交通荷载下城市路面塌陷问题的试验研究

地下管线渗漏与交通荷载是引起城市道路塌陷的重要原因。本文采用8组室内缩尺模型试验,考虑了荷载类型、管线埋深、管线与流失通道间距、管线与流失通道相对位置和流失通道形成时间等因素,研究了管线渗漏引起的路面坍塌问题。试验结果表明:当流失通道形成较晚时下伏侵蚀空洞呈球形,其余情况下侵蚀空洞形状皆为漏斗形;仅有静荷载作用时,达到最终破坏的时间比仅有动荷载作用时要长;较小的动荷载,能增加渗漏管线上方土体的稳定性,而较大的动荷载则加快了路面塌陷过程;随着流失通道形成时间的增加,形成侵蚀空洞尺寸就越大,地表越容易塌陷;随着流失通道与管线的间距增加,最终路面破坏时长也增加;位于管线上方的土层厚度越大,地下空洞尺寸和地表沉降就越小。

Model Experiments on Ground Collapse under Traffic Roads

Underground pipeline leakage and traffic load are important factors that lead to ground collapse. In this paper, 8 sets of indoor scale model tests were adopted to consider, such factors as load type, buried depth of pipeline, distance between pipeline and drain channel, relative position between pipeline and drain channel and formation time of drain channel. The experimental results show that when the erosion channel is formed late, the underlying erosion cavity is ellipsoid, and the other erosion cavities are funnel shaped. When only static load is applied, the final destroy time is longer than when only dynamic load is applied. When the dynamic load is small, the stability of soil above the leaking pipeline can be increased, while when the dynamic load is large, the collapse process can be accelerated. As the formation time of loss channel increases, the size of erosion cavity becomes larger and the surface is more prone to collapse. The distance between the loss channel and the pipeline is increased, and the final road damage time also increases. The greater the thickness of the soil layer above the pipeline, the smaller the size of underground cavity and surface subsidence.