During the multiseam mining process, the overlying strata were damaged due to different mining disturbances, where a large number of fractures were produced which were the main seepage paths of gas and water, easy to cause gas or water inrush accidents. Thus, it is necessary to explore the development characteristics of the fractured zone in the overlying strata from multiseam mining. In this paper, laboratory triaxial compression tests were firstly conducted on the rock specimens subjected to different mining disturbances. In these tests, the specimen was loaded to different stress before a regular test to simulate the different damage effects on the rock strata caused by different mining disturbances. And the corresponding values of m and s could be obtained through a calculation based on the test results. Subsequently, the numerical simulation was conducted to simulate the field situation, in which the m and s values were used in the numerical model combined with the Hoek‐Brown–modified criterion, and the results show that the overburden failure height was increased with the mining disturbances from 48 to 120 m, and then, the effects of mining height and interval thickness on the development height of fracture zone were studied by numerical simulation. Finally, the leakage of roof drilling at different stages was tested and calculated in the field. The results showed that the loss of leakage drilling can directly reflect the development degree of roof cracks, and the detection results were close to the development height of the numerical simulation fracture zone. It is verified that the simulation method used in this paper is feasible and can be used as a reference for similar research.

中文翻译：

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多煤层开采覆岩裂缝带发育特征与现场探测-以案例研究为例

在多煤层开采过程中，上覆地层由于不同的开采扰动而受到破坏，产生了大量的裂缝，这些裂缝是瓦斯和水的主要渗流路径，容易引起瓦斯或水的突击事故。因此，有必要探讨多煤层开采上覆地层裂缝带的发育特征。本文首先对遭受不同采矿干扰的岩石标本进行了实验室三轴压缩试验。在这些测试中，在进行常规测试之前，将试样加载到不同的应力下，以模拟由不同的采矿干扰对岩石地层造成的不同破坏效果。以及m和s的对应值可以通过基于测试结果的计算来获得。随后，进行了数值模拟以模拟现场情况，其中m和s数值模型与Hoek-Brown修正准则结合使用，结果表明，覆岩破坏高度随采矿扰动从48 m增加到120 m，然后，开采高度和层间厚度对采矿破坏的影响通过数值模拟研究了裂缝带的发育高度。最后，在现场测试和计算了不同阶段的屋面钻探泄漏量。结果表明，漏钻损失可直接反映屋面裂缝的发展程度，检测结果与数值模拟断裂带的发展高度相近。验证了本文所采用的仿真方法是可行的，可为类似研究提供参考。