中文摘要：

利用自行研制的尾矿细微观力学与形变观测试验装置,研究受载尾矿细观结构变形演化的非线性特征,包括尾矿内部应力的方向性、孔隙比的变化规律、细观孔隙结构的分形特征,以及荷载作用下孔隙结构变形演变规律等。研究结果表明：（1）随着荷载的增加,尾矿试样内不同位置的垂直应力呈阶梯状增加,且略低于荷载,水平应力呈近线性增加,但增量微小,尾矿内部应力存在显著的方向性特征;（2）受荷载作用,尾矿的孔隙比变化较大,随着荷载的增加,试样中不同高度的孔隙比呈非均匀减小,下层的变化滞后于上层,并有趋于一致的趋势;（3）提出尾矿细观结构切面孔隙比的概念,对于同一切面,随着荷载的增加,切面孔隙比与同层孔隙比呈线性正相关;（4）尾矿细观孔隙结构具有显著的周长–面积分形特征,分形维数为1.424～1.537,其值与切面孔隙比存在显著的对数负相关关系;（5）在荷载不变的情况下,随着加载时间的增长,切面孔隙比降低,且有微小的反弹上升现象,而孔隙周长–面积分形维数呈阶段性增加,每一阶段有小幅回落现象。提出的表征尾矿细观结构特征的切面孔隙比与孔隙周长–面积分形维数2个参数,对定量研究尾矿坝体细观结构特征及其力学特性具有重要的实际意义。

英文摘要：

A self-made observation testing apparatus of micro-and meso-scopic mechanics and deformation of tailings is used to study the nonlinear characteristics of deformation evolution for meso-scopic structure of tailings under loading,including directionality of internal stress,variation rule of void ratio,fractal characteristics of meso-scopic pore structure,deformation evolution rule of pore structure under loading,etc.The results show as follows：（1） The internal stress of tailing specimen has obvious direction characteristics,because the vertical stress which is slightly lower than load increases nonlinearly and horizontal stress which is far lower than load increases linearly with the increase in load.（2） The void ratio of tailings,which changes a lot,decreases nonlinearly in different layers.The change in void ratio for lower layer lags behind that for upper layer;and both will finally reduce to the same value.（3） The concept of section void ratio of meso-scopic structure of tailings is put forward.For the same section,the section void ratio has linearly positive correlation with void ratio of the same layer.（4） The meso-scopic structure of tailings has obvious perimeter-area fractal characteristics.The fractal dimensions are 1.424–1.537;and its value has logarithmically negative correlation with section void ratio obviously.（5） The section void ratio decreases under the effect of loading despite tiny rebound,the fractal dimension of perimeter-area increases at stages under the effect of loading,followed by small amplitude reduction at each stage.The section void ratio and fractal dimension of perimeter-area describing the characteristics of meso-scopic structure of tailings are put forward,which is very important to quantitatively study meso-scopic structure characteristics and mechanical properties of tailings dams.