快速浇筑条件下混凝土坝施工期温度与应力特性和防裂方法  

Temperature and Thermal Stress Characteristic and Cracking Prevention for Concrete Gravity Dam Under Fast Pouring Method

作　　者：王海波[1] 强晟[2] 王仁坤[1] 

机构地区：[1]中国电建集团成都勘测设计研究院有限公司,四川成都610072 [2]河海大学水利水电学院,江苏南京210098

出　　处：《应用基础与工程科学学报》2015年第2期259-272,共14页Journal of Basic Science and Engineering

基　　金：国家自然科学基金项目(51109071)

摘　　要：针对混凝土坝工程建设投资大、周期长,同时混凝土容易开裂的特点,提出了混凝土坝厚浇筑层、短间歇期的快速浇筑新方法,并以陶岔混凝土坝为背景,从温度控制、防裂安全和施工工艺等角度研究了该方法的可行性和实现策略.基于水管冷却大体积混凝土温度和应力高精度仿真计算理论和方法,对快速浇筑条件下坝体的温度与应力特性和裂缝机理进行了深入分析与探讨,剖析应力安全的主要影响因素,在此基础上提出了合理可行的综合温控防裂方法.混凝土坝脱离基础约束区后将浇筑层厚度从3.0m增加至4.5m甚至6.0m,浇筑层间歇期缩短至7d以内,单纯地从温度控制、应力安全和施工工艺等角度分析,是基本可行的,但须采取更加严格的温控措施.研究表明,浇筑层厚越大,早期坝体内部最高温度越高,仓面及坝体表面温度梯度越大;间歇期缩短,坝体内部最高温度增加,但仓面温度梯度减小,坝体表面温度梯度增加,拉应力与温度梯度呈正相关关系.新方法能够在确保坝体应力安全的前提下显著加快混凝土坝建设速度,在混凝土筑坝技术领域应用前景广泛.To solve the problem of the concrete and easy cracking, a new construction dam construction with large investment, long period technology and cracking prevention method was , so-called concrete thick layers and short time intervals fast pouring method.Based on Taocha concrete dam, the feasibility and implementation strategy were studied from different angles ,such as temperature control ,stress safety and construction technology.The basic theories of temperature field and stress field of concrete and 3D FEM combining with high precision cooling pipe discrete model are used to carry out the study of temperature and thermal stress properties and cracking mechanism under fast pouring method. The major factors affecting the stress safety and the reasonable method for prevention from the cracking were proposed and emphatically discussed. From the temperature control and stress safety point of view, it was feasible that the thickness of layers increased from 3.0m to 4.5m or even to 6.0m, and the intermittent period was shortened within 7d.The numerical results showed that, the greater the layer＇s thickness, the higher the temperature of the dam, and the larger the temperature gradient of dam surface and intermittent surface. The shorter the intermittent period, the higher the temperature of the dam, the lower the temperature gradient of intermittent surface, the larger the temperature gradient of the dam surface. There is a positive correlation between the thermal stress and the temperature gradient.The fast pouring method not only ensure the stress safety of the dam, but also significantly speed up the progress of the dam construction, and has broad application prospects in the field of high concrete dam construction.

关 键 词：混凝土坝 快速浇筑方法 温度 应力 温控防裂 全过程仿真计算 

分 类 号：TV642[水利工程—水利水电工程]