中文摘要：

冰水堆积体是一种典型的混合介质,由软弱＂土＂与坚硬＂石＂构成,其参数选取和分析方法困难。利用数字图像重构方法模拟冰水堆积体结构特征,可反映块石分布特征;以基于图像识别的块石分割和颗粒离散元建模分析方法,研究了堆积体内介质分布、土体颗粒强度对混合介质力学参数的影响规律,分析了冰水堆积体变形、峰值抗剪强度及峰后段抗剪强度的变化规律。结果表明：冰水堆积体混合介质在峰值前的变形曲线呈非线性硬化性,峰后呈现塑性特性,其综合抗剪摩擦角随基质土的黏结强度提高而降低;当块石含量小于25%时,抗剪切强度近似等于基质土强度,块石含量高于25%时,抗剪切强度随块石含量增加而提高;由于受块石空间分布影响,块石含量与摩擦角间的相关性要比其与黏结强度间的高;该成果应用于云南古水水电站坝前冰水堆积体发现,含块石混合介质内摩擦角比纯土高0°～8°,与工程判断较吻合。该方法能弥补室内试验不能考虑大尺寸块石的困难,可作为室内试验获取力学参数方法的有益补充。

英文摘要：

Outwash deposit is one of the typical mixed materials,which is made up of soft soil grains and hard rock mass;and it is very difficult to determine its mechanical parameters and analyze its mechanical characteristics.Digital image reconstruction method is used here to help construct the structure of outwash deposits and to reflect the distribution of stones as well as the feature of clump.So a modeling method with particle discrete element method based on image recognition is built up,by which the laws on mechanical parameters of media distribution,strength of soil particles are researched.Then deformation characteristic,peak strength and shear strength after peak are analyzed.It is shown that the deformation curve before peak strength presents a feature of nonlinear hardening process,while it is like perfect plasticity after peak strength;composite friction angle of mixed material will decrease with the increase of bonding strength;when the stone content is less than 25%,composite shear strength approximately is equal to soil strength;when the stone content is higher than 25%,the shear strength will increase with the increase of stone content.Due to the effect of rock structure,the correlation coefficient between stone content and friction angle is greater than that between stone content and cohesion strength;and it can be concluded that the actual friction angle of geology deposits of Gushui Hydropower station is 0-8 degrees higher which is agreement to engineering conclusion.This method can consider stones of large size,which is a great difficulty in laboratory test,and can be a beneficial method for mechanical test in determining shear strength.