Theoretical unloading fracture mechanism and stability analysis of the slope rock masses in open-pit mines

IF 4.5 3区地球科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Geomatics Natural Hazards & Risk Pub Date : 2023-11-01 DOI:10.1080/19475705.2023.2274810

Jianming Wang, Zihan Zhou, Wei Dou, Zhonghui Chen

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Abstract

Instability of the rock slopes in open pit mines during the excavation unloading is an increasingly serious problem in the field of slope engineering. To explain the mechanical mechanism of slope unloading damage from a theoretical point of view, a simplified mechanical model of slope excavation based on the theory of fracture mechanics and the rock strength damage criterion is established. The damage process of the slope under excavation disturbance is dynamically analyzed by combining the interstructural characteristics of the slope. The solution equations for the extent of the plastic zone at the end of the crack of the excavated slope and its propagation length are derived. Calculation method of unloaded slope stability coefficient is proposed based on the mechanical model of crack propagation. The results show that (1) the stress intensity factor (SIF) at crack end in the slope under the action of unloading was larger than that under the original condition. (2) The range of the plastic zone at crack end in the slope rock mass can be attributed to the slope height, inverse logarithmic function to the slope angle, positive proportional function to the crack length, and the periodic fluctuation function of the crack angle. (3) The slope safety factor (SF) was found to be negatively related with the slope angle, slope height, crack angle, and the crack length unloading factor and positively related with the friction factor. Finally, the reasonableness of the theoretical derivation is verified by an engineering case study.

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露天矿边坡岩体卸荷破裂机理及稳定性分析

露天矿山岩质边坡在开挖卸载过程中的失稳问题是边坡工程领域日益严重的问题。为了从理论角度解释边坡卸荷损伤的力学机理，基于断裂力学理论和岩石强度损伤准则，建立了边坡开挖的简化力学模型。结合边坡的结构间特性，对边坡在开挖扰动作用下的破坏过程进行了动态分析。导出了开挖边坡裂缝末端塑性区范围及其扩展长度的求解方程。基于裂缝扩展的力学模型，提出了卸载边坡稳定系数的计算方法。结果表明:(1)卸荷作用下边坡裂缝端应力强度因子(SIF)大于原状;(2)边坡岩体裂缝端塑性区范围与边坡高度、边坡角度成反对数函数、裂缝长度成正比例函数、裂缝角度周期波动函数有关。(3)边坡安全系数(SF)与坡角、坡高、裂缝角、裂缝长度卸荷系数呈负相关，与摩擦系数呈正相关。最后，通过工程实例验证了理论推导的合理性。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Geomatics Natural Hazards & Risk GEOSCIENCES, MULTIDISCIPLINARY-METEOROLOGY & ATMOSPHERIC SCIENCES

CiteScore

7.70

自引率

4.80%

发文量

117

审稿时长

>12 weeks

期刊介绍： The aim of Geomatics, Natural Hazards and Risk is to address new concepts, approaches and case studies using geospatial and remote sensing techniques to study monitoring, mapping, risk mitigation, risk vulnerability and early warning of natural hazards. Geomatics, Natural Hazards and Risk covers the following topics: - Remote sensing techniques - Natural hazards associated with land, ocean, atmosphere, land-ocean-atmosphere coupling and climate change - Emerging problems related to multi-hazard risk assessment, multi-vulnerability risk assessment, risk quantification and the economic aspects of hazards. - Results of findings on major natural hazards