高土石坝的应力与变形
Stress and deformation of high earth and rock-fill dams
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摘要: 介绍了笔者近年来在影响土石坝应力变形计算的3个主要方面所做的工作:①剖析了邓肯E–ν和E–B模型的差异、对计算的影响、原因和适用条件,通过真三轴仪试验揭示土各向异性的一些规律,提出柔度矩阵性质来反映这些规律;②认为堆石体长期变形计算中应考虑晴雨引起的干湿循环作用,它可作为流变变形的一部分,提出了相应试验方法和计算方法;③提出两种心墙水力劈裂分析方法,一是有效应力与总应力相结合的方法,作施工期心墙的非饱和土简化固结计算,将孔隙水和气作为混合流体来建立固结方程,得出心墙的有效应力和水压力后叠加得总应力,与墙前水压力比较判别水力劈裂的发生,另一是近似反映施工期固结程度的总应力法,相应的本构模型参数用固结不排水剪试验确定。Abstract: The author’s recent works on the problems which influence computation results of stress and deformation of earth and rock-fill dams significantly are introduced.First,the differences between Duncan’s hyperbolic E-ν model and E-B model,the influences of the differences on computed results and their application conditions are analyzed.And the properties of the softness matrix of soils are proposed on the basis of the true triaxial tests.Secondly,the long-term deformation affected by cycling rainfall is studied.It can be taken as part of the rheological deformation.The tests and computing methods are proposed.Thirdly,two analytic methods of hydraulic fracture are proposed.One is to combine the effective method and the total stress method.The simplified computation of consolidation of unsaturated soil is performed,in which the pore water and air are taken as a mixed fluid to set up the consolidation equation.The total stress is the sum of the calculated effective stress and the pore water pressure.The hydraulic fracture is judged by comparing the total stress with the water pressure before the core wall.The other method is the total stress method which can approximately reflect the consolidation to a greater or lesser extent during the construction period.The corresponding parameters of constitutive models are determined based on the consolidated undrained tests.