无煤柱开采围岩控制技术及应用

Strata control technology and applications of non-pillar coal mining

我国煤矿无煤柱开采技术研究与应用已有60多年。综合分析了沿空留巷、沿空掘巷、跨巷开采及采空区布置巷道等无煤柱开采方法及适用条件、围岩控制取得的研究成果。在沿空留巷方面的主要内容为:不同开采系统的沿空留巷类型、围岩变形与破坏特征;沿空留巷结构力学模型及围岩与支护作用关系;沿空留巷巷内基本支护、巷内加强支护、巷旁支护形式及支护性能;爆破与水力压裂围岩卸压机理及技术;沿空留巷断面优化及维护时间控制;沿空留巷支护设计原则及沿空留巷安全技术。在沿空掘巷方面,论述沿空掘巷的类型及小煤柱尺寸设计方法,分析沿空掘巷围岩结构特征、围岩变形的主要影响因素及沿空掘巷围岩控制技术。介绍跨巷无煤柱开采的类型,分析巷道与采煤工作面底板的垂直距离、工作面边界至巷道的水平距离等参数对跨采巷道围岩变形的影响。论述在采空区布置巷道的方式:在采空区形成巷道和掘进巷道,分析采空区巷道的应力环境及施工存在的难点。介绍陕西何家塔煤矿支卸组合泵充混凝土支柱沿空留巷、山西野川煤矿泵充钢筋混凝土墙与水平长钻孔水力压裂卸压沿空留巷围岩控制2个应用实例,分析沿空留巷围岩变形控制效果。最后,提出无煤柱开采方法及围岩控制技术的改进意见与发展方向。

Non-pillar coal mining has been developed and applied for more than 60 a in China coal mines.The research achievements on non-pillar coal mining methods,applicable conditions and strata control technology,such as entry retained along gob side,entry driven along gob side,cross mining over roadway,and entry arranged in gob area,are comprehensively analyzed.The main contents about entry retained along gob side are:various types associated with different coal mining systems,rock deformation and damage features,rock structure mechanical model and interaction between surrounding rock and support;the types and mechanical performances of basic support,enhanced support in entry and the support set along entry side;the rock destressing mechanism and techniques on blasting and hydraulic fracturing;the optimization of entry cross section and maintaining period;support design principles and safety technology for entry driven along gob side.In regard to entry driven along gob side,the patterns and design methods for slender coal pillar are discussed,the rock structure features,main affecting factors of rock deformation and surrounding rock control techniques are analyzed.The forms of non-pillar cross mining over roadway are introduced,and the effects of vertical distance from cross working face floor to roadway roof and horizontal distance from face edge to roadway on its deformation are explained.The entry layout patterns in gob area,including entry maintained and driven in gob are introduced,the stress fields and construction difficult points associated with these entries are discussed.Two study cases are introduced:the entry retained along gob side maintained by the combination of pumped concrete prop and hydraulic fracturing destressing in Hejiata coal mine in Shaanxi Province,another one controlled by pumped rebar concrete wall and hydraulic fracturing destressing with long horizontal boreholes in Yechuan coal mine in Shanxi Province,and the strata control effects of the entries retained along gob side are analyzed.Finally,the improvement suggestions and development direction for non-pillar coal mining methods and strata control technology are put forward.