珊瑚砂大剪切应变下的剪切特性和分形维数

利用Wille Geotechnik环向剪切仪对3种不同粒径的珊瑚砂进行了大剪切位移的环向剪切试验，探讨了颗粒破碎对珊瑚砂强度和残余应变发展的影响。试验结果表明：颗粒破碎随着剪切位移的增加逐渐增加，且初始粒径较大的均匀级配珊瑚砂粒径越大颗粒破碎越多。颗粒破碎对峰值强度和残余强度无影响，但对珊瑚砂的体积应变有显著影响，颗粒破碎较多的试样其体积应变也较大。建立了考虑长宽比、球形度和凹凸度的分形维数计算公式。由于颗粒破碎后颗粒形状在全粒径范围内的自相似性和无尺度性，考虑颗粒形状与不考虑颗粒形状的公式计算得到的珊瑚砂分形维数基本一致。

Shear behaviors and fractal dimensions of carol sand at large shear strains

Wille Geotechnik ring shear apparatus was applied to conduct large shear strain ring shear tests on three samples of uniform carol sand with different sizes. This paper investigates the effects of particle breakage on peak strength and residual strength. The experimental results indicate that particle breakage increases with increasing the shear distance, and also increases with increasing particle size. Particle breakage has subtle or negligible effect on the peak strength and residual strength. However, particle breakage remarkably influences the volumetric strain, where the volumetric strain increases with increasing the particle size because of large particles suffered greater particle breakage. An equation for fractal dimension considering length-width ratio, sophericity and camber is established. As the self-similar and no scale of particle along with ranges of sizes, the fractal dimension calculated through the cumulative number of particles with consideration of particle shape is the same with that of particles without considering of particle shape.