模拟月壤颗粒形状特征及其对抗剪强度影响分析

为研究颗粒形状特征对抗剪强度的影响,对模拟月壤颗粒进行体视显微镜扫描拍照,并利用图形处理软件对各粒径组颗粒的形状特征进行量化统计.结果表明:模拟月壤颗粒的主要形状有圆形、类椭圆形、类三角形和类正方形等.利用PFC 3D软件中的"Clump"命令构造出不同形状的模拟月壤颗粒并通过三轴试验数值模型研究其抗剪强度指标值,模拟结果表明:颗粒形状对模拟月壤的抗剪强度指标值有着明显的影响,其中构造出的类椭圆体颗粒试样抗剪强度最大,而规则的球体颗粒试样的抗剪强度最小;当颗粒形状都是类三角体时,凹凸度越大,试样的抗剪强度指标值也越大.

Analysis of Particle Shape Characteristics of Lunar Soil Simulant and Its Effect on Shear Strength

In order to study the effect of particle shape characteristics on shear strength， particles of lunar soil simulant are scanned and photographed with a stereo microscope. Then， a digital imaging processing software is used to statistically analyze the geometric characteristics of the particles. It shows that the particles of lunar soil simulant mainly are of four shapes: sphere， quasi-ellipsoid shape， quasi-trigonal shape and quasi-cube shape. Particles with the three irregular shapes are simulated as clumps in PFC 3D， and the numerical model of tri-axial test is obtained to study their shear strength. The numerical results show that: the particle shape has a noticeable effect on shear strength; the shear strength of particles of quasi-ellipsoid shape is the greatest of all， while the sphere particles has the minimum shear strength. For particles of the same quasi-trigonal shape， the greater ruggedness it is， the stronger shear strength the sample has.