In this paper,
a case study is conducted on the Qiyueshan tunnel of the Moudao connecting line
project on the LichuanWanzhou expressway. The conditions
of the 26 karst caves exposed during tunnel construction are investigated, and
the development scale, filling characteristics, waterbearing
characteristics, development location, and geological origin of karst caves are
analyzed. Furthermore, the influence of the superlarge
karst cave on the tunnel surrounding rock deformation is studied using
numerical simulation, and the treatment technologies of karst caves in
different positions of the tunnel are discussed through case analysis. The results reveal the following: (1) In
exposed karst caves, the mediumscale one is the most
common, followed by largescale one, and the smallscale and superlarge scale ones are the
least common; the exposed karst caves are mostly dry with no or partial
filling, and the development location mainly concentrates on the tunnel face.
(2) The climate and hydrogeological conditions at the tunnel site are favorable
for karst development, but due to the high tunnel elevation and groundwater
level lower than the design level, no waterbearing
karst cave is exposed. (3) The surrounding rock displacement at the junctions
between the karst cave and tunnel is the largest, so the support should be
strengthened. (4) The treatment techniques and principles of karst caves of
various sizes and locations are developed and applied to engineering practice.
The subsequent operation results validate the feasibility of the treatment
methods. It is proposed that normalized advance detection, standardized
treatment process, modular treatment technique, and targeted treatment scheme
should be established for karst cave treatment.
ZHAO Shaozhong
,
HUANG Xin
,
XU Zhenhao
,
LI Minghai
. Development Characteristics and Treatment Techniques
of Karst Caves in Qiyueshan Tunnel[J]. Tunnel Construction, 2022
, 42(7)
: 1289
-1299
.
DOI: 10.3973/j.issn.2096-4498.2022.07.017
