粗粒筑坝材料的动力变形特性

Deformation behaviour of coarse grained materials under cyclic loading

结合室内大型动三轴试验资料,对粗粒料的动力变形特性进行研究后认为,在复杂的高应力条件下振动过程中试验粗粒料由于体积缩小而变得更为密实,其动应力-应变关系与Hardin-Drnevich模型的双曲骨架曲线假定有明显差异,其阻尼特性也不符合Hardin假定;提出了反映试验过程中材料振动硬化特性的幂函数型动应力-应变关系模型和基于试验资料的粗粒料阻尼比估算公式;粗粒料的动残余变形特性与其初始密度、静应力状态、动荷载、振动持续时间等因素密切相关,建立了考虑初始固结围压影响的粗粒料残余应变与动剪应力之间的关系模型。可为强震区超高土石坝的深入研究提供可靠的理论依据。

The dynamic deformation characteristics of coarse grained material are researched by large-scaled indoor triaxial test.The conclusions are that the dynamic stress-strain relationship of coarse granule doesn’t conform to the presumption of hyperbolic skeleton curve of Hardin-Drnevich under the situation of high stress,because of its volume becoming smaller.Therefore,an exponential stress-strain constitutive equation which reflect the vibration hardening of materials is proposed;the damping of coarse granule doesn’t conform to the Hardin presumption;an power function type of equation based on the experimental references is suggested;the seismic residual deformation of coarse granule is greatly associated with the initial density,static stress,dynamic load,duration of vibration and so on;the relationship between residual deformation and dynamic shearing stress of coarse granule is built considering the effect of initial consolidation confining stress.The research basis is provided for the construction of superhigh rockfill dam in meizoseismal areas.