To study the fracture evolution of overlying strata for ascending mining in a short-distance coal seam group, a two-dimensional physical simulation model was designed based on a specific geological condition. The fracture development zone was divided into the compaction zone and active zone by monitoring and analyzing the macro fracture evolution of the surrounding rock mass during the excavation of multiple coal seams. The secondary fracture development process of the overlying strata was demonstrated with a physical model. The quantity, length, and inclination of the fracture were calculated with MATLAB software, and the results were verified by geological radar. The total number of fractures between two coal seams increased with a “parabola” shape during the excavation of the lower coal seam, the crack angle was mainly vertical and horizontal, and the number of horizontal cracks first increased and subsequently decreased; the excavation of the upper coal seam caused the secondary fracture development process of the overlying strata, and the relief range and its extent increased. The mining-induced cracks from the lower and upper coal seams connected with each other, especially the permanent vertical fracture in the cutting room side and face side. Finally, the three-dimensional gas fissure was formed.

中文翻译：

---

基于MATLAB分析和地质雷达的物理模型中多煤层开采上覆地层的断裂模式

为研究短距离煤层群上行开采上覆地层裂缝演化，基于特定地质条件设计二维物理模拟模型。通过对多煤层开挖过程中围岩宏观裂缝演化的监测分析，将裂缝发育带划分为压实带和活动带。用物理模型论证了上覆地层次生裂缝发育过程。利用MATLAB软件计算裂缝的数量、长度和倾角，并通过地质雷达对结果进行验证。下煤层开挖过程中，两煤层间的裂缝总数呈“抛物线”状增加，裂缝角度以纵横为主，横向裂纹数量先增加后减少；上煤层的开挖引起上覆地层次生裂缝发育过程，地层起伏扩大。上下煤层的采动裂缝相互连接，尤其是采掘室侧、工作面侧的永久竖向裂缝。最终形成了三维气隙。特别是切割室侧面和正面的永久性垂直断裂。最终形成了三维气隙。特别是切割室侧面和正面的永久性垂直断裂。最终形成了三维气隙。