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首页> 外文期刊>Journal Of The South African Institute Of Mining & Metallurgy >Review of coal pillar lifespan prediction for the Witbank and Highveld coal seams
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Review of coal pillar lifespan prediction for the Witbank and Highveld coal seams

机译：Witbank和Highveld煤层的煤柱寿命预测综述

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Coal pillars are prone to scaling over time, and are progressively reduced in size and consequently subjected to increased load and reduced strength. The effective factor of safety therefore reduces. Databases of failed and stable pillars cannot, therefore, be regarded as definitive.More than a decade has passed since the first attempt to predict the lifespan of pillars. This paper presents a review based on the new database and pillar strength equations. The methodology for the analysis is based on the fact that pillars scale. The ultimate safety factor (defined as the ratio between strength and load at the time of failure) is derived, followed by an estimate of the rate of pillar scaling, which results in an estimate of the expected time of failure.It is suggested that the predicted lifespan should not be used as an absolute indicator of expected pillar life, but rather as an index - the pillar life index (PLI) - to complement the safety factor and related probability of failure when evaluating pillar stability. A pillar with a predicted lifespan of less than 500 years would be regarded as being in danger of imminent collapse, while a lifespan of at least 1000 years should be required for long-term purposes.The differences between this analysis and that published in 2003 constitute a strong case for regular reviews of all the empirically based stability indicators, namely the safety factor, probability of failure, and the PLI. Reviews at 10 year intervals appear to be required.The constants in the proposed method are valid only for the Witbank No. 1,2 and 4 seams and the Highveld No. 2 and 4 seams.
机译：煤柱容易随着时间的推移缩放，并且尺寸逐渐减小，因此受到增加的负荷和降低的强度。因此，安全的有效因素减少了。因此，失败和稳定的柱子的数据库不能被视为明确。自第一次尝试预测支柱的寿命以来，超过了十年。本文介绍了基于新数据库和柱强度方程的综述。分析方法基于支柱规模的事实。推导出最终的安全系数（定义为失败时的强度和负载之间的比率），然后估计柱缩放的速率，这导致估计预期的失败时间。这是建议的预测的寿命不应作为预期支柱寿命的绝对指标，而是作为指数 - 柱寿命指数（PLI） - 在评估柱稳定性时补充失败的安全因子和相关概率。预测寿命不到500年的柱子将被视为处于迫在眉睫的崩溃的危险，而长期目的应该需要至少1000年的寿命。此分析与2003年出版的差异构成强大的案例，常规审查所有基于经验的稳定性指标，即安全因子，失败概率和PLI。似乎有10年的评论似乎是必要的。所提出的方法中的常数仅适用于Witbank No.1,2和4个接缝和高款号2和4个接缝。

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