Optimization Study On The Underground Structure Anti-seismic Calculation With Response Acceleration Method

In China the construction of underground structure is now growing rapidly fast, with its status becoming more and more important in current social and economic development. As different degrees of seismic demage to the underground structures happended in previous earthquakes at home and abroad, anti-seismic of underground structures has been increasingly attracting emphasis. Researchers in domestic or overseas have been making a study of its anti-seismic issue, achieved some progress and proposed some relevant aseismic calculation method. At present, the quietude analysis method and dynamic time-history analysis method are common ways on the underground structure seismic calculation. The quietude analysis methods, particularly response displacement method and the response acceleration method, are easier on compute and faster on realization than the dynamic time-history analysis method, which easily get promotion and application in engineering design. However, the quietude analysis methods have some problems, such as calculation principle and parameters values, the reliability of its results is limited. Therefore, this article does the optimization research on the response acceleration method. The main contents and achievement are below:â‘ The thesis makes a brief of the reaction mechanism in the anti-seismic of underground structures, then analyzes and compares some seismic design methods on calculation principle and existing problems, which are seismic coefficient method, response displacement method, response acceleration method and dynamic time-history analysis method.â‘¡The optimized improvement has been done aiming at the response acceleration method not behaving the soil dynamic parameters and damp effect.1)Considering the soil mass characteristic under earthquake is different from which is under the static state, the equivalent elastic modulus is taken as the parameters in 2-D finite element of soil by doing 1-D soil layer seismic response analysis in PROSHAKE.2)Considering the damping effect on the seismic wave energy in the process of dynamic response, shear difference between soil layers from 1-D analysis is taken as the equivalent horizontal seismic load to 2-D finite element of soil.3)Through setting the move acceleration of components, the equivalent horizontal seismic load can be loaded rapidly in ANSYS. The optimization on the response acceleration method have been suggested by some means above-mentioned.â‘¢On the example of the anti-seismic calculated analysis for the rectangular section tunnel in multilayer soils, the response displacement method, the response acceleration method and the optimized method have been used in the quietude analysis, while the dynamic time-history analysis method has been used in the dynamic analysis. Comparing the results of quietude methods with those of the dynamic time-history analysis method, the reliability of results on the optimized method has been verified in the thesis.