煤矿巷道常布置于薄层状煤岩互层中,围岩表现出非对称和不均匀性的破坏特征,采用常规的开放式对称支护技术方案效果较差,不利于此类巷道的长期维护。结合淮北矿区孙疃煤矿频繁穿越煤岩层区的巷道工程,总结了包括肩角失稳破坏、一帮内挤、底板(梁)凸起及全断面失稳等多种不均匀破坏特征,并分析其主要影响因素;提出以锚杆、锚索、注浆等主动支护为主体枸建整体封闭式支护,辅以结构补强的技术原理,通过锚杆与锚索预应力的协同作用、锚固体与围岩注浆的相互强化作用、锁腿与U型钢拱形支架的结构补强作用等形成协同支护效应,以有效控制穿煤岩层区层状围岩巷道的不均匀破坏。采用顶帮锚架注、拱脚连续锁腿约束及底板钻锚注等方法合理实施巷道全断面加固,并在孙疃煤矿埋深570m穿煤岩层区域巷道应用,巷道稳定后围岩收敛变形控制在180-220mm范围,保障了施工安全和长期稳定。
Roadways are usually constructed in thin bedded coal-rock crossovers and subjected to asymmetric and inhomogeneous damages. Application of conventional unsealing symmetric supporting shows poor performance and worse long-term maintenance effect. Taking the frequent cross- over-through roadway construction of Suntuan coal mine as an engineering example, we summarize its typical asymmetric and inhomogeneous damage features, such as shoulder angle fracture, large sidewall deformation, floor heave and whole section instability etc, and analyze its main influential factors. Whole section sealing support was mainly constructed by active support such as anchor, bolt and grout- ing, assisted by other structure supplement. Inhomogeneous damage of roadways in thin bedded coal-rock crossovers could be controlled by combination of prestress synergy function of anchor and bolt, interaction strengthen of surrounding rocks and grouting, structure supplement of leg-lockedequipment and U type shed. Whole section strengthening was implemented through bolt-shed-grouting on roof and sidewall, continuous restraint on arch and bolt-grouting on floor. The technology has been successfully applied in a 570 m deep roadway in coal-rock crossovers, whose deformation was con- trolled between 180 mm and 220 mm, guaranteeing of construction safety and long-term stability.