高海拔、高流速条件下泄水构筑物抗冲磨混凝土裂缝控制研究

There has been a serious contradiction between early-age crack and the high requirements of abrasion resistance and durability for the drainage structure with high flow velocity in high altitude area, which is a significant theoretical and practical issue and should be solved urgently. Shrinkage deformation is one of the most important reasons for early-age abrasion resistance concrete crack. However, the crack prevention of shrinkage deformation has not been well developed yet. After pouring, the concrete structure undergo the multi-field coupling condition of hydration, temperature, humidity and mechanics. By which, the risk assessment results of shrinkage crack are quite different compared with that under the condition of single factor. Theoretical and experimental researches will be adopted in this project to build multi-field coupling mechanism of hydration, temperature, humidity and mechanics, which will consider the environment effects of high altitude and the component characteristics of abrasion resistance concrete materials. And the evolution law of temperature and humidity transmission and distribution will be revealed. Further, the anti-crack evaluation and design method of drainage structure will be proposed, in which the influence factors of material properties, environmental conditions, surrounding rock types, size effects and construction technologies will all be considered. Based on the synergy-regulation technology of temperature field and expansion history, a new technology of improving cracking assistant will be developed. And a complete set of crack prevention technical schemes of the abrasion resistance drainage structures will be proposed with constructive technologies. The research achievements could provide theoretical basis and technical support for early-age cracking control of abrasion resistance concrete, assurance of construction quality and service life of the drainage structures with high flow velocity in high altitude area.

高海拔、高流速条件下泄水构筑物抗冲磨混凝土早期开裂与其本身要求的高抗冲磨、高耐久性之间存在严重矛盾，是亟需解决的重大理论和技术问题。收缩变形是抗冲磨砼早期开裂主要原因，但有关其收缩变形裂缝控制至今未能很好解决。浇筑成型的砼结构处于水化-温-湿-力多场耦合作用环境，与仅考虑单一因素的收缩开裂评估结果之间存在很大差异。本课题拟通过理论和试验研究，构建考虑高海拔环境和抗冲磨砼材料组成特点的水化-温-湿-力多场耦合作用机制；揭示抗冲磨砼温湿度传输与分布规律，提出综合反应材料性能、环境条件、围岩类别、尺寸效应、施工工艺等因素影响的泄水构筑物抗冲磨砼抗裂性评估和设计方法；研究基于温度场与膨胀历程协同调控的抗冲磨砼抗裂性提升技术，结合施工工艺措施，提出泄水构筑物抗冲磨砼成套防裂技术方案。研究成果为全面控制高海拔、高流速条件下泄水构筑物抗冲磨砼早期开裂、保障工程建设质量与服役寿命提供理论基础和技术支撑。

高海拔、高流速条件下泄水构筑物抗冲磨混凝土早期开裂与其本身要求的高抗冲磨、高耐久性之间存在严重矛盾，是亟需解决的重大理论和技术问题。收缩变形是抗冲磨砼早期开裂主要原因，但有关其收缩变形裂缝控制至今未能很好解决。本课题经过3年持续不断深入研究，取得如下成果：（1）开展了抗冲磨混凝土早龄期水化历程、微结构形成与演变研究，构建了水化-温-湿-拉应力多场耦合作用机制；（2）开展了水化-温-湿-力耦合作用的收缩开裂模型构建研究，研究了开裂风险评价指标及其阈值的取值，提出综合反应材料性能、环境条件、围岩类别、尺寸效应、施工工艺等因素的泄水构筑物抗冲磨混凝土抗裂评估和设计方法；（3）开展了水化热调控材料与钙镁质膨胀材料对混凝土温度场、体积变形试验研究，阐明了温度场与膨胀历程协同调控作用机制；（4）依托两河口水电站工程开展了现场试验研究，原位、实时监测泄水构筑物实体结构抗冲磨混凝土自浇筑后的温度、湿度、应变等的变化历程，提出了泄水构筑物抗冲磨混凝土裂缝控制技术。.在基金资助下参加了在6th International Conference on Architecture, Civil and Hydraulic Engineering (ICACHE 2020)会议，作报告“Investigation of moisture transport in cement-based materials using LF-NMR imaging” ，并于2019年12月~2020年12月赴美国俄勒冈州立大学进行访学，合作导师J. Weiss教授，开展内养护混凝土力学与体积变形方面的研究。.在基金资助下已发表SCI论文11篇，中文EI论文1篇，授权发明专利5项，参编行业标准1部、省级团体标准1部，出版专著2部（分别为第1、2作者），获省部级科技进步奖二等奖2项（排名分别为2、3）。以项目研究为依托，毕业硕士研究生17名，培养博士研究生2名。根据本课题研究成果凝练的“现代混凝土结构施工期裂缝防控基础理论与关键技术”，应用于上海市新川沙泵闸、两河口水电站等大型工程中，对土木、水利工程行业的科技进步具有推动作用。