On the basis of expert questionnaire and the relevant specification,multi-factors influencing weight matrix was constructed by Analytic Hierarchy Process(AHP)improved in transfer matrix algorithm,and influential fact...On the basis of expert questionnaire and the relevant specification,multi-factors influencing weight matrix was constructed by Analytic Hierarchy Process(AHP)improved in transfer matrix algorithm,and influential factors were fuzzy classified to construct the fuzzy evaluation matrix by using trapezoidal fuzzy membership function.Fuzzy evaluation analysis was carried out through multistage fuzzy comprehensive evaluation method,and verified in combination with engineering construction condition of shallow buried tunnel with large span of Zhongshan Park Station in Qingdao Metro,and four kinds of risk control schemes were established and compared on the analysis of tunnel construction risk.Results show that the model was feasible and the improved construction scheme was very effective to reduce the construction risk.展开更多
To evaluate the strength attenuation law of soft rock in the western mining area of China, we established an evolution model for the strength parameters of soft mudstone at the post-peak stage by employing a tri-linea...To evaluate the strength attenuation law of soft rock in the western mining area of China, we established an evolution model for the strength parameters of soft mudstone at the post-peak stage by employing a tri-linear strain softening model. In the model, a stiffness degradation coefficient co and a softening modulus coefficient a were introduced to take into account the stiff- ness degradation, and the subsequent yield surfaces at post-peak stage were all assumed to meet the Molar-Coulomb yield criterion. Furthermore, attenuation laws of stiffness and strength parameters of soft mudstone were analyzed according to an engineering case. Finally, the model＇s accuracy was verified by comparison of results from numerical calculation and tri-axial compression tests. Results showed that the attenuation of the friction angle was dominated mainly by the instantaneous stress states and damage features, while the attenuation law of cohesion was also related to the plastic behavior. The degradation rates of strength param- eters decreased with increasing confining pressure and the friction angle tended towards its initial value. Residual strengths were also enhanced with increasing confming pressure. The results indicate that the evolution model can accurately describe the strain softening behavior of soft rock.展开更多
基金This Project is supported by the Opening Project Fund of Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation(No.CDPM2013KF05)the National Natural Science Foundation of China(Grant No.51174128)the Specialized Research Fund for the Doctoral Program of Higher Education of China(Grant No.20123718110007).
文摘On the basis of expert questionnaire and the relevant specification,multi-factors influencing weight matrix was constructed by Analytic Hierarchy Process(AHP)improved in transfer matrix algorithm,and influential factors were fuzzy classified to construct the fuzzy evaluation matrix by using trapezoidal fuzzy membership function.Fuzzy evaluation analysis was carried out through multistage fuzzy comprehensive evaluation method,and verified in combination with engineering construction condition of shallow buried tunnel with large span of Zhongshan Park Station in Qingdao Metro,and four kinds of risk control schemes were established and compared on the analysis of tunnel construction risk.Results show that the model was feasible and the improved construction scheme was very effective to reduce the construction risk.
基金Project supported by the National Natural Science Foundation of China （No. 51174128）, and the Specialized Research Fund for the Doctoral Program of Higher Education of China （No. 20123718110007）
文摘To evaluate the strength attenuation law of soft rock in the western mining area of China, we established an evolution model for the strength parameters of soft mudstone at the post-peak stage by employing a tri-linear strain softening model. In the model, a stiffness degradation coefficient co and a softening modulus coefficient a were introduced to take into account the stiff- ness degradation, and the subsequent yield surfaces at post-peak stage were all assumed to meet the Molar-Coulomb yield criterion. Furthermore, attenuation laws of stiffness and strength parameters of soft mudstone were analyzed according to an engineering case. Finally, the model＇s accuracy was verified by comparison of results from numerical calculation and tri-axial compression tests. Results showed that the attenuation of the friction angle was dominated mainly by the instantaneous stress states and damage features, while the attenuation law of cohesion was also related to the plastic behavior. The degradation rates of strength param- eters decreased with increasing confining pressure and the friction angle tended towards its initial value. Residual strengths were also enhanced with increasing confming pressure. The results indicate that the evolution model can accurately describe the strain softening behavior of soft rock.
