深部强采动大断面煤巷围岩外锚-内卸协同控制技术

Collaborative control technology of external anchor-internal unloading ofsurrounding rock in deep large-section coal roadway under strong mining influence

针对深部剧烈动压扰动影响下软碎煤体巷道围岩持续大变形破坏的控制难题,以某矿深部强采动影响区典型大断面软碎煤体巷道为研究对象,分析了深部煤巷经历强采动影响下的矿压显现规律,阐明了引起围岩大变形破坏的主要原因,得出了煤巷围岩的主要控制难点。基于此提出了深部强采动大断面煤巷围岩外锚-内卸协同控制技术,煤巷浅部围岩锚索注强化锚固技术提高了主体承载结构的围岩强度,为内部造穴卸压创造了良好的施工环境;两帮煤体深部应力高峰区采取大直径孔洞造穴卸压,阐明了在不破坏浅部锚固围岩稳定性基础上使煤巷两帮高支承压力峰值转移至造穴孔洞实体煤侧的卸压机制。内部大直径造穴孔的布置使深部煤岩体的变形向卸压孔洞群转移,为深部煤岩体持续向外运移提供让压补偿空间,浅部强化锚固能有效阻断深部煤岩体向煤巷空间运移,减少煤巷两帮围岩变形量;提出大断面煤巷围岩外锚-内卸的“固结修复、桁索强锚、内卸转移、内外协同”控制机理,并通过相似模拟及数值模拟的方法验证了煤巷围岩外锚-内卸协同控制技术的可行性。现场工程实践表明:煤巷采取外锚-内卸协同控制技术,有效抵御了大断面软碎煤体巷道在强采动影响下的两帮围岩大变形,显著改善了煤巷围岩应力状态。

Aiming at the control problems of continuous large deformation and failure of surrounding rock in soft-broken coal roadway under the influence of deep severe dynamic pressure disturbance,a large-section soft-broken coal roadway affected by deep strong mining in a coal mine is taken as the object,the ground pressure behavior laws of deep coal roadway under strong mining influence are analyzed.The main causes of large deformation and failure of surrounding rock are expounded,and the main control difficulties are obtained.Based on this,a collaborative control technology of external anchor-internal unloading of large section coal roadway under deep strong mining influence is proposed.The shallow strengthening anchorage technology of anchoring and grouting improves the strength of the main bearing structure and creates a good construction environment for internal unloading.In the deep stress peak area of two sides of the coal roadway,large-diameter holes are made for internal unloading and its mechanism of transferring the peak stress of two sides to solid coal of the hole on the basis of ensuring that the integrity of shallow anchored surrounding rock is not destroyed is expounded.The arrangement of internal large-diameter holes transfers the deformation of deep coal and rock mass to the unloading hole group,provides pressure compensation space for continuous outward migration and deformation.Reinforced anchorage can effectively block the migration of deep coal and rock mass to coal roadway space,and it can reduce the deformation of two sides of surrounding rock.The collaborative control mechanism of“consolidation and repair,strong anchor by truss-cable,internal unloading and stress transfer,internal and external coordination”of external anchor-internal unloading of surrounding rock of large-section coal roadway has been put forward.Through similar simulation and numerical simulation,the feasibility of external anchor-internal unloading cooperative control technology of the roadway is verified.The field engineering practice shows that the coal roadway adopts the cooperative control technology of external anchor-internal unloading,which can effectively resist the large deformation of two sides of surrounding rock in large-section soft-broken coal roadway under the influence of strong mining,and the stress state of surrounding rock is significantly improved.