A one-dimensional unsteady compressible nonisentropic flow model,
incorporating a generalized Riemann variable characteristic line numerical
simulation method and the rain flow counting method, is employed to explore the
mechanisms and characteristics of pressure fluctuations at the center and
inside the entrance and exit of a tunnel during the passage of a single train
and the crossing of two trains at the same speed. The distribution patterns of
the maximum positive and negative pressures, the maximum pressure peak-to-peak values at various measurement points
inside the tunnel along its length, the influence of tunnel length on the
maximum tunnel aerodynamic load, the impact of train speed on the magnitude,
position, and frequency of amplitude, and the distribution characteristics of
the critical tunnel length based on the maximum pressure peak-to-peak value inside the tunnel are
obtained. The research results demonstrate the following: (1) The pressure at a
given location in the tunnel measurement points remains constant for a certain
time when a single train passes through and when two trains cross at a constant
speed. After the train exits the tunnel, the pressure waveform repeats
periodically, consistent with the propagation period of the compression or
expansion wave inside the tunnel. (2) When a single train passes through a
tunnel at three different speeds and tunnel lengths ranging from 0.5 to 10 km,
the maximum positive pressure value occurs 200－600 m
from the tunnel entrance. As speed increases, the position of the maximum
negative pressure value and the pressure peak-to-peak value for certain tunnel lengths shift from the near-inlet side toward the near-exit side of the
tunnel center. (3) At 400 km/h speed, the critical tunnel length based on
different maximum pressure loads is 1.3 km for a single train passage and 1.4,
0.94, and 1.2 km for the central meeting of two trains at a constant speed. (4)
The highest amplitude levels for single train passage and central meeting of
two trains at 400 km/h can reach 4 800 to 5 200 Pa and 10 000 to 10 400 Pa,
respectively.
LIANG Zhenglong
,
YANG Yang
,
WEI Kang
,
DU Yunchao
,
MEI Yuangui
.
Characteristics and Distribution Pattern of Surface Aerodynamic Load on Lining of 400 km/h High-Speed Railway Tunnels
[J]. Tunnel Construction, 2024
, 44(7)
: 1465
-1476
.
DOI: 10.3973/j.issn.2096-4498.2024.07.013
