The top face of the 7130 working face is 2.5m sandy mudstone, and the old top is 3.6m fine sandstone. The cut-off roof is supported by the anchor beam and net cable. The supporting effect is good, which makes the roof difficult to collapse. During the job interview production and the initial caving,large-area suspended roofs are caused and the support is difficult to pull,which seriously affects the advancing speed of the working face. During the initial pressure of the old roof, the sudden collapse of large-area canopies and the dramatic roof activity bring great danger to the safety of on-site construction. In order to ensure normal safe production, during the initial release of the working face,the roof pre-splitting blasting technique is adopted to control the caving pace of the roof and greatly reduce the impact damage degree.%该矿7130工作面直接顶为2.5m的砂质泥岩,老顶为3.6m的细砂岩,因切眼顶板采用锚梁网索支护,支护效果较好,使顶板不易垮落,在工作面试生产及初次放顶期间,造成大面积悬顶,支架拉移困难,严重影响工作面的推进速度.加上老顶初次来压期间,大面积悬顶突然垮落,顶板活动剧烈,对现场施工安全带来较大危协.为保证正常的安全生产,在工作面初放期间,采取对顶板进行切顶预裂爆破技术,控制顶板垮落步距,大幅度降低了冲击危害程度.
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