The Niucheding tunnel in Guangzhou-Wuzhou Expressway is taken as the engineering background

the analytical and numerical calculation method for the second lining time of tunnel under the conditions of rock mass rheological characteristic are analyzed. The disciplines of the arch settlement obtained from the proposed method are compared with that from the monitoring data; then the numerical calculation model is founded to analyze the influence of stress releasing coefficient on the stability of surrounding rock mass of tunnel. The analysis results show that

the disciplines of the arch settlement obtained from the proposed method are the same with that from the monitoring data

which validates the correctness of the proposed method. The stress of surrounding rock mass is released gradually with the tunnel face moves on; and the releasing rate is slow in the III degree of rock mass

which shows obvious spatial effect. According to the numerical calculation results

if the stress releasing coefficient is larger or equal to 60%

the whole area of the disturbed zone is larger than the area the bolt can reinforce. Finally

the appropriate second lining time is obtained so as to give some guidance for the real practice.