基于挤压爆破技术的煤矿地表沉陷裂隙治理研究
Study on control of ground subsidence cracks in coal mine based onextrusion blasting technology
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摘要: 地下采煤引起的地表裂隙是开采沉陷破坏的直观表现,对建筑物和土地造成严重损害,同时贯通裂隙易造成工作面通风系统紊乱,严重影响矿井正常有序生产,因此提出切实可行的地表沉陷裂隙治理体系对地表开采沉陷研究和矿井高产高效生产具有实际意义。为解决大同矿区“双系”煤田煤矿地面沉陷裂隙,甚至局部与采空区连通的难题,以塔山煤矿30509工作面地面沉陷裂隙为工程背景,通过对目标区域裂隙特征分析,探讨了挤压爆破以及裂隙爆破充填原理,制定了裂隙爆破充填方案,确定了挤压爆破合理爆破参数,并进行了现场应用。结果表明:地面沉陷裂隙主要分为2类,沟谷东部为岩石裂隙,沟谷西部为土层裂隙,裂隙最大宽度超2 m,沉陷区域最大沉降深度达6 m。岩石裂隙采用挤压爆破充填方案,裂隙宽度大于100 cm时,采用双侧布置炸点挤压爆破法,宽度为30~100 cm时,采用单侧布置炸点挤压爆破法,宽度为20~30 cm时,采用裂隙内侧布置炸点挤压爆破法。土层裂隙采用松动爆破充填方案,裂隙宽度大于70 cm时,采用裂隙内双侧布置炸点爆破法,宽度小于70 cm时,采用裂隙内单侧布置炸点爆破法。采用铺设金属网和上部夯实土层回填技术,由于金属网比土层或岩层具有较大的抗拉强度,可确保裂隙沿金属网向下部向两侧运动,避免向上传递,同时金属网和上部夯实土层具有一定承载力,可确保地表完整和安全。实施挤压爆破后,结合地面沉降监测数据,地表沉陷裂隙得到有效改善,满足了矿井正常生产。Abstract: The surface fractures caused by underground coal mining are the intuitive manifestation of mining subsidence damage,causing serious damage to buildings and land. At the same time,the penetration fractures cause surface ventilation system disorder,which seriously affects the normal and orderly production of mines,so it is of practical significance to propose a feasible surface subsidence fractures management system for the study of surface mining subsidence and high-yield and high-efficiency production of mines. To solve the problem of ground subsidence fracture,even local connection with gob in coalfield,taking the ground subsidence fracture of No.30509 working face in Tashan Coal Mine as the engineering background,through the analysis of fracture characteristics in the target area,the extrusion blasting and fracture blasting filling principle are discussed,the fracture blasting filling scheme is formulated,and the reasonable blasting parameters are determined,and the field application is carried out. The results show that the ground subsidence fractures are mainly divided into two types:rock fractures in the eastern part of the valley and soil fractures in the western part of the valley,with the maximum width of the fractures exceeding 2 m and the maximum subsidence depth of 6 m in the subsidence area. When the width of fracture fracture is greater than 100 cm,the double side blasting method is adopted; when the width is 30~100 cm,the single side blasting point extrusion blasting method is adopted; when the width is 20~30 cm,the blasting point extrusion blasting method is used inside the fracture. The loose blasting filling scheme is adopted for the soil fractures. When the width of the fractures is greater than 70 cm,the blasting method of arranging blasting points on both sides of the fractures is adopted,and when the width is less than 70 cm,the blasting method of arranging blasting points on one side in the fractures is adopted. By using the technology of laying metal mesh and upper compacted soil layer backfill,due to the wire mesh has a greater tensile strength than the soil or rock layer,the fractures can be ensured to move from the bottom to both sides along the metal mesh and avoid upward transmission. At the same time,the metal mesh and the upper compacted soil layer have certain bearing capacity,which can ensure the integrity and safety of the surface. After the implementation of extrusion blasting,combined with ground settlement monitoring data,the surface subsidence fractures have been effectively improved to meet normal production of mine.