本项目以我国城市地下水管泄漏导致的地陷事故逐年增多、其工程危害日益凸显的现状为背景，针对现有研究的不足，基于土力学与流体动力学的理论基础，采用“试验+分析→模型→应用”的研究思路，结合计算机数值仿真与物理模型试验，致力于研究地下水管泄漏所致砂土的基本破坏模式，并深入细观层面分析其发生机制及演化规律。首先，通过对多种渗流模态下流土临界孔隙水压差与管道内外压差的试验研究，建立砂土在泄漏水流作用下的流土临界状态预测模型。其次，通过分析研究空洞形成至稳定过程中流场分布、空洞上部应力分布、土颗粒粒间接触力分布随时间的变化规律，建立基于颗粒层面的空洞演化与稳定细观力学模型。再次，通过管涌型砂土在泄漏水流作用下的潜蚀破坏试验，阐明此类潜蚀破坏的发生机制与演化规律。最终，建立与完善地下水管泄漏所致的砂土破坏机理与预测模型，为有效预测和控制由地下水管泄漏引发的城市设施破坏与安全事故提供理论指导依据。

Leakage from underground pipes could result in foundations being undermined and damages to adjacent infrastructures. Such hazards are increasingly encountered in the modern cities in China. Due to the existing research gaps in the area of soil-leakage interaction, the project aims to investigate the mechanism underlying the initiation and progression of the leakage-induced sand failure. Based on the fundamental theories in soil mechanics and fluid dynamics, the project is engaged to build up a prediction model for the critical state of sand fluidization by studying on the pore pressure drop across the bed as well as the pressure difference across the orifice. Moreover, the flow field, stress field, and inter-particle forces are going to be explored during the formation of stable cavity due to fluidization, and a mechanical model on the particle level is going to be established for cavity evolution and stabilization. In addition, the suffosion mechanism and its progression induced by a pipe leakage are also of special interest in this project. Following the flow of ‘experiments + analyses → models → application’, the study is going to be carried out with numerical simulation and model tests adopted as main methods. The outcome of this project would be able to bring more complete and in-depth understanding of the soil-leakage interaction, and to provide effective practical instructions for prediction and control of the hazards caused by an underground leaking pipe.