Subjects: Mechanics >> Applied Mechanics submitted time 2023-03-20 Cooperative journals: 《应用力学学报》
Abstract： Based on the field investigation of dam break cases and flume model test , the numerical model ofovertopping break of concrete-face sand-gravel dam (CFSGD) is established to simulate the interaction a-mong water flow characteristics , sand-gravel materials , and concrete face slab. The model is mainly com-posed of three parts : ① Considering the erosion characteristics between the vortex water flow and sand-gravel materials , the RNG k-e turbulence model is introduced to simulate the reverse erosion of the vortexwater flow.2 Through the sediment transport formula and fluid volume method (VOF) traces the inter-face between sand and water erosion , and considers the pore characteristics of sand-gravel materials.3Based on the moment equilibrium method, the failure process of the concrete face slab under its self-weightand water loads is calculated.The numerical model is verified by the flume model test. 'The results showthat the numerical model established in this paper can accurately simulate the reverse erosion of the vortexwater flow on the dam during the failure process and the detailed evolution process of the face slab breach.The relative error between the measured data and the calculated peak breach flow , the development of thebreach of the rockfill body , the duration of the break and the length of the face slabs are all less than15% , which verifies the rationality of the numerical model.Compared with the parametric model , the nu-merical model of dam breach proposed in this paper provides more detailed results.
Subjects: Mechanics >> Solid Mechanics submitted time 2022-12-21 Cooperative journals: 《应用力学学报》
Abstract：
The essential cause of the separation between concrete face and cushion layer is the uncoordinated deformation between concrete face and cushion layer.In order to explore the influence of topographical and geological conditions in the dam site and the cyclic rise-fall of reservoir water level on the separation between concrete face and cushion layer,we use the sub-model method to accurately simulate the mechanical response characteristics of slab void area in this paper,and then explore the sensitivity of width-to-height ratio of valley T,overburden thickness F and cyclic rise-fall times of reservoir water level K on the separation between concrete face and cushion layer based on the relative displacement method.The results show that the characteristic value of separation between concrete face and cushion layer increases logarithmically with the increase of the three.The increase of the width-to-height ratio of valley T weakens the constraint of valley topography on dam body,thus promoting the development of the separation between concrete face and cushion layer.However,when the width-to-height ratio of valley T is greater than 2.0,its sensitivity on separation between concrete face and cushion layer is significantly reduced.The increase of the overburden thickness F promotes the nonuniform settlement of the dam body,and causes the area of separation between concrete face and cushion layer to gradually expand to the bottom.On the other hand,the sensitivity of the separation between concrete face and cushion layer decreases as the thickness of the cover layer increases.At the same time,due to the difference in deformation characteristics between the concrete face and the rockfill,the area of separation between concrete face and cushion layer expands slowly under the action of the cyclic rise-fall of reservoir water level and eventually stabilizes.Among the three,F has the highest sensitivity to the maximum depth of separation of concrete face and T has the highest sensitivity to the downhill length of separation.The research results in this paper can provide the corresponding theoretical basis for the prevention and treatment of separation between concrete face and cushion layer.
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