浅埋煤层回采过程中,矿山压力显现剧烈,压架事故时有发生。 针对回采过程中易突发剧烈的矿压现象,系统研究了煤层围岩力学特征及支护结构的受力状态。 首先采用颗粒元计算软件模拟分析采场围岩力链演化特征,随后分别建立了覆岩强力链拱失稳前、后力学模型,工作面支架受力模型,推导出强力链拱迹线方程,获得强力链拱在失稳前、后支架荷载的计算表达式,并在此基础上结合现场实测对工作面支架荷载进行了分析。 研究结果表明:煤层开挖前,煤岩体受力架构由力链网络组成,围岩的承载作用主要来自于强力链,广泛分布的弱力链仅对围岩起辅助承载作用; 煤层开挖后,强力链集结成束形成力链拱,力链拱是承载采场上方煤岩体重量的主要力系,工作面 支架仅承担位于强力链拱下方的煤岩体重量;且随工作面的推进,强力链拱不断调整,先后经历了“形成—扩展—稳定—破断” 的动态演化过程。 随强力链拱拱顶的不断发育,当其承担荷载超过自身强度极限后便会失稳破断,导致剧烈的矿压现象,工作面支架荷载大幅增加,强力链拱的失稳断裂是工作面产生强动载现象的本质原因。 研究成果合理解释了浅埋煤层工作面突发的剧烈矿压现象,为煤层的安全高效开采提供借鉴。 

In the process of shallow seam mining,the rock pressure in mine appears intense,and the collapse accidents of support occur from time to time,which seriously restricts the safe and efficient mining of coal resources. In view of the sudden and violent rock pressure in the process of coal seam mining,the mechanical characteristics of surrounding rock and the stress characteristics of support structure are systematically studied. Firstly,the evolution characteristics of the surrounding rock force chain in working face are simulated by the particle element calculation software. Then,the mechanical models before and after the instability of the overburden strong force chain arch,and the support force model are established respectively. The track equation of the strong force chain arch is deduced,and the formulas for calculating the support load before and after the instability of the strong chain arch are obtained. On this basis,the sup- port load of working face is studied,combined with field measurement. The results show that before the excavation of coal seam,the mechanical structure of coal and rock mass is composed of force chain network,and the bearing capacity of surrounding rock mainly comes from the strong force chain,while the widely distributed weak force chain only plays an auxiliary bearing role on surrounding rock. After the excavation of coal seam,the strong force chain forms a force chain arch,which is the main load bearing capacity of coal and rock mass above the stope. The support of working face only bears the weight of coal and rock under the strong force chain arch. With the advance of working face,the strong force chain arch is constantly adjusted,it has a dynamic evolution process of “ formation-expansion-stability-break- age”. The strong force chain arch development will lose stability and break,when its load exceeds its own strength lim- it,resulting in severe rock pressure phenomenon. The support load of the working face increases greatly. The unstable fracture of the strong force chain arch is the essential reason for the strong dynamic load in the working face. The re- search results reasonably explain the sudden severe rock pressure in shallow seam working face,which has theoretical significance and engineering application value for the safe and efficient mining of coal seam.