Seismic responses of a complicated subway underground station in soft soil layers

Soft soil layer has important influence on seismic responses of underground structure. In the past, seismic responses of regular rectangular subway station in soft soil base were studied, but if their laws are suitable for underground structures with complex cross-section needs to further explore. Here, considering there were 27 soft soil sites with different buried depth and different thickness of soft soil layer at the side and the bottom of a new subway underground station structure, seismic responses of this station with 5 spans in its upper floor and 3 spans in its lower floor were studied. Influence laws of soft soil layer buried depth and its thickness on the station structure's acceleration responses, lateral displacement responses and seismic damage features were deduced preliminarily. The results showed that when soft soil layer exists within a certain range of two sides or bottom of the station structure, acceleration responses of the station with different spans may be reduced; when there is a soft soil layer 20 meters below the bottom of the station, its top acceleration is amplified by 7.88%-12.72%; the station lateral displacement curve changes along the height with an obvious step effect; soft soil layer existing at the station lateral is not good for anti-earthquake of the station; when soft soil layer exists at the station lower floor lateral, dynamic responses of the station are larger; soft soil layer existing below the bottom of the station can have a certain seismic isolation effect on the station. © 2019, Editorial Office of Journal of Vibration and Shock. All right reserved.