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Changjiang, China

Ma S.,North China University of Water Conservancy and Electric Power | Cao L.-H.,North China University of Water Conservancy and Electric Power | Xiao M.,Wuhan University | Zhang Z.-G.,Changjiang Design Institute
Sichuan Daxue Xuebao (Gongcheng Kexue Ban)/Journal of Sichuan University (Engineering Science Edition) | Year: 2012

The issues of choosing proper intercepted range of dynamic analysis model and its artificial boundary setting were discussed. Based on the distribution characteristics of seismic wave field of underground caverns, the setting method for artificial boundary used in time history analysis of underground caverns was presented, which allowed the free surface not to be covered by analysis model. The wave field reflected by free surface was calculated using analytical method and then incident into analysis model through artificial boundary. Based on wave field separation principle, artificial boundary surrounding the analysis model could well absorb outgoing scattered wave to guarantee the accuracy of computation. The theoretical test and practical case calculation indicated that the presented method is sufficiently accurate and able to meet the requirements of time history analysis of underground caverns. Meanwhile, the amount of computation can be considerably reduced and the time-consuming is lowered accordingly.

Yang Y.,Wuhan University | Yang Y.,Changjiang Design Institute | Chen J.T.,Wuhan University | Xiao M.,Wuhan University
Materials Research Innovations | Year: 2015

Aiming at the issue of seismic strengthening of underground caverns, a strain rate-dependent plastic constitutive model is established. In addition, dynamic algorithms of bolt and lining are presented. Using the proposed model and algorithms, the influences of parameter variations of bolt and lining on seismic strengthening of underground caverns have been calculated. The results show that bolt and lining can effectively improve the seismic stability of underground caverns. Furthermore, supporting effects of bolt are superior to lining. The optimum support parameters of both bolt and lining support are existed. Below the optimum support parameters, with the improvement of parameters, the supporting effect is significantly enhanced. Above the optimum support parameters, the supporting effect will be slightly enhanced. The optimum support parameters vary at different positions of the caverns. The research provides a theoretical basis for seismic design of caverns.

Zhang Z.-G.,Changjiang Design Institute | Zhang Z.-G.,Wuhan University | Yang Y.,Wuhan University | Mou C.-L.,Changjiang Design Institute | Xiao M.,Wuhan University
Yantu Lixue/Rock and Soil Mechanics | Year: 2014

According to numerous in-situ investigations of earthquake disasters, it is widely regarded that underground structure is of key significance for seismic design of underground cavern. Since no specified simulation methods are definitely issued in the specifications for seismic design of hydraulic structures in China, three common seismic calculation methods of underground structure including quasi-static analysis method, response spectrum method and time-history method are discussed. Numerical calculation are conducted using these methods for underground powerhouse structures of Yingxiuwan hydropower station under Wenchuan earthquake; and calculation results are analyzed based on the in-situ investigation of earthquake disasters. The results show that three methods can reflect the dynamic failure of underground structures to some extent and provide a theoretical basis for the seismic design. It is also shown that the calculation results of the quasi-static analysis method is prior to more safer design and unreasonable for simulating top arch and corbel; response spectrum method can estimate weak parts of structure, but not exactly in interaction analysis of concrete structure and surrounding rock; time-history method is able to precisely simulate the seismic response process under the earthquake disaster; and calculation result is best consistent with in-situ investigation of earthquake disasters, which is better for precise and economic engineering design. Time-history method is suggested to be used for dynamic calculation for the underground powerhouse of high level security, large-scale or in high seismic intensity region.

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