Zhou Y.,Central South University |
Zhou Y.,University of Science and Arts of Iran |
Liu J.-X.,Central South University |
Fang J.-Q.,Guangdong Yunwu Highway Expressway Ltd. |
Liu Q.-Y.,Central South University
Yantu Lixue/Rock and Soil Mechanics | Year: 2012
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.
Lin H.,Central South University |
Cao P.,Central South University |
Fang J.,Guangdong Yunwu Highway Expressway Ltd. |
Liu Q.,Central South University
Disaster Advances | Year: 2012
The timbering time of the tunnel is an important content of tunnel design and the accurate confirmation of reasonable timbering time of the second liner plays an important role in giving play to the fully self-supporting capacity of surrounding rock. However, the rheological property of rock mass has seldom been considered in previous researches concerning the timbering time of the second liner of tunnels. As there is a time process in the instability or damage of rock mass engineering, which is influenced by the rheological property of rock and as the timbering time of second liner of tunnels is concerned with the problem of timeliness of rock mass deformation, so the influence from rheological properties of surrounding rock should be more often considered. Therefore, in order to study the timbering time of the second liner of tunnels in the rheological property cases of rock mass, this paper first deduces the expressions for the resistance, displacement of lining and displacement of surrounding rock. Then, it takes the rock mass of the tunnel section in Gaoyao(Guangdong Province)-Wuzhou Expressway as the engineering background to discuss the method of confirming the timbering time of the second liner of tunnels in rheological cases of rock mass and to compare the measured value and theoretical calculation value on sinking vaults of surrounding rock. The analysis results indicate that the time- distance curve of the predicted sinking vault presents the same developmental law as the actual field measurement when considering the rheological effect and that their timbering time is the same basically, thus verifying the correctness of the method.