粗粒料颗粒破碎三轴试验研究

Particle breakage of coarse-grained materials in triaxial tests

随着粗粒料在高土石坝等工程中广泛应用,颗粒破碎逐渐成为粗粒料工程特性研究的一个重要方面。通过三轴颗粒破碎试验,研究了某粗粒料等压固结、峰值以及不同应力水平下的颗粒破碎规律,分析了干湿状态的影响。结果表明:等压固结颗粒破碎率与围压之间以及峰值内摩擦角与颗粒破碎率之间均呈幂函数关系;相同围压下颗粒破碎率随应力水平增加而加速增加;相同应力水平下颗粒破碎率随围压增加而增加;不同围压下的颗粒破碎率与应力水平之间可进行归一化处理;同应力状态下湿态颗粒破碎率较干态大,二者差异的决定因素为材料软化系数。同时,对以上结论进行了理论分析,提出了一个颗粒破碎的估算方法,探讨了干湿状态对颗粒破碎影响与材料软化系数之间关系。

With the widespread use in practical engineering projects （such as high earth-rock dams）, the particle breakage becomes an important aspect in studies on coarse-grained materials. Through the triaxial tests of the coarse-grained material, the particle breakage under the isotropic consolidation, peak strength and different stress level conditions are studied. The influences of drying and wetting on particle breakage are analyzed. It is indicated that the power function is fit for the relation between the particle breakage ratio and the confining pressure under the isotropic consolidation, and is also fit for the relation between peak internal friction angle and the corresponding particle breakage ratio; the particle breakage ratio will speed up to increase with the increase of stress level under a certain confining pressure, and increase with the increase of confining pressure under a certain stress level; the relation between the particle breakage ratio and the stress level may be unitary under different confining pressures; with the same stress state, the particle breakage under wet state will be larger than that under dry state, and the difference is mainly determined by softening coefficient of material. At the same time, the theoretical analysis is done for these results, a new method to estimate the particle breakage value is proposed, and the relation between the influence on breakage of dry and wet states and the material softening coefficient is also discussed.