复杂条件下特高土石坝建设与长期安全保障关键技术研究进展

Research progresses in key technologies for construction and longterm safety protection of extra high earth-rock dams under complicated conditions

我国是世界上200 m以上特高土石坝数量最多的国家,复杂建坝条件和运行环境给这些高坝大库的建设和长期安全保障带来了严峻挑战.本文介绍了近年来我国在复杂条件下特高土石坝建设与长期安全保障关键技术等领域的主要研究进展:揭示了筑坝粗颗粒土石料力学特性的尺度效应、细观及劣化机理,建立了可考虑加载与流变耦合效应的堆石体流变计算模型;基于计算接触力学方法提出了高土石坝复杂接触系统数值模拟方法,并运用于面板坝面板损伤和心墙坝坝内廊道破损机理研究;研发了变形与渗流耦合的试验装置,进行了防渗土料渗透特性、坝体和坝基防渗系统服役性能试验;基于当量密度法提出了覆盖层密度的旁压试验方法,并进行了相关现场试验;研究提出了300 m级特高面板坝复式结构、坝体增模技术及面板设计方法;依托大石峡工程提出了特高面板砂砾石坝的安全评价和控制标准.上述研究成果已为如美心墙堆石坝、大石峡面板砂砾石坝等特高土石坝工程设计和优化等提供了重要的科技支撑.

China has the largest amount of extra-high earth-rock dams over 200 m in the world. Complicated construction and severe operation conditions pose great difficulties and huge challenges in their construction and long-term safety. This paper introduces main research progresses in the areas of Key Technologies for Construction and Long-term Safety Protection of Extra High Earth-rock Dams under Complex Conditions. The particle-size effect, mesoscopic and deterioration mechanism of dam materials were studied throughly. The calculation model of rheological behavior of rockfill materials considering loading and creep coupling effect was established. The numerical simulation method for complex contacting problems in high earth-rock dams was developed using computational contact mechanics, and was used in studying the damage mechanism of concrete slabs and galleries. Testing apparatus conducting deformation-seepage coupling experiments were fabricated, and were used to investigate the permeability characteristics of core materials, the performance of anti-seepage systems in dam body and foundation. An equivalent density method was proposed to evaluate the in-situ density of overburden materials based on pressuremeter tests both in laboratory and field. New compound structure, modulus increasing technology, slab design method and water-stop materials for extra-high concrete face rockfill dams were studied, and safety evaluation and control standards were proposed for the demonstrating Dashixia project. The relevant results have provided technological supports for the two demonstrating projects, i.e. Rumei and Dashixia extra-high earth-rock dams,improving considerably the construction level and long-term safety of extra-high earth-rock dams.