施工车辆荷载对隧道内煤系地层的影响规律研究

Research on influencing law of construction vehicle load on coal measures strata in tunnels

为了研究在建隧道内的煤系地层在施工车辆振动荷载下的变形规律,以某公路隧道为工程背景,构建了施工车辆荷载作用于隧道煤系地层的数值模型,并采用多物理场仿真软件COMSOL进行了求解计算,分析了施工车辆载重、行车速度、行车次数、煤岩位置与不同深度5个因素对隧道煤系地层变形的影响规律。研究结果表明,随着施工车辆载重的增加,隧道内煤系地层的位移响应与塑性应变量呈现先急剧增大、后增加趋势减缓的变化规律;施工车辆行车速度对煤系地层位移与损伤影响较弱;煤系地层位移量随车辆往返次数依次经历剧增加、缓慢增加、降低与稳定4个阶段,塑性应变呈4个阶梯增加;隧道底部越浅处的煤层受车辆振动荷载影响越大,导致其变形程度越大。研究结果可为瓦斯隧道安全施工提供一定的理论佐证。

In order to study the deformation of coal stratum in tunnel under the vibrating load of construction vehicles,a numerical model of the tunnel containing coal stratum under the dynamic load of construction vehicles is established based on a highway tunnel project,and the multi-physical field simulation software COMSOL was used to calculate the model.The influence rules of five factors including the load of construction vehicles,driving speed,application times,coal and rock location and different depths on the deformation of coal stratum in tunnel are analyzed.The results show that with the increase of the load of construction vehicles,the displacement response and plastic strain of coal measure strata in the tunnel increase sharply at first and then decrease.The driving speed of construction vehicles has weak influence on the displacement and damage of coal measure strata.The displacement of coal measure strata experienced four stages of rapid increase,slow increase,decrease and stability with the number of vehicle round trips,and the plastic strain increased in four steps.The shallow coal seam of tunnel bottom is much easier to be disturbed by the vehicle load,which at last leads to a larger deformation.The research results can provide some theoretical evidence for the safe construction of gas tunnel.