高压水射流技术在混凝土结构养护维修、应急破拆中具有广阔应用前景。但高压水射流破除混凝土技术存在门槛泵压高，比能耗大，致裂可控性仍显不足等问题，这需对射流侵彻混凝土形态控制及损伤机理等进行研究。本项目结合试验测试、理论分析、数值模拟及优化技术，拟开展以下研究：①研究射流侵彻混凝土应变场、位移场分布特征与裂纹扩展形态之间关系，分析水锤效应下裂纹动态起始判据和应力波作用下裂纹传播规则，揭示应力波频谱特征对裂纹扩展形态影响机制。②研究射流侵彻下混凝土内部应力波波动周期、传播速度、衰减规律等动力响应特性，构建射流侵彻混凝土细观损伤数值模型，阐释射流致损混凝土力学机理。③研究射流弱作用区混凝土损伤分布规律及劣化特征，考察射流参数对混凝土的致损敏感性，建立基于多射流参数的高压水射流侵彻混凝土损伤预测模型。研究结果对促进射流破除混凝土技术发展，提高混凝土结构修复、救援破拆水平，具有重要科学意义和实用价值。

High pressure water jet technology has a broad prospect in concrete structure maintenance and emergency demolition. However, it still has some disadvantages, such as high threshold pump pressure, larger energy consumption and lack of controllability of crack. In order to solve these problems, it needs to find the mechanism of crack forms control and damage of high pressure water jet penetrating concrete. Theoretical analysis, experimental tests, numerical simulation, optimization technologies are carried out in this project. It establishes the relations among strain field, displacement field distribution characteristics and crack propagation forms, analyzes the crack dynamic starting criteria by water-hammer effect and crack propagation rule under stress wave, and studies the influence mechanism of stress wave spectrum characteristics on crack propagation. Then the fluctuation cycle, propagation speed, attenuation rule and other dynamic response characteristics of stress wave under water jet are researched, and a microscopic damage numerical model of high pressure water jet penetrating concrete is built, to reveal the damage mechanism of concrete under water jet. And it also studies the damage distribution and degradation characteristics in weak-effect zone of concrete penetrated by high pressure water jet, explores the sensitivity of water jet parameters to damaging concrete, and presents a damage prediction model of high pressure water jet penetrating concrete, with multiple parameters. The results will promote high pressure water jet breaking concrete technology, and they have important scientific significance and practical value to concrete structure maintenance and emergency demolition.