隧道壁面瞬变压力及其对隧道结构安全的影响

Pressure waves acting on wall of a tunnel and their impact on the tunnel's structural safety

本文采用三维数值方法分析了列车通过隧道引发的洞壁瞬变压力及其对隧道衬砌结构安全的影响。结果表明:单车通过隧道时,随着测点距离隧道入口距离的增加,隧道壁面压力迅速增加,在距隧道入口200 m位置达到最大;两列车在隧道内交会时,隧道壁面最大压力出现在隧道中部。列车以350 km/h速度单车通过70 m^(2)单线隧道、100 m^(2)双线隧道和两车在100 m^(2)双线隧道内交会时,隧道壁面最大峰值压力分别为−4544 Pa,−3137 Pa和−5909 Pa;在隧道气动载荷作用下,隧道衬砌上的轴向力分别仅为岩土压力的8%、5%和9%。若不考虑气动载荷对隧道衬砌裂纹和缺陷的影响,气动载荷对隧道衬砌静强度安全系数的影响不大。

The transient pressures induced by trains passing through a tunnel and their impact on the structural safety of the tunnel lining were numerically analyzed.The results show that the pressure change increases rapidly along the tunnel length,and the maximum value is observed at around 200 m from the entrance,while the maximum pressure amplitude is detected at 250 m from the entrance when two trains meeting in a double-track tunnel.The maximum peak pressure on the tunnel induced by a train passing through a 70 m^(2) single-track tunnel,100 m^(2) double-track tunnel and two trains meeting in the 100 m^(2) double-track tunnel at 350 km/h,are−4544 Pa,−3137 Pa and−5909 Pa,respectively.The aerodynamic pressure induced axial forces acting on the tunnel lining are only 8%,5%and 9%,respectively,of those generated by the earth pressure.It seems that the aerodynamic loads exert little underlying influence on the static strength safety of the tunnel lining providing that the existing cracks and defects are not considered.