地下水力管线外渗引起的道路塌陷机理模型试验  

Model Test Investigation on Mechanism of Road Collapse Induced by Underground Hydraulic Pipe Leakage

作　　者：戴自立 彭凌豪 包扬娟 DAI Zi-li;PENG Ling-hao;BAO Yang-juan(School of Mechanics and Engineering Science,Shanghai University,Shanghai 200444,China;School of Civil Engineering and Architecture,Zhejiang University of Science and Technology,Hangzhou 310023,Zhejiang,China)

机构地区：[1]上海大学力学与工程科学学院,上海200444 [2]浙江科技学院土木与建筑工程学院,浙江杭州310023

出　　处：《中国公路学报》2024年第10期49-60,共12页China Journal of Highway and Transport

基　　金：上海市2021年度“科技创新行动计划”社会发展科技攻关项目(21DZ1204202);国家自然科学基金青年科学基金项目(42302307)。

摘　　要：道路塌陷是一种常见的城市地质灾害,对城市安全构成巨大威胁。为探讨道路塌陷的形成机理,设计了一套模型试验装置来研究地下水力管线外渗引起的土体冲蚀区和塌陷坑的演化规律,通过孔隙水压力传感器和位移传感器定量分析管道外渗引起的孔隙水压力和路面位移变化特征,并探究了管内水流速度、管道埋深、土体初始含水率以及缺陷位置4个因素对土体冲蚀过程和塌陷坑形态的影响。模型试验再现了地下水力管线外渗引起路面塌陷的全过程,分为初始渗透、缓慢位移、稳定冲蚀3个阶段;分析了管线缺陷上方锥形冲蚀区的形成过程及其影响因素,发现冲蚀角与土体初始含水率无关,管道埋深越深,管道水流速度越小,冲蚀角越小;建立了流化冲蚀区水土混合物的受力平衡方程;研究了不同因素对塌陷坑形态的影响规律。研究结果表明:塌陷深度和面积与管内水流速度正相关;塌陷坑宽度与管道埋深呈线性关系;土体初始含水率越大,塌陷坑的深度越小,塌陷面积越大;缺陷位于管道底部时塌陷深度最小。Road collapse is a typical geological disaster that threatens urban safety.To investigate the formation mechanism of road collapse,a model test apparatus is designed to understand the formation mechanisms of soil-erosion areas and collapse pits resulting from hydraulic pipeline leakage.The change characteristics of pore-water pressure and surface displacement caused by underground hydraulic pipeline extravasation are quantitatively analyzed using pore-water pressure and displacement sensors.The effects of four parameters on the soil-erosion process and the formation characteristics of collapse pits are investigated:the flow velocity of the pipeline water,the buried depth of the pipeline,the initial water content of the soil,and the defect position.The model experiment replicates the entire process of pavement subsidence induced by pipeline leakage,which can be classified into three stages:initial seepage,slow displacement,and stable erosion.The formation process of the conical erosion area above the pipeline defect and its influencing factors are analyzed.Based on observation,the erosion angle is independent of the initial moisture content of the soil,and as the pipeline burial depth increases,the flow speed within the pipeline decreases,thus consequently reducing the erosional angle.An equilibrium equation is derived for the sand-water blend in the fluidized erosion zone.The effects of these three parameters on the morphology of the collapse pit are discussed.The results show that the water-flow velocity inside the pipeline is positively correlated with both the depth and area of the collapse,and that a linear relationship exists between the pipeline burial depth and collapse width.The higher the initial moisture content of the sandy soil,the smaller is the collapse depth and the larger is the collapse area.The collapse depth is minimum when the defect is located at the bottom of the pipeline.

关 键 词：路基工程 道路塌陷机理 模型试验 土体冲蚀 管道渗漏 

分 类 号：U416.1[交通运输工程—道路与铁道工程]