考虑颗粒破碎影响的粗粒土的剪切强度理论

由于粗粒土的粒径相差很大,通过剪切试验测量粗粒土的剪切强度很麻烦,且剪切试验费时费力、试验数据离散性大;另外,已有剪切强度经验公式中的参数没有明确的物理含义,工程应用中难以确定。本文根据颗粒破碎的分形模型,揭示单颗粒破碎强度的尺寸效应,假设剪切强度是颗粒接触面上的摩擦力,导出用正应力幂函数表示的粗粒土剪切强度公式,幂函数的指数是颗粒破碎分维的函数,并采用垃圾炉渣的颗粒破碎分维和剪切强度试验结果进行验证。

Theory of shear strength of granular materials based on particle breakage

Great efforts have been made to determine the shear strength of coarse granular materials using both elaborate laboratory tests and empirical methods. However, the elaborate laboratory tests are difficult and time consuming to perform, and the physical meaning of empirical parameters is not obvious in the empirical methods. A simple method to determine the shear strength of coarse granular materials is proposed based on a fractal model for particle breakage. The shear strength of coarse granular materials can be seen as the friction between particle contacts, and the particle contacts can be modeled by the fractal model for particle breakage. Thus the shear strength of coarse granular materials can be easily estimated using the fractal dimension of particle-size distribution. The shear strength of coarse granular materials obtained from the proposed method is in satisfactory agreement with the experimental data of bottom ash from municipal solid waste incineration (MSWI).