复合顶板中厚煤层切顶卸压留巷无煤柱开采技术

Non-pillar mining technology of medium thick seam with roof cutting and pressure released retained gateway and complex roof

为实现切顶卸压留巷无煤柱开采,合理设计了恒阻大变形锚索支护参数,以城郊煤矿中厚煤层21304工作面复合顶板为工程背景,采用FLAC3D数值模拟分析了预裂爆破切顶高度、切缝角度对留巷围岩应力、位移的影响,通过现场试验确定了切缝施工单孔定向爆破半径及装药结构,并分别对恒阻锚索受力、顶板离层、支柱压力与活柱下缩量、巷道侧向应力等进行了跟踪监测研究。研究结果表明:切顶卸压留巷无煤柱开采需准确确定巷道围岩变形的关键部位,以及恒阻大变形锚索支护工艺,合理切顶高度为8 m、合理切缝角度为15°;试验中采用单孔切缝定向爆破半径及装药结构,实施效果良好;经对恒阻锚索受力、顶板离层、支柱压力与活柱下缩量、巷道侧向应力等进行了跟踪监测,巷道留巷整体效果好。

In order to realize a non pillar mining with a roof cutting and pressure released retained gateway,the support parameters of the constant resistance and high deformation anchor was rationally designed. With the medium thick seam of No. 21304 coal mining face with the complex roof in Chengjiao Mine as the engineering background,a FLAC3Dnumerical simulation was applied to analyze the pre-fractured roof cutting height and cutting angle affected to the stress and displacement of the surrounding rock along the retained gateway. the directional blasting radius and charging structure of the single borehole drilled with the slotting were determined by the site test. A tracing and monitoring study was conducted on the constant resistance anchor stressed,roof bedding,support pressure and cylinder yielding,gateway lateral stress and others individually. The study results showed that the non pillar mining with the roof cutting and pressure released retained gateway in Chengjiao Mine determined the key location of the surrounding rock deformation along the gateway and designed the support technique of the constant resistance and high deformation anchor. The rational roof cutting height was 8 m and the rational cutting angle was 15°. In the site test,the direction blasting radius and changing structure of the slotting single borehole were applied and the implemented effect was excellent. The tracing monitoring was conducted on the constant resistance anchor stressed,roof bedding,support pressure and cylinder yielding,gateway lateral stress and others and the whole effect of the retained gateway was good.