三向临空动压巷道切顶卸压技术与全锚索支护研究

Study on roof-cutting pressure relief technology for roadways with three-directional free surfaces and full anchor-cable support

  • 摘要: 目前对动压巷道围岩控制研究多聚焦于巷道处于单向或双向临空巷道的条件,而将切顶卸压与全锚索支护协同控制技术应用在三向临空动压巷道的研究较少。以平煤股份四矿己15−23100工作面三向临空动压巷道为工程背景,分析了三向临空动压巷道切顶卸压前后的围岩应力分布特征:三向临空动压巷道未开挖时塑性区范围已超过了原有支护方式的锚固范围,切顶能够改善围岩应力环境,降低支承应力峰值。原有巷道支护方式支护长度不足、预紧力低,不能对塑性区进行有效锚固,导致三向临空动压巷道出现顶板下沉大、侧壁破坏严重等现象。基于上述分析结果,提出了“切顶卸压+全锚索支护”协同控制技术,利用高强度锚索形成叠加梁结构,将顶板压力传递至深部稳定岩层;同时,通过切顶卸压爆破弱化顶板关键层,阻断应力传递路径。现场监测结果表明,实施“切顶卸压+全锚索支护”协同控制技术后,顶板最大下沉量降至184 mm,煤柱帮与实体煤帮最大变形量分别为149,122 mm,验证了该技术对三向临空动压巷道围岩控制的有效性。

     

    Abstract: Current studies on surrounding rock control in dynamic pressure roadways mainly focus on roadways under single- or two-directional free-surface conditions, while relatively few studies have applied the combined control technology of roof-cutting pressure relief and full anchor-cable support to dynamic pressure roadways with three-directional free surfaces. Taking the three-directional free-surface dynamic pressure roadway of the Ji15-23100 working face in Pingmei No. 4 Mine as the engineering background, the surrounding rock stress distribution characteristics before and after roof-cutting pressure relief were analyzed. The results showed that before excavation, the plastic zone of the three-directional free-surface dynamic pressure roadway had already exceeded the anchorage range of the original support system, and roof cutting could improve the surrounding rock stress environment and reduce the peak supporting stress. The original roadway support scheme suffered from insufficient support length and low pretension force, failing to effectively anchor the plastic zone, which resulted in large roof subsidence and severe sidewall damage in the three-directional free-surface dynamic pressure roadway. Based on the above analysis, a coordinated control technology of "roof-cutting pressure relief + full anchor-cable support" was proposed. High-strength anchor cables were used to form a superimposed beam structure to transfer roof loads to deep, stable rock strata, while roof-cutting blasting was employed to weaken key roof strata and interrupt stress transfer paths. Field monitoring results indicated that after implementing the proposed coordinated control technology, the maximum roof subsidence was reduced to 184 mm, and the maximum deformation of the coal pillar rib and solid coal rib reached 149 mm and 122 mm, respectively. These results verify the effectiveness of the proposed technology in controlling the surrounding rock of three-directional free-surface dynamic pressure roadways.

     

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