Impact of aftershocks on the response of a post-mainshock damaged metro station structure in seismic subsidence site

TY - JOUR

T1 - Impact of aftershocks on the response of a post-mainshock damaged metro station structure in seismic subsidence site

AU - Zhang, Zhongliang

AU - Cui, Zhendong

AU - He, Pengpeng

AU - Pak, Ronald Y.S.

N1 - Publisher Copyright: © 2026 Elsevier Ltd

PY - 2026/1/14

Y1 - 2026/1/14

N2 - This study investigates the impact of aftershocks on the seismic response of a post-mainshock damaged metro station structure, with a particular focus on the complex dynamic characteristics of seismic subsidence sites. A three-dimensional finite element model was developed to replicate the collapse evolution of a post-mainshock damaged metro station under aftershocks. The results show that under strong mainshocks, the aftershock-induced displacement increment ratio can reach 1.37. Even following a weak mainshock, aftershocks can trigger approximately 40% additional site subsidence. The structural uplift increment ratio decreases with increasing aftershock intensity ratio, with an average value of about 4.4%. The EPWP increment ratio can reach up to 2.4 during aftershocks. Notably, the damage evolution of metro stations exhibits a mainshock threshold effect, i.e., stronger mainshocks lead to earlier damage initiation, with damage ratios exceeding 30%. Critically, aftershocks can exacerbate the damage, forming pervasive damage zones. Importantly, the inter-story drift shows a positive correlation with the damage ratio, surrounding soil displacement increment ratio, and EPWP increment ratio. A modified damage index is proposed to accurately evaluate structural damage under mainshock-aftershock sequences. The findings provide a valuable reference for the seismic design and post-earthquake rescue of metro stations in urban soft soil areas.

AB - This study investigates the impact of aftershocks on the seismic response of a post-mainshock damaged metro station structure, with a particular focus on the complex dynamic characteristics of seismic subsidence sites. A three-dimensional finite element model was developed to replicate the collapse evolution of a post-mainshock damaged metro station under aftershocks. The results show that under strong mainshocks, the aftershock-induced displacement increment ratio can reach 1.37. Even following a weak mainshock, aftershocks can trigger approximately 40% additional site subsidence. The structural uplift increment ratio decreases with increasing aftershock intensity ratio, with an average value of about 4.4%. The EPWP increment ratio can reach up to 2.4 during aftershocks. Notably, the damage evolution of metro stations exhibits a mainshock threshold effect, i.e., stronger mainshocks lead to earlier damage initiation, with damage ratios exceeding 30%. Critically, aftershocks can exacerbate the damage, forming pervasive damage zones. Importantly, the inter-story drift shows a positive correlation with the damage ratio, surrounding soil displacement increment ratio, and EPWP increment ratio. A modified damage index is proposed to accurately evaluate structural damage under mainshock-aftershock sequences. The findings provide a valuable reference for the seismic design and post-earthquake rescue of metro stations in urban soft soil areas.

KW - Aftershock

KW - Metro station

KW - Seismic subsidence

KW - Uplift

KW - EPWP

KW - Damage index

UR - https://www.scopus.com/pages/publications/105027391502

U2 - 10.1016/j.tust.2026.107456

DO - 10.1016/j.tust.2026.107456

M3 - Article

SN - 0886-7798

VL - 171

JO - Tunnelling and Underground Space Technology

JF - Tunnelling and Underground Space Technology

M1 - 107456

ER -