Intensive mining activity has highlighted the need to study the dynamics of rock mass elements and to assess the degree of their nonequilibrium. The roof, floor, pillars, gateways, and so on are in a highly nonequilibrium state due to difficult mining conditions and high face advance rates. A good tool for predicting the mechanical behavior of the rock mass during mining is mathematical modeling, which is based on the solution of dynamic problems taking into account the nonequilibrium and nonstationary deformation and failure of rocks. In this paper, dynamic modeling has been performed within an evolutionary framework to investigate the steps of first caving in a model rock mass during face advance. All other things being equal, the thickness of the main coal seam roof is varied in the calculations. The steps of first caving are evaluated in the conditions of highly nonstationary deformation of the rock mass. The fluctuation statistics of the stress-strain parameters of the rock mass is analyzed. It is shown that the first roof caving is preceded by a fall in the slope of the amplitude-frequency curve of stress fluctuation.

中文翻译：

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矿井口周围岩体应力-应变演化的数学模型。不同主顶板厚度下第一次放顶的步骤评价

密集的采矿活动突出了研究岩体元素动力学和评估其非平衡程度的必要性。由于困难的开采条件和较高的工作面推进率，顶板、底板、柱子、通道等处于高度非平衡状态。预测开采过程中岩体力学行为的一个很好的工具是数学建模，它基于动态问题的求解，考虑了岩石的非平衡和非平稳变形和破坏。在本文中，在演化框架内进行了动态建模，以研究工作面推进过程中模型岩体中首次崩落的步骤。在所有其他条件相同的情况下，主煤层顶板的厚度在计算中是不同的。在岩体高度非平稳变形的条件下对第一次崩落的步骤进行了评估。分析了岩体应力应变参数的波动统计。结果表明，在第一次顶板崩落之前，应力波动的幅频曲线斜率下降。