粗粒土的颗粒破碎耗能及剪胀方程研究

颗粒破碎对于粗粒土的应力变形性质有显著影响。在Rowe剪胀方程的基础上考虑颗粒破碎耗能的影响，并引入颗粒破碎的演化规律对颗粒破碎耗能进行计算，得到了一个简单实用且对粗粒土适用性较好的剪胀方程。主要结论如下：（1）通过粗粒土的三轴CD试验结果分析并证明了弹性应变对于剪胀比的影响较小，因此，可以将剪胀比 表示为 ，进而得到了剪胀方程表达式的一般形式。（2）将剪胀方程中的临界状态应力比Mc折减为摩擦系数M，并引入了颗粒破碎的演化规律，将M定量表示为广义剪应变的函数，从而使得所计算的破碎耗能在剪切过程中是递增的，且逐渐趋于稳定值，符合了颗粒破碎不可逆的规律。（3）试验表明，剪胀方程中的未知量 与摩擦系数M之间呈现显著的线性关系，将该关系代入剪胀方程即确定了方程的具体表达形式，并且利用堆石料的三轴CD试验证明了其对粗粒土的剪胀性预测效果较好。

Study on the particle breakage energy and dilatancy of coarse-grained soils

Using Rowe’s stress dilatancy equation to considering the influence of particle breakage energy is a main method to express the dilatancy property of coarse-grained soils. However, the calculated breakage energy may be decreased during shearing or even be negative, which violates the irreversible thermodynamic theory. The reason lies in the friction factor, namely the critical state stress ratio Mc, is too larger during the entire shearing process. The breakage energy was closely relate with the evolution of particle breakage. An equation was proposed to express the relationship between the particle breakage factor and stress/strain state. A reduction scheme was suggested to replace the Mc by a new friction factor M. The newly calculated breakage energy proved to increase during shearing and approach to a stable value, which is reasonable and in accordance with the evolution of particle breakage. Then, the remaining unknown parameter dEb/pdεs of the dilatancy equation obtained by consolidated drained triaxial test was found to show a significant linear relationship with M. Therefore, the dilatancy equation was finally determined and verified by a series of test data from different rockfills.