管道破损引发渗流侵蚀过程的模型试验

城市道路下方埋设的市政管道发生破损后会引发渗流侵蚀并最终导致道路沉陷。针对此问题,本文建立了模拟管道破损引发渗流侵蚀的模型试验。试验结果表明,从地表以下由浅至深,土体受侵蚀区域可分为流动区域,粗粒化区域与空洞区域,其中前两者的范围大于第三者。水流失量与砂土流失量呈对数关系;空洞区域面积与砂土流失量呈线性关系,且低水位工况下单位砂土流失量所诱发的空洞区域面积大于高水位工况。同时,受不饱和区域及粗粒化区域中流失通道堵塞的影响,变水位工况中受侵蚀区域面积及水土流失量均小于相同水头高度下的恒水位工况。受侵蚀区域的土体贯入强度大幅降低(60%~80%),且其降低幅度受流动区域及粗粒化区域影响较大,受空洞区域影响较小。

Model Tests on Seepage Erosion Progress Caused by Damage of Municipal Pipeline

The damage of municipal pipeline buried under the urban road will lead to seepage erosion and road subsidence. In terms of this problem, a model test simulating the seepage erosion progress caused by pipeline damage is established. The results show that the eroded area can be divided into the flow area, coarse-grained area and void area respectively, and the ranges of the former two parts are larger than the third. The soil loss increases logarithmically with the water loss. The void area increases linearly with the soil loss. And the void area induced by the same amount of soil loss under low water level is larger than that under high water level. Meanwhile, due to the unsaturated area and blockage of flow path in the coarse grained area, the eroded area and the water and soil loss in the case of changing water level are less than those in the case of constant water level. The soil penetration strength in the eroded area is significantly reduced by 60%~80%. And the reduction is more significant in the flow area and coarse-grained area rather than in the void area.