石膏颗粒材料的破碎演化规律

为分析石膏颗粒材料在荷载作用下破碎的分形演化规律,对其进行了等围压、等平均主应力和各向等压固结3种应力路径下的三轴试验,并通过筛分法对试验后石膏颗粒材料的粒径分布进行了分析。试验结果表明,石膏颗粒材料在荷载作用下的破碎程度随初始围压的增大而增大,初始为分形分布的石膏颗粒材料在受荷破碎后,其粒径分布亦具有分形特征。表征粒径分布的分维值与围压和平均主应力之间均呈良好的双曲线关系,分维值渐近值约为2.5。分维值与相对颗粒破碎指数存在显著的线性关系,可作为表征颗粒破碎程度的指标。

Evolution Laws of Breakage for Gypsum Granular Materials

To study the fractal evolution laws of particle breakage for gypsum granular materials under loading, three kinds of stress path tests were conducted with the triaxial apparatus. The stress path included the constant confining pressure, constant mean principal stress and isotropic consolidation pressure. The grain size distributions of gypsum granular materials after tests were analyzed by sieving. It was found that the degree of particle breakage for gypsum granular materials under loading increased with the increase in initial confining pressures. The grain size distributions after breakage present the fractal. The relationship between the fractal dimension of grain size distribution and the confining pressure/mean principal stress can be simulated by hyperbolic curves. The asymptotic value of the fractal dimension is about 2.5. The fractal dimension increases linearly with the increase in the relative particle breakage, and it can also be referred to as a parameter describing the degree of particle breakage for granular materials.