To study the influence of concealed karst caverns on
the stability of metro shield tunnel, the karst caverns distribution of a metro
shield tunnel on Lianda Street StationWujiaying Station of Kunming
Rail Transit Line 4 located in the plateau karst Development area are explored
using borehole geophysical prospecting and electromagnetic CT methods. The
threedimensional finite element numerical simulation
method is adopted to study the influence of lower karst caverns on stability of
shield tunnel with different burial depths and that of karst cavern radius,
state of karst cavern filling, position of karst cavern and spacing between
karst cavern and tunnel on the stability of shield tunnel. Then the stability
of tunnel structure in karst development area during construction process is
analyzed as well. The results show following. (1) The karst caverns
distribution can be well explored using borehole geophysical prospecting and
electromagnetic CT methods. (2) When the size and position of the karst cavern
remain unchanged, the plastic zone and deformation of the surrounding rock of
the shield tunnel increase with the increasing burial depth of karst cavern.
(3) With the increase of karst cavern radius, the stress concentrated area
between tunnel and karst cavern becomes dispersed, and the deformation of
tunnel surrounding rock decreases. (4) The materials and amount of filler in
the karst cavern has no effect on the deformation of surrounding rock of
tunnel. (5) The influence degree of karst cavern at the both sides of tunnel on
the deformation of tunnel surrounding rock is greater than that of karst cavern
below tunnel, and that of karst cavern below tunnel is greater than that of
karst cavern above tunnel. (6) The karst cavern would affect the tunnel
construction within a certain spacing between tunnel and karst cavern.
Daoyan
,
XIE Jianbin
,
LI Zhong
,
SUN Xiaohai
.
Numerical Analysis on Influence of Concealed Karst Caverns
upon Stability of Metro Shield Tunnel
[J]. Tunnel Construction, 2020
, 40(S2)
: 151
-160
.
DOI: 10.3973/j.issn.2096-4498.2020.S2.020
