Rational geometric parameters of spiral highway
tunnels are essential for traveling safety of vehicles. Herein, data research
and theoretical analysis are employed to establish the relationship between
tunnel alignment and accident rates. Then, factors affecting tunnel slope,
length, and curvature radius are identified, and the threshold values for slope
and slope length under different influencing factors are analyzed. The results
show the following: (1) Under the same longitudinal slope, downhill sections
exhibit a higher accident rate than uphill sections. Under the same slope,
trucks are more affected by slope length, and the accident rate increases
sharply when the tunnel′s curvature radius is less than 600 m. (2) The factors affecting tunnel slope
primarily include locomotive climbing performance, climbing balance speed,
allowable climbing speed, and operational ventilation. The factors affecting
slope length is brake temperature, while the factors influencing curvature
radius primarily include vehicle headlight scattering angle, sight distance,
cross slope, driving safety, and operational ventilation. (3) Based on factors
affecting tunnel slope, the threshold for the longitudinal slope of spiral
tunnels with large longitudinal slope and small-radius
is determined. Using a brake hub temperature of 200 ℃ as a control benchmark, and in combination with safety evaluation criteria,
tunnel slope length thresholds for different slopes and design speeds are provided. Additionally, based on
factors influencing curvature radius, the curvature radius threshold for spiral
tunnels with large longitudinal slope and small-radius
is established. (4) Based on the threshold values for slope, slope length, and
curvature radius, the maximum allowable longitudinal slope, design speeds for
different slopes, and geometric design recommendations for spiral tunnels with
large longitudinal slope and small-radius are provided.
WANG Jian
,
CHEN Weitao
,
HUANG Peng
,
ZHANG Lixiang
,
YU Li
,
WANG Xue
,
LIU Yuan
,
LI Junqi
,
WANG Song
. Geometric Parameters of Spiral Highway Tunnels With
Large Slopes and Small Radius[J]. Tunnel Construction, 2025
, 45(S1)
: 193
-207
.
DOI: 10.3973/j.issn.2096-4498.2025.S1.020