紫坪铺面板坝堆石料颗粒破碎试验研究

Experimental study of particle breakage of Zipingpu rockfill material

采用大型三轴仪对紫坪铺面板坝堆石料进行了单调和循环荷载下的固结排水剪切试验,研究了不同孔隙比情况下颗粒破碎及剪胀的变化规律。试验表明:(1)单调和循环荷载条件下,堆石料颗粒破碎率与塑性功之间存在一致的双曲线关系;(2)峰值应力处剪胀率与颗粒破碎率在半对数坐标中呈近似线性关系;(3)峰值应力处主应力比与相应的剪胀率呈近似线性关系,且上述结果受初始孔隙比的影响不大。研究成果有助于进一步了解堆石料的颗粒破碎特点,对建立复杂应力条件下考虑颗粒破碎和状态相关性的弹塑性本构模型,分析紫坪铺面板堆石坝汶川地震破损机制是十分有益的。

A series of large-scale consolidated drained triaxial tests were conducted to research particle breakage of Zipingpu rockfill material under monotonic and cyclic loading for different initial void ratios. The results show that there exists a hyperbolic relation between the input plastic work and particle breakage, regardless of the initial void ratio or confining pressure under both monotonic and cyclic loading. The dilatancy factor at peak decreases with the increasing of particle breakage and there exists a nearly linear relation between particle breakage at peak and the dilatancy factor at peak on semilog coordinate, irrespective of initial void ratio. Test results in this study also indicate that there exists an approximate linear relation between peak principal stress ratio and the dilatancy factor at peak, regardless of the initial void ratio. This study results can provide useful references for state-dependent elastic-plastic constitutive model considering particle breakage and finite element analysis of Zipingpu concrete face dam during Wenchuan earthquake; and help to further understand the particle breakage of rockfill materials.