Research On Practical Seismic Analysis Methods And Performance Index Of Underground Structures

A systematic study on practical seismic analysis methods and performance indexof underground structures is carried out in the dissertation through theoretical analysisand numerical simulation. A comprehensive comparison of practical methods forseismic analysis of underground structures is conducted. Furthermore, the dissertationdelves into the widely used response deformation method and proposes two types ofintegral response deformation method. In addition, the failure mode of undergroundstructures is verified and qualified performance indexes of rectangle undergroundstructures are presented. The dynamic analysis model of tunnel under asynchronousseismic waves is established, and a practical method of longitudinal seismic analysis oftunnel is proposed. The main achievements of this dissertation are described in asfollows:(1) A systematic comparative study on practical seismic analysis methods ofunderground structure is conducted. The common simplified methods for the seismicanalysis of underground structures are introduced, such as seismic coefficient method,free-field racking deformation method, soil-structure interaction coefficient method,response deformation method, response acceleration method and Pushover analysismethod. Sources of error in these methods are analyzed according to the assumptionsadopted by these simplified calculation methods. Based on the numerical results ofDaikai subway station, comprehensive comparison of the methods is carried out. Thecontributions can provide a reference for engineering practice.(2) Two types of integral response deformation method are proposed. Based on thesubstructure method and the integral finite element method for soil-structure dynamicinteraction, the basic principle of the classical response deformation method is verified.In consideration of the disadvantages of classical response deformation method incalculation accuracy, computational cost and range of application, some improvementsof the method are made. This dissertation comes up with two types of integral responsedeformation method by changing the calculation model and the seismic load. Theimproved methods are compared with the dynamic analysis method by numerical simulation. The results show that the integral response deformation methods achievemore accurate result, require less computational complexity and have a more wide rangeof application.(3) This dissertation looks at performance indexes of underground reinforcedconcrete frame structures. The failure mechanism of underground reinforced concreteframe structures is studied through the Pushover analysis of typical subway stationstructures. Based on the failure mode of underground structures, the performance levelsof subway underground structures are proposed. By parameter analysis of typicalsubway stations and data statistics study of seismic experiments, qualified performanceindexes of underground reinforced concrete frame structures are put forward.(4) The integral response deformation method for longitudinal seismic analysis oftunnel is presented. Employing1D time-domain finite element method, the calculationmethod of free-field motion under oblique SH wave is introduced. A FORTRANprogram is compiled to simulate the oblique SH wave input. The dynamic analysismodel of tunnel under asynchronous seismic waves is established, and the influence ofoblique wave to longitudinal seismic response of tunnel is studied. Utilizing thecalculation method of free-field motion under oblique SH wave, the integral responsedeformation method for longitudinal seismic analysis of tunnel is proposed byimproving the response deformation method. And the validity of the improved methodis verified.