In this study, the air
resistance inside a tunnel is decomposed into the resistance of the train head
and tail due to the pressure differential, friction resistance of the carriage,
pressure differential resistance of the entire train, and resistance of the air
gravity around the train along the train′s
direction of travel. A research method for calculating the air resistance
within a single-sided slope tunnel that considers the
slope of the tunnel is established using the characteristic line of a one-dimensional compressible flow model with unsteady entropy. These aim
to explore the effects of the tunnel length, slope, shape of the slope, train
speed, and altitude on the average air resistance, maximum air resistance,
tunnel average air resistance factor, and maximum air resistance factor when a
train passes through a high-speed railway tunnel in
plateau area. The findings are as follows. (1) The pattern of variation in air
resistance in a sloped tunnel when a train passes through it is related to the
pressure wave outside the train and the air resistance of the gravity
component, and the air resistance increases or decreases under the action of
compressive and expanding waves. When a train passes through a singlesided uphill/downhill tunnel, a tunnel with a herringbone slope, or
straight tunnels having different tunnel lengths, the most unfavorable slope
type and critical tunnel length based on average air resistance exist. The
average air resistance over the length of a 10 km long, single-sided uphill tunnel is at its highest when a train is passing
through it, reaching 47.05 kN. (2) When a train passes through a single-sided, uphill tunnel, the average air resistance and maximum air
resistance increase as the slope of the tunnel and the speed of the train
increase, and they decrease as the altitude increases. Additionally, when the
average air resistance is fitted to the train speed, the average air resistance
inside a single-sided, uphill/downhill tunnel when a
train is passing through it is approximately proportional to the power of 1.92
and 2.14 of the speed, respectively.
DENG Hong
,
WAN Youcai
,
MEI Yuangui
. Variation Pattern in Air
Resistance of a Train Passing Through Long and Extra-Long High-Speed
Railway Tunnels in Plateau Areas[J]. Tunnel Construction, 2024
, 44(7)
: 1491
-1501
.
DOI: 10.3973/j.issn.2096-4498.2024.07.015
