To optimize the
crosssection shape of squeezed surrounding rock tunnels under large
deformation pressure, the crosssection shapes of
single-and doubletrack railway tunnels are determined
based on the construction clearance of passenger and freight railway tunnel
with a speed of 200 km/h. Economic and safe crosssection
types of single-and doubletrack railway tunnels under
various deformation levels are proposed through structural safety evaluation.
The conclusions are drawn as follows: (1) With an increase in deformation
level, the structural load increases and the structural safety coefficient
decreases evidently. The most economical tunnel crosssection
proposed based on the construction clearance cannot meet the structural safety
requirements. (2) The arch and wall feet are the weak parts of the tunnel
structure. By optimizing the curvature of tunnel crosssection,
the smooth connection between arch and sidewall and that between sidewall and
inverted arch can be realized, thus effectively improving the stress state of
the structure and the structural safety. (3) For single track tunnel: singletrack A crosssection type (connected with
the normal singletrack tunnel section) is recommended
for grade I deformation, singletrack B crosssection type (optimized crosssection
curvature based on singletrack A crosssection) is recommended for grade II deformation, and singletrack E crosssection (circular) is
recommended for grades III and IV deformation. (4) For doubletrack tunnel: doubletrack C crosssection type (crosssection curvature
optimized on the basis of conventional doubletrack
tunnel) is recommended for grades I and II deformation, and doubletrack E crosssection (circular) is
recommended for grades III and IV deformation. (5) In engineering practice, the
crosssection type should be comprehensively optimized
considering structural safety, zone connection, and construction convenience.
Under grade IV deformation condition, strengthened grouting reinforcement,
multilayer support, and stress release should be
conducted to ensure the safety of the tunnel structure.
YANG Bin, LIU Tianci, LIU Zhichun, LI Ning, DUO Shengjun
.
CrossSection Shape Optimization Design of
Railway Tunnel in
Squeezing Rock Based on Deformation Classification
[J]. Tunnel Construction, 2023
, 43(S1)
: 344
-355
.
DOI: 10.3973/j.issn.2096-4498.2023.S1.040
