To explore the
dynamic response of overlapped tunnels under the action of seismic loads and
provide a theoretical reference for the seismic design of overlapped tunnels,
the distribution laws for peak acceleration values of upper and lower tunnels
and crosssection of oblique overlapped tunnels are studied using a largescale vibration test platform under X unidirectional and XZ bidirectional ElCentro waves,
respectively. The results show that: (1) The peak acceleration at the central
crosssection of the overlapped tunnels is the highest,
whereas those at the crosssections of the ends of the
tunnels are significantly less; as such, the peak acceleration curve has a
parabolic shape, indicating that the crown of the overlapped tunnel would be
the weak point during earthquake resistance. (2) The seismic response of the
invert at the crosssection of the upper tunnel is
significantly weaker than that of the crown because of the undercrossing tunnel and spatial effect. Moreover, the dynamic response
at the central crosssection of the invert of the undercrossing tunnel is the lowest, indicating that the failure mode of
the invert shows a transmission evolution from both sides of the affected crosssection to the central crosssection. (3)
Superposition effect is observed in the acceleration response of the central
crosssection soil, leading to the strongest seismic
response at this point. However, the acceleration amplification factors of
other points decrease with increasing buried depth. (4) The dynamic response of
a point under the XZ bidirectional seismic wave is much higher than that under the X unidirectional [HJ]seismic wave,
especially when the seismic intensity is between 0.4 g and 0.6 g. Seismic
waves with different loading directions diversely affect the seismic response
at the invert of the overlapped tunnels.
LEI Hao
,
WU Honggang
,
MENG Qingyi
,
HE Changjiang
,
LI Dezhu
. Study on Seismic Dynamic Response of Oblique
Overlapped Tunnels[J]. Tunnel Construction, 2021
, 41(1)
: 88
-99
.
DOI: 10.3973/j.issn.2096-4498.2021.01.010
