The grade Ⅵ surrounding rock at mix zone
of slope wash soil and mudslide accumulation with shallow overburden and asymmetrical
pressure at tunnel entrance is prone to collapse and landslide, resulting in
difficult tunnel entering. As a result, the construction difficulties and rapid
tunnel essential entering technologies of a plateau railway are studied. Main
studies and conclusions are as follows: (1) The advance large pipe roof is
employed to improve the surrounding rock strength at 30 m section of tunnel
entrance. (2) 11 end piles and 34 t friction piles are arranged at tunnel
entrance and sideslope respectively to solve asymmetrical pressure problem. (3)
1 054 jet grouting piles are arranged within 90 m zone on tunnel top to improve
the stability of slope wash soil; a 198 mlong aqueduct
is adopted to drain the water on tunnel top right, and the aqueduct is arranged
at top of retaining wall innovatively to reduce the mudslide risk in rainy
season. (4) The advance smallduct reinforcement and
cantilever boring machine are adopted at grade Ⅵ surrounding rock at 30 m mix zone of tunnel entrance to minimize disturbance to
surrounding rock; the construction sequence is improve from opencut first and then mining to mining first and then opencut according to construction requirements in winters. The
application results show that the methods recommended can minimize the
influence of tunnel entering construction on surrounding environment, shorten
the construction period, and guarantee the construction safety.
YU Jingbo
,
LI Zhijun
,
WANG Qiulin
,
REN Ruile
,
LIU Guangzhi
,
LI Wutao
,
LYU Zheng
,
SUN Wei
. Tunnel Entering Construction Technology in Slope Wash
Soil and Mudslide Accumulation Mix Zone with Shallow
Overburden and Asymmetrical Pressure[J]. Tunnel Construction, 2022
, 42(S2)
: 428
-434
.
DOI: 10.3973/j.issn.2096-4498.2022.S2.053
