粗粒料强度准则与排土场稳定性研究

排土场稳定性主要取决于排土场的坡角及排弃废石的内部强度。通过低压到高压的三轴压缩试验研究了千枚岩粗颗粒散体材料强度的特性及压力对其强度的影响。试验表明:粗颗粒材料的破碎率随着压力的增大而增加,而增加速率则随着压力的增大而减小,并给出了一个用于描述压力及破碎率的关系式。提出了考虑破碎对强度影响的强度准则,该准则能描述粗颗粒材料的强度随压力的变化情况。采用该强度准则分析排土场的稳定性,其结果更加接近实际情况。而采用摩尔-库仑强度准则计算得到的排土场稳定性安全系数偏大,存在安全隐患。建议采用本文提出的强度准则分析排土场稳定性,特别是对于超高排土场的稳定性分析,更加适用该强度准则。

Investigation on strength criterion of coarse grained material and stability analysis of waste dump

The slope stability of waste dumps is controlled by the slope angle of waste dump and the shear strength of mining wastes. Triaxial tests are conducted to investigate the shear strength of a phyllite coarse grained material from a waste dump. The behavior of the coarse grained material is investigated from low to high confining pressures. Particle breakage of the coarse grained material increases with confining pressure. The increasing rate decreases as the confining pressure increases. An empirical equation is proposed to describe the relation between pressure and breakage rate. A new empirical strength criterion is proposed that can describe the strength change with confining pressure and particle breakage. The slope stability of waste dump is analyzed using the proposed strength criterion. The result is closer to the actual condition. But the safty factor of waste dump calculated by Mohr-Coulomb criterion is relatively large and has potential risk. The slope stability analysis of the waste dump indicates that the proposed strength criterion is reasonable for describing the strength of coarse grained materials from low to high confining pressures. It is strongly recommended that the present strength criterion should be used to analyze the slope stability of high waste dumps.