Discuss On The Seismic Design Simplified Method Of Subway Station Structures In Loess Area

Considering the underground of three spans of two layers typical subway station structure in the loess area of Xi’an, in order to get the simplified calculation method, finite element software ANSYS is used to establish the two-dimensional numerical model of subway station structure under the action of horizontal seismic. Conclude the maximum displacement between layers of the station structure under the action of horizontal seismic through the dynamic and time-historical analysis, and which is as the response displacement applying to the typical response displacement method. The results of calculation analysis show that:1.The most stress concentration parts is the connection of plate-wall and plate-column of the subway station structure under the action of horizontal seismic, time history curves of the acceleration, velocity, displacement of the these parts are similar, and there is little difference among the peak stress response. But compared with the input peak acceleration, the amplification effect of the peak acceleration response is significant, the maximum displacement between layers is occurring at time 5s.2.The simplified calculation method of this paper is established on the basis of the traditional response displacement method, applying the maximum inter-layer displacement under the dynamic and time-historical analysis to the subway station structure. At the same time, the factors such as seismic inertial force, water and soil pressure and gravity stress are considered. The internal force values of the structure of the station are calculated by the displacement method which is used to calculate the internal force of statically indeterminate structure in structure mechanics, the calculation method is simple. The process of the calculation is clear, the result of the calculation is relatively reasonable.3.Compared with the results of dynamic and time-historical of ANSYS numerical model, the results of simplified calculation method in this paper is overall bigger than most others. That is mainly because considering the biggest displacement between layers of the structure(the most dangerous situation) in the process of calculation, and the earthquake acceleration value is also the input maximum acceleration of the dynamic time history, so the calculation results is larger, which will make the engineering design more safety.