宽级配废石的高排土场稳定性研究

Stability analysis of high dump with wide graded waste rock

宽级配废石的一坡到底的高台阶排土场具有明显的粒径分级特征,传统稳定性分析方法将其简化为多层各向同性的均质土体,却实质性忽略了排土场粗粒土各粒组分布的不均匀性和随机性,导致难以获得其边坡稳定性的合理结论。依托江西某铜矿高台阶排土场,借助自编元胞自动机程序EPOHHM,采用5组窄级配粗粒土表征了高台阶排土场的粒径分级现象,模拟了各粒组散体分布的不均匀性和随机性,分析了不同工况下排土场的位移场及塑性状态,系统地探讨了不同堆排模式下排土场边坡的安全稳定性,提出了一种宽级配废石的高台阶排土场稳定性的精细化分析方法。研究结果表明,排土场发生"拉-剪"破坏;土体中上部有圆弧形滑坡趋势,下部变形表现为沉降,顶部平台产生拉剪裂缝。仅考虑散体力学强度时,底部粗颗粒(d>100 mm)含量的增加对排土场起显著的稳固作用,"单台阶全段高"的堆排模式比"全覆盖式多台阶"更有利于宽级配废石的高排土场安全稳定。研究成果将为保证明显粒径分级的排土场的长期安全稳定提供指导,也为今后分析此类工程问题提供借鉴。

The high-bench dump of wide-graded waste rock formed by slope-to-the-bottom has obvious particle size grading characteristics.Traditional stability analysis methods usually simplify it to multi-layer isotropic homogeneous soil,and substantially ignore the uneven and random distribution of each particle group in the dump.This makes it difficult to obtain a reasonable conclusion about the slope stability.Relying on the high-bench dumping site of a copper mine in Jiangxi,with the help of self-edited cellular automata program EPOHHM,five groups of narrow-graded coarse-grained soils are used to characterize the particle size grading phenomenon of high-bench dump,and to simulate the non-uniformity and randomness of the granular media material in each particle group.The displacement field and plastic state of the dump site under different working conditions are analyzed,and the safety and stability of the dump site slope under different dumping modes are systematically discussed.A detailed analysis method for the stability of a high-step dump with wide-graded waste rock is proposed.The research results show that the"tension-shear"failure occurs in the dump;the middle-upper part of the soil has an arc-shaped landslide trend,the deformation of the lower part manifests as settlement,and the top platform produces tensile and shear cracks.Considering only the mechanical strength of the granular media material,increasing the content of coarse particles(d>100 mm)at the bottom plays a significant role in stabilizing the dump.The"full section height dump of single-step"dumping mode is more conducive to the safety and stability of the high-bench dump with wide graded waste rock than"full overlay dump of multi-step".The research results will provide guidance for ensuring the long-term safety and stability of the dump with obvious particle size grading,and also provide a reference for the future analysis of similar engineering problems.