Mining-induced stresses in underground coal mines play a significant role in pillar and ground support design, hence in the safety of mining operations. In the US, Analysis of Longwall Pillar Stability (ALPS) and in Australia, Analysis of Longwall Tailgate Serviceability (ALTS) software are used for designing Longwall coal mine layouts; and in the US, Analysis of Retreat Mining Pillar Stability (ARMPS) software is used to design retreat room-and-pillar mine layouts. All these software determine the adequacy of the design by comparing the estimated loads to the load-bearing capacity of the pillars and they use the “abutment angle” concept and a square decay stress distribution function to calculate the magnitude and distribution of the mining-induced loads. The abutment angle concept has been successfully applied to US longwall coal mines with the use of ALPS and ALTS in Australia. ARMPS uses the same concept for retreat room and pillar coal mine design in the US. The suggested abutment angle for coal mines in the US was derived as 21° by the back analysis of underground stress measurements from the 1990s and implemented in ALPS and ARMPS. The ALPS methodology was re-examined and calibrated for Australian conditions with additional Australian stress measurements and resulted in the original ALTS methodology which has been continually improved and expanded with additional cases. In this paper, some recent stress measurements are back-analyzed, and the abutment angles are investigated to verify the applicability of using 21° in retreat room and pillar mines with different depths and mining dimensions. For shallow mines, the derivation of the 21° abutment angle is supported by the new case histories. However, at depths greater than 200 m, the abutment angle was found to be decreasing with increasing depth. In this study, a new equation for the calculation of abutment angle for moderate and deep cover cases was constructed and tested for its applicability in retreat room and pillar mines. The differences in the mechanism of complete side abutment loads in shallow and deep cover mines are further analyzed by applying the finite volume modeling (FVM) approach to two case study mines, one shallow, and one deep cover. A 2D model of each mine is created and one-side and two-side abutment loads of consecutive panels are analyzed. Analysis of the deep cover mine indicated that the prior panel gobs provide a considerable amount of support to the overburden strata. These higher gob loads prevent a higher percentage of overburden loads from being transferred to the active panel workings, and this is in agreement with the lower abutment angles observed for deep cover mines. The findings of this study should only be used for retreat room-and-pillar mines’ production pillar loads since these are calculated geometrically using the abutment angle concept.

中文翻译：

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中深隐蔽室及柱式矿井台座角法再分析及有限体积模型加载力学研究

地下煤矿中的采矿应力在支柱和地面支撑设计中起着重要作用，因此对采矿作业的安全性具有重要意义。在美国，长壁支柱稳定性分析 (ALPS) 和澳大利亚，长壁尾门可维修性分析 (ALTS) 软件用于设计长壁煤矿布局；在美国，采用分析后退矿柱稳定性（ARMPS）软件来设计后退房柱矿布局。所有这些软件都通过将估计的载荷与支柱的承载能力进行比较来确定设计的充分性，并使用“邻接角”概念和平方衰减应力分布函数来计算采矿诱导的大小和分布。负载。在澳大利亚，使用 ALPS 和 ALTS 的美国长壁煤矿已成功地应用了桥台角概念。ARMPS 在美国的撤退室和支柱煤矿设计中采用了相同的概念。美国煤矿的建议桥台角是 21°，是通过对 1990 年代地下应力测量结果的反向分析得出的，并在 ALPS 和 ARMPS 中实施。ALPS 方法针对澳大利亚条件进行了重新检查和校准，并进行了额外的澳大利亚压力测量，并产生了原始的 ALTS 方法，该方法随着其他案例不断改进和扩展。本文对近期的一些应力测量进行了反分析，并研究了桥台角度，以验证使用21°在不同深度和开采尺寸的后退室和柱状矿山中的适用性。对于浅矿，21° 桥台角的推导得到了新案例历史的支持。然而，在深度大于 200 m 处，发现邻接角随着深度的增加而减小。在这项研究中，构建了一个新的计算中等和深覆盖情况下的桥台角的公式，并测试了其在后撤室和支柱矿中的适用性。通过将有限体积建模 (FVM) 方法应用于两个案例研究矿山，一个浅层和一个深覆盖层，进一步分析了浅层和深层覆盖矿井中完全侧基台载荷机制的差异。创建每个矿山的 2D 模型，并分析连续面板的一侧和两侧桥台载荷。对深覆盖矿井的分析表明，先前的面板采空区为上覆地层提供了大量的支撑。这些较高的采空区负载阻止了更高百分比的覆盖层负载转移到活动面板工程，这与在深覆盖矿井中观察到的较低桥台角度一致。本研究的结果应仅用于后退房柱式矿山的生产支柱荷载，因为这些荷载是使用桥台角概念进行几何计算的。