Abstract: This paper describes the mechanical mechanism of rock bolts acting on the elastic-plastic stratum around tunnel. The design approaches of rock bolts and shotcrete linig are investigated. Meanwhile, the formula, of the stress and displacement, based on the effect of a foundation pile in the swelled ground, has been proposed. The relationship among the length, diameter and distance of the rock bolts and some parameters of geologic media can be obtained by the above formula. Two examples are given to illustrate the practical application under the soil and weak rock condition.