In order to analyze the influence of adjacent
overcrossing construction of a newlybuilt tunnel on existing
tunnel, a 3D FEM model is established to simulate the large crosssection Hongyancun Highway Tunnel (HHT) crossing above the existing
Rail Transit Loop Line Tunnel (RTLLT) in Chongqing with the minimum vertical
clear spacing of 0.33 m. And
the distribution and variation laws of stress and deformation of the secondary
lining of RTLLT are obtained and analyzed. The results show that: (1) When the
bench method is used for HHT, the influence of excavation of top heading and
middle bench on the RTLLT is the largest, while that of the excavation of lower
bench is the smallest. (2) The deformation of RTLLT is characterized by
vertical deformation, and the maximum values locate at the four crossing
sections of the RTLLT right below the HTT, where cracks might appear in the
secondary linings due to the large tensile stress. In addition, the stress and
deformation variation of RTLLT can be divided into three stages with the
excavation of HHT, and the 58meterlong core excavation control region for HHT can be determined.
Accordingly, the construction control area is divided and different
construction methods such as controlled blasting with second delay detonators
and mechanical excavation are used to ensure the successful overcrossing
construction of HTT.
WANG Yong, WANG Guoxin, LI Jinhui, SU Jinggao, LI Shuyu, DING Ya
.
Influence of Overcrossing Construction of a Newlybuilt
Highway Tunnel on Existing Metro Tunnel with Small Clear Spacing: a Case Study on Chongqing Hongyancun Tunnel
Overcrossing
Existing Loop Tunnel
[J]. Tunnel Construction, 2020
, 40(S1)
: 160
-168
.
DOI: 10.3973/j.issn.2096-4498.2020.S1.020
