三种本构沥青混凝土心墙土石坝特性

A comparison of three different models to predict the stress and deformation characteristics of earth-rockfill dam with asphalt concrete core-wall

针对土石坝静力分析中常见的三种本构模型,即Duncan E-μ、Duncan E-B和双屈服面模型是。以沥青混凝土心墙土石坝为研究对象,建立了心墙坝的三维有限元模型,并考虑了沥青混凝土心墙和过渡料、混凝土基础间的接触关系,采用接触单元模拟相互间的变形和应力协调,对心墙和坝体的变形和应力应变特性进行了分析对比。分析结果表明对于坝体应力,三种模型计算结果无论是极值还是分布都比较一致。对坝体和心墙变形,三种模型的沉降量分布是一致的,但Duncan E-μ和E-B模型求得的最大沉降量更接近实际观测值;在心墙应力分析中,双屈服模型的计算结果比较均匀合理。

Duncan E-μ model,Duncan E-B model and the double-yield-surface model are three major constitutive models in the static analysis of earth-rockfill dam.In this paper,an actual asphalt concrete core-wall dam in a hydraulic engineering is employed to compare the three models.The three-dimensional finite element model of the core-wall dam is presented.The contact relations between the core-wall and the transition material and foundation of dam are taken into account using the contact element which can simulate the interdependence of deformation and force.Numerical results show that both the stress extremum and stress distribution of dam body via three different models are coincident one another.In the deformation analysis of dam body and core-wall,it is found that the maximum values of sedimentation via Duncan E-μ model and Duncan E-B model,which are greater than the value via double-yield-surface model,are close to the practical test data though the deformation distribution via three models are in good agreement.The analysis results of core-wall stress via double-yield-surface model are more reasonable than the ones based upon other two models.