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

Abstract

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.