When two
overlapped tunnels crossing with small distance and angle, the underpassing
tunnel construction has a significant impact on the stability of the existing
operating tunnel. In this paper, a case study is conducted on Qingdao North
stationCang′an Road station of
Qingdao metro line 8 obliquely crossing underneath adjacent existing tunnel of
Qingdao metro line 3, and the ABAQUS is used to establish a finite element
calculation model to analyze the vertical and horizontal displacement and
stress evolution laws of the existing tunnel in the process of new tunnel
excavation. The settlement displacement of the existing upper tunnel structure
is monitored in real time during construction, and the difference between
monitoring data and simulation results is compared and analyzed. The results
show the following: (1) The most dangerous crosssection
of the existing tunnel is located at the intersection of the upper and lower
tunnels, and the excavation range of the crosssection
of the existing tunnel with most adverse condition is 20
m ahead of and behind the crosssection of the new tunnel at intersection. (2) In a same tunnel crosssection, the underpass tunnel construction will cause displacement
of the arch and the left waist and the arch bottom and the right waist in the
existing tunnel in an opposite direction, and the existing tunnel structure
crosssection has a tendency of torsional deformation.
(3) The excavation of new tunnel has little influence on the maximum principal
tensile stress and compressive stress of existing tunnel, and the tunnel bottom
plate has a larger stress.
ZHANG Qing, WANG Hongchao, ZHAO Yao, SHAO Jingqi, GAO Ziming, ZHANG Lianzhen, CHEN Jian, WANG Chong, YU Lei
.
Stability Analysis of New Tunnel Obliquely Crossing underneath Adjacent Existing Tunnel with Small Angle: a
Case Study of a Tunnel of Qingdao Metro Line 8
[J]. Tunnel Construction, 2021
, 41(S2)
: 199
-208
.
DOI: 10.3973/j.issn.2096-4498.2021.S2.025
