Sliding Stability Assessment of Concrete Dams Using a 3D Discontinuum Hydromechanical Model Following a Discrete Crack Approach

Abstract

Evaluation of the sliding stability of concrete dams requires the use of numerical tools not only able to simulate the coupled hydromechanical behavior but also able to adequately represent the foundation discontinuities and the specific features of dam foundations. The formulation of a three-dimensional (3D) small displacement finite element model based on interface elements to simulate the discontinuities is presented. In this model, the hydraulic behavior is simulated assuming that the water flow occurs only along channels located at the edges of the triangular interface elements that simulate the discontinuities. The model is used to perform coupled hydromechanical analysis of a large arch-gravity dam and to assess safety against dam base sliding, assuming different constitutive models at the dam/foundation interface and two different approaches: (i) strength reduction method and (ii) amplification of the hydrostatic pressure, assuming an increase in the reservoir level. The present study shows that consistent results are obtained with the proposed numerical model and that stability analysis should preferably be carried out using the method of increasing the hydrostatic pressure and the corresponding uplift pressures, as this methodology leads to significantly lower safety factors.

Physical Model Tests of Concrete Buttress Dams with Failure Imposed by Hydrostatic Water Pressure

“…Analytical methods have also been developed for assessing the 3D effects on concrete gravity dams [5,22,23]. Stability analyses of entire gravity dams, including their 3D behavior, have been performed using FE simulations [24], but, to the authors' knowledge, the 3D behavior of concrete buttress dams has not been examined. than concrete structures.…”

Analysis of the field studies of the foundation deformations and total draft of the Boguchansk HPP concrete dam

“…При этом критерий К1 соответствует переходу от сжатия контактного шва к растяжению (К1 ≥ 0), а критерий К2 не назначается. Таким образом, на основе анализа данных комплекса натурных наблюдений осуществляется контроль устойчивости бетонной плотины, так как устойчивость обеспечивается при воздействии вертикальных сжимающих напряжений на контакте подошвы плотины с основанием, то есть имеют место вертикальные деформации сжатия (в особенности в верховой части плотины), что также обосновано значительным объемом исследований состояния контакта бетонных плотин со скальными основаниями [7][8][9][10][11][12][13][14][15][16][17].…”