Safety evaluation of rock-filled concrete gravity dam with long section during the impoundment operation period
XU Xiaorong1, HE Taohong2, LEI Zhengqi3, ZHANG Quanyi2, LI Cong4, JIN Feng4
1. School of Water Resources and Hydropower Engineering, North China Electric Power University, Beijing 102206, China; 2. Zunyi Survey and Design Institute of Water Conservancy and Hydropower Co. Ltd, Zunyi 563002, China; 3. China Institute of Water Resources and Hydropower Research, Beijing 100038, China; 4. State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China
Abstract：Rock-filled concrete (RFC) is a dam construction technique that heavily relies on engineering machinery. Because of the conservative design concept, currently, many transverse joints exist in RFC gravity dams, resulting in a narrow working space and a small radius for mechanical rotation. The Dagutai RFC gravity dam innovatively adopts a design with fewer joints, and it has the longest section (134 m) among all RFC gravity dams. The reservoir has been in operation for more than 3 years after its impoundment. To determine the safety state of the Dagutai gravity dam during the impoundment operation period, this paper researched the dam's working behavior under different loads, using dam temperature, seepage pressure, and displacement monitoring results, along with the temperature stress simulation of the finite element method (FEM). The results revealed that the dam body's temperature and seepage pressure are within normal limits, and the dam's longest section has no obvious cracking or seepage, indicating that the dam performed well during storage and operation. RFC's adiabatic temperature rise is low, as evidenced by the temperature rise of the most unfavorable position in the long section being less than 10℃. The section length of the RFC gravity dam can be appropriately extended, but the large lifting surfaces near the foundation should not be constructed during hot seasons, to control the initial temperature and reduce temperature stress during construction. Compared to standard dam sections, the long section's stress state meets the requirements, and the maximum stress can reach 2.5 MPa under empty or full reservoir conditions. Reinforcing mesh and short joints should be installed in the upstream impermeable layer. Overwintering in the upstream surface above water and the downstream surface can cause high tensile stress. If a gravity RFC dam with no joints is built, the large tensile stress at both ends of the dam should be considered. Even when the overloading factor is 10.0, there was no yield failure through the upstream and downstream of the dam, indicating that the overloading safety of the dam is high and the dam stability is good. This paper's research can provide scientific guidance for the structure design of RFC gravity dams in the future.
徐小蓉, 何涛洪, 雷峥琦, 张全意, 黎聪, 金峰. 超长坝段堆石混凝土重力坝蓄水运行安全评价[J]. 清华大学学报（自然科学版）, 2022, 62(9): 1375-1387.
XU Xiaorong, HE Taohong, LEI Zhengqi, ZHANG Quanyi, LI Cong, JIN Feng. Safety evaluation of rock-filled concrete gravity dam with long section during the impoundment operation period. Journal of Tsinghua University(Science and Technology), 2022, 62(9): 1375-1387.
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2022, Vol. 62 
