Train-induced Vibration Response and Sensitivity Analysis of New Underpass underneath the Subway

This paper analyzes the influence of different factors on the train-induced vibration response of newly-built underpass. These factors include the train operation mode (T), train speed (V), the thickness ratio of the underpass roof slab to the upper station floor slab (R_RF), the thickness ratio of the middle wall to the side wall of the underpass (R_MS), and the void defect between the underpass roof and the upper station floor (V_RF). On this basis, the sensitivity of the above factors to the underpass vibration response induced by existing trains is discussed. The results demonstrate that all the above factors have a great effect on the peak acceleration and peak amplitude of the underpass roof. The calculation results of T show no significant differences. Both peak acceleration and amplitude increase rapidly and non-linearly with increasing V. The acceleration response and peak amplitude of the underpass can be significantly reduced by R_RF and R_MS but aggravated by V_RF. The acceleration response distribution of the underpass is always symmetrical, and these factors have little influence on this symmetrical. Based on preliminary design parameters, the sensitivity of these factors on the acceleration response of underpass is ranked as V > R_RF > V_RF > R_MS > T.