A Mechanical Analysis Of Support Instability Risk Along The Strike Of Coalface In Thick Coal Seam With Large Dip Angle: A Case Study

Studying the support stability of a coalface with a large dip angle (LDA) and large mining height (LMH) under the corresponding conditions is essential to ensure safe and high-efficiency mining. This study is based on the #3(up)509 coalface of the Gaozhuang Coal Mine (GCM) affiliated with the Zaozhuang Mining Area. The authors analyzed the mechanical characteristics of support in the coalface with LDA and LMII. On this basis, the mechanical models for support tilting and sliding in the coalface were developed. Then. support stability along the coalface's strike during the normal mining period (NMP) and special mining period (SMP) was analyzed. The results show that the critical support tilting resistance during the NMP is 52.2 kN, and the critical support sliding resistance is 183.75 kN. And for the SMP, the values are 229.7 kN and 4425 kN. The use of two-leg shield support. known as ZY6600-25.5/55 (its rated working resistance is 6600 kN), is investigated. which is proved reasonable for the coalface. Finally, some technical measures, such as installing an interlock set to fasten support and adjustable lifting jack, increasing the setting load of the support, and optimizing the support displacement method, are taken to improve the coalface's overall support stability. The initial aim for safe and high-efficiency mining of the #3(up)509 coalface has been achieved through these measures.