| Due to its unique advantages,earth-rock dams will take more consideration of earth-rock dams in the construction of high dams.With the maturity of engineering technology,the construction of high earth-rock dams has developed rapidly since the 1980 s.Several 300 m high dams in China have already been under construction or design.These high dams put forward higher requirements for design.The stress arch effect of the earth-rock dam core wall is mainly due to the lower deformation modulus of the core wall than that of the dam shell,large settlement of the core wall,small settlement of the dam shell,and partial self-weight transfer of the heart wall to the dam shell,so that the internal stress of the core wall is reduced,and the dam Shell stress increases.As a result of the arch effect,the vertical stress in the core wall will be reduced,which may lead to cracks in the core wall,which may lead to hydraulic fracturing in severe cases.In-depth study of the arch effect of high-core rockfill dams,ascertaining its arch effect characteristics and the impact of each factor on the arch effect,and then can in-depth study of the heart wall against hydraulic fracturing,the design,construction,and operation of future high earth-rock dams.Provide reference.Studying the arch effect of high earth-rock dams is of great significance to the stability and safety of the dam body.In this paper,the Duncan-Chang model is chosen as a constitutive model to study the arch effect of the heart wall.In this paper,by using the secondary development function of ANSYS,the Duncan Zhang constitutive model was successfully introduced into ANSYS,and the numerical simulation of the dam filling process was realized.The stress distribution and arch effect of the dam before and after the impoundment of the Pubugou gravel-earth core dam are analyzed.The stress distribution law of the dam body when the Poisson's ratio and the internal friction angle of the core soil are changed are studied.The influence of the arch effect of the heart wall is also quantified by the arch effect coefficient ?? to quantify the influence of these two main parameters on the arch effect of the heart wall.(1)In general,the lower arch effect in the heart wall is stronger.The arch effect is the weakest in the middle of the same elevation,and the downstream arch effect is slightly stronger than in the downstream.The arch effect of the heart wall after impoundment also has the above characteristics;The effect is bigger than before the impoundment,and the arching effect is more intense in the middle and lower parts of the heart wall.(2)After analyzing the arch effects of the core-wall soil Poisson's ratio ?=0.3,0.35,and 0.4,it is concluded that the larger the Poisson's ratio of the soil,the greater the arch effect coefficient of the core wall,ie,the arch effect.The weaker.Therefore,when constructing corewall rockfill dams,we should try our best to choose large dam materials with Poisson's ratio,which will help reduce the arch effect of the heart wall.(3)By analyzing the arch effect coefficients of different inner friction angle cores,it can be concluded that the larger the internal friction angle,the smaller the arch effect coefficient of the core wall and the more obvious the arch effect.Therefore,high rockfill dams should follow the principle of large Poisson's ratio and small internal friction angle in the selection of core wall materials.(4)Based on the analysis of the dams with different cohesive forces of the heart wall,it is found that the cohesion of the core wall has no effect on the stress deformation and arching of the dam. |
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