摘要
邱集煤矿1102工作面顶板为致密坚硬的复合灰岩顶板,基于四周固支岩梁模型,理论计算未切顶前顶板初次垮落和周期垮落步距,发现工作面推采后出现采空区大跨度悬顶等问题。为解决这一难题,分析计算合理悬顶长度,提出工作面深孔爆破闭合切顶技术;拟采用聚能爆破定向断裂顶板形成闭合贯穿裂缝,帮助采空区顶板随推采及时垮落,减小采空区悬顶长度;根据工程地质条件,针对性设计聚能预裂爆破切顶高度、切顶角度和炮孔间距,并推导出合理封堵长度计算公式,形成了一套完整的爆破切顶参数选取方案。经现场试验证明,爆破切顶后,相邻炮孔间裂缝贯通形成闭合切缝面,采空区悬顶沿闭合切缝面及时垮落,复合顶板初次垮落步距从45m降低为24m,周期垮落步距从19m降低为11m,分别降低了46.6%和42.1%,垮落效果良好,可为类似地质条件下解决大跨度悬顶问题提供参考。
The roof of 1102 working face in Qiuji Coal Mine is a dense and hard composite limestone roof.Based on the model of surrounding fixed rock beam,the first caving and periodic caving steps of the roof before roof cutting are calculated theoretically.It is found that the large-span suspending roof appears in the goaf after the working face advancement.In order to solve this problem,the reasonable length of the suspending roof is analyzed and calculated,and it’s puts forward to use deep-hole blasting to close and cut the roof.The concentrated energy blasting is applied to form the closed through cracks on the directional fractured roof,to help the roof of the Goaf collapse in time with the mining advancement and reduce the length of the suspending roof in the goaf.According to the geological conditions of the project,the height and angle of roof cutting,and the spacing of the blastholes are specifically designed,forming a complete set of design scheme of blasting cutting parameters.The field test shows that after blasting,the cracks between adjacent blastholes cut through to form a closed seam surface,and the suspending roof of the goaf collapses along the closed seam surface in time.The first caving step of the composite roof shortens by 46.6%from 45 m to 24 m,and the periodic caving step shortens by 42.1%from 19 m to 11 m.The caving effect is favorable,which provides a reference for solving the problem of large-span suspending roof under the same geological conditions.
作者
武善元
时启鹏
李廷春
云明
赵仁乐
WU Shan-yuan;SHI Qi-peng;LI Ting-chun;YUN Ming;ZHAO Ren-le(Shandong Energy Linyi Mining Group Co.,Linyi 276017,China;Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation,Shandong University of Science and Technology,Qingdao 266590,China)
出处
《煤炭工程》
北大核心
2021年第7期65-70,共6页
Coal Engineering
基金
国家自然科学基金(41772299,51604166,51279096)。
关键词
复合灰岩顶板
垮落步距
悬顶长度
闭合切顶
爆破参数
composite limestone roof
collapse step
roof suspending length
closed roof cutting
blasting parameter
