双巷掘进留小煤柱护巷下深浅孔组合爆破卸压技术研究

Research on pressure relief technology of deep and shallow hole combined blasting under retaining small coal pillar in double roadway excavation

为防控双巷掘进留小煤柱护巷布置下邻空巷道大变形及强矿压灾害,以赵庄煤业为工程背景,提出了深浅孔组合爆破卸压技术。通过开展小煤柱护巷顶板力学结构和深浅孔聚能组合爆破机制研究,揭示了邻空巷道挠度和采空区顶板L的关联性,并确定顶板倾向断裂位置,明晰深浅孔组合双层位爆破消冲护巷的作用机制和深浅孔组合导向力学作用机理;并通过铰接块体等理论计算和现场试验确定了爆破方案参数。工程实践表明:深浅孔组合爆破卸压技术能够弱化坚硬复合顶板介质的储能蓄力属性,优化采空区边界顶板三角块结构,同等尺度下顶板积聚能量密度降低4000 J左右;1313工作面回采后采空区边界顶板及时垮塌,降低顶板对煤柱挤压作用,煤柱不同深度测点处应力集中系数分别为1.38和1.29,应力集中程度明显减小;邻空巷道扇形窥视结果表明低位岩层裂隙发育明显,高位岩层呈现逐步损伤、断裂状态,在顶板倾向上组合爆破能够缩减岩块B悬顶长度,破坏基本顶铰接结构,减弱岩块的回转下沉作用;13163巷顶底板、两帮最大移近量分别为440 mm和205 mm,爆破措施有效抑制了巷道变形,且未发生片帮冒顶等动力现象,达到了深浅孔组合爆破施工目的。

In order to prevent and control the disaster of large deformation and strong ore pressure in the heading roadway under the arrangement of retaining small coal pillars in double roadway heading,the pressure relief technology of deep and shallow hole combined blasting was put forward based on the engineering background of Zhaozhuang coal industry.Through the research on the mechanical structure of the roof of the small pillar roadway and the mechanism of deep and shallow hole combined blasting,the correlation between the deflection of the gob roadway and the roof L of the goaf is revealed,and the location of the roof dip fracture is determined,so as to clarify the mechanism of the deep and shallow hole combined double-layer blasting to eliminate scour and protect the roadway and the mechanism of the deep and shallow hole combined guiding mechanics;The parameters of blasting scheme are determined by theoretical calculation and field test of articulated block.Engineering practice shows that:The pressure relief technology of deep and shallow hole combined blasting can weaken the energy storage attribute of hard composite roof media,optimize the triangle block structure of the goaf boundary roof,and reduce the accumulated energy density of the roof by about 4000 J at the same scale;The boundary roof of the goaf in 1313 working face collapsed in time after mining to reduce the squeezing effect of the roof on the coal pillar.The stress concentration coefficients at the measuring points at different depths of the coal pillar were 1.38 and 1.29,respectively,and the stress concentration degree was significantly reduced;The fan-shaped peaking results show that the fractures in the lower strata are obviously developed,and the upper strata are gradually damaged and fractured.Combined blasting in the roof inclination can reduce the length of the hanging roof of block B,destroy the articulated structure of the old roof,and weaken the slewing and sinking effect of the block.The maximum displacement of 13163 roadway roof and floor and two sides is 440 mm and 205 mm respectively.The blasting measures effectively restrain the roadway deformation,and no dynamic phenomena such as wall caving occur,achieving the goal of deep and shallow hole combined blasting.