中文摘要：

水工材料的力学特性和细观机理难以用现有的连续体力学理论予以解释,颗粒滑移是影响水工材料强度和变形的一个重要因素。该文以钢珠构成的颗粒材料的室内三轴试验为基础,采用颗粒流方法对其细观力学特性及变形破坏过程开展一系列三轴数值试验研究,初步探讨不破碎散体材料一些细观变形机理。研究结果表明：围压越高,初始模量越大,初始泊松比越小;当摩擦系数大,颗粒刚度比小时,初始模量较大;加载过程中孔隙比随轴向应变的增大而增大,且孔隙比增大的速率随围压的增大而减小;低围压条件下,应力变形曲线呈小幅软化和硬化交替波动的形式。高围压条件下,应力变形曲线表现为以硬化为主要趋势的软化和硬化交替波动的形式;应力～应变曲线的波动主要是由于颗粒间局部咬合结构的破坏和重新调整所至。

英文摘要：

It is difficult to describe the mechanical characteristics and micro mechanism of hydraulic materials with the continuum mechanics;particle sliding is one of the major factors that affect the strength and deformation of these materials.This paper presents a series of numerical triaxial tests based on the physical triaxial tests of steel balls and the particle flow method to explain the mechanical behaviours of uncrushed granular materials.Micro mechanism of deformation on uncrushed materials is discussed preliminarily.The simulations show that an increase in confining pressure causes an increase in initial modulus and a decrease in initial Poisson＇s ratio,and that a greater friction coefficient or a lower stiffness ratio of particle produces a greater initial modulus.The void ratio on loading increases with the axial strain,and its increasing rate is lowered by a higher confining pressure.Under lower confining pressure the deformation-pressure curve takes alternate softening-hardening fluctuations of small amplitudes,while under higher confining pressure the amplitudes become greater with the fluctuations dominated by hardening.Such deformation fluctuations of granular materials should originate primarily from breaking and readjustment of its local bite structures.