses are non-frost susceptible to weakly susceptible in deformation-based construction designs. In force-based designed constructions such as tunnels and caverns, grades Ⅰ-Ⅲ rock masses are non-frost susceptible to weakly susceptible, whereas grades Ⅳ-Ⅴ rock masses are non-frost susceptible to very strongly susceptible. The frost susceptibility of rock mass can be evaluated according to the porosity of the rock, the grade of the rock mass, and the frost heave susceptibility of rock and fissure filler. The frost susceptibility of the surrounding rock in two cold-region tunnels are assessed, and the results provide references for anti-frost damage design of the tunnel.