Abstract

Investigating analytical solutions to determine stresses for mine stopes with inclined walls is essential for the design of stopes in the mining industry, contributing to the prevention of serious accidents. Two variables in the analytical formula used for computing the vertical stresses in mine stopes with inclined walls play a vital role in the design. The two variables are the coefficient of lateral earth pressure, K_α, and the ratio η. Here, K_α is the ratio of the normal earth pressure on the inclined wall at some level to the vertical stress at the same point and η is the ratio of the normal lateral earth pressure on the hanging wall to the normal lateral earth pressure on the footwall. The difficulty of using the analytical formula is to choose the correct values of both parameters. Hence, calibrating the formula involves selecting appropriate values of K_α and η in order to predict the actual results of the vertical stress, and consequently provide the designer with appropriate values that can be used in the design of mine stopes with inclined walls. Accordingly, in this study, the coefficient of lateral earth pressure in inclined mine stopes is numerically evaluated for various backfill friction angles; 30°, 35° and 40° with and without reference to the surrounding rock. The ratio η is also investigated at different depths ranging from 25 to 275 m. Moreover, K_α was formulated as a function of the ratio of the height to the breadth for different angles of the inclined stope, i.e., 60°, 70° and 80°. The considered cases in this analysis differ considerably from the commonly considered case in previous research, which completely overlooks the wall inclination effect. Furthermore, the considered cases better represent the actual in-situ conditions because they model the interaction between the sidewalls and the backfilling in the stope. The results have shown that the use of η = 0.6–0.8 and K_α ≤ K_a for the different angles of inclination in the analytical formula resulted in vertical stress being compatible with the numerical analysis results.

Article highlights

• Different researchers considered several aspects of mine stopes; however, none of them considered the effect of the stope wall inclination explicitly.

• Choosing appropriate values of the coefficient of lateral earth pressure, K, and the ratio of the normal lateral earth pressure on the hanging wall to the normal lateral pressure on the footwall, η, is crucial to predict the actual vertical stress.

• In this paper the ratio η is investigated at different depths ranging from 25 to 275 m. Moreover, K was formulated as a function of the ratio of the height to the breadth for different angles of the inclined stope.

中文翻译：

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倾斜采场侧向土压力系数数值分析

摘要

研究分析解决方案以确定倾斜壁采场的应力对于采矿业采场的设计至关重要，有助于预防严重事故。用于计算斜壁采场垂直应力的分析公式中的两个变量在设计中起着至关重要的作用。的两个变量是侧向土压力，系数ķ _α，和比η。式中，K _α为某水平斜壁上法向土压力与同一点竖向应力之比，η是上墙的法向侧向土压力与下墙的法向侧向土压力的比值。使用解析公式的难点在于选择两个参数的正确值。因此，校准公式涉及选择适当的 K _α和 η值，以预测垂直应力的实际结果，从而为设计人员提供适当的值，可用于具有斜壁的采场设计。因此，在本研究中，针对不同回填摩擦角对倾斜采场侧向土压力系数进行了数值评估；30°、35° 和 40° 参考和不参考围岩。比η还对25至275 m范围内的不同深度进行了研究。此外，K _α被公式化为倾斜采场不同角度（即60°、70°和80°）的高度与宽度之比的函数。本次分析中考虑的情况与之前研究中普遍考虑的情况有很大不同，后者完全忽略了壁倾角效应。此外，所考虑的案例更好地代表了实际的现场条件，因为它们模拟了采场中侧壁和回填物之间的相互作用。结果表明，使用η  = 0.6-0.8和ķ _α  ≤  ķ_一个 由于解析公式中不同的倾角导致竖向应力与数值分析结果一致。

文章亮点

• 不同的研究人员考虑了矿场的几个方面。然而，他们都没有明确考虑采场壁倾斜的影响。

• 选择合适的侧向土压力系数K以及上墙法向侧向土压力与下盘法向侧向压力的比值η对预测实际竖向应力至关重要。

• 在本文中，在 25 至 275 m 的不同深度研究了比率η。此外，K被公式化为倾斜采场不同角度的高度与宽度之比的函数。