深井嵌套式变截面巷道交岔点稳定性控制研究

Research on stability control of roadway intersections with nested variable cross-section in deep mine

  • 摘要: 深部矿井中,保持具有长服务年限的开拓巷道围岩稳定性十分重要,而井底车场中常存在两交岔点近距离连接使用的情形,在深部软岩环境下易出现大变形、支护失效等问题。以某煤矿嵌套式变截面巷道交岔点组围岩控制为工程背景,通过现场调研、地质勘查明晰了其具有3.9 m近距离嵌套式连接结构、变截面和大断面的属性及大范围穿层的特性,分析了在深部流变围岩下原支护方案失效的原因。为此进行精细化数值建模分析,得到主巷在三角岩柱侧的应力沿轴向存在“降低—叠加—恢复”的应力分区,两巷交叉角度越小,区域在轴向的距离越长,支承压力峰值及范围越大;变截面段随着截面的逐渐增大,围岩应力集中范围在横向与竖向均增大;塑性区在连接段发生多重叠加,宽度增加两倍以上,同时存在明显的穿层不连续状况,其范围在变截面巷道段及连接段急剧扩大。由此提出以中空注浆锚索为主的分段锚注强化控制方案,并经现场窥视与监测,加强支护有效保障了深井交岔点组围岩的稳定。

     

    Abstract: In deep mines, it is pretty important to maintain the stability of surrounding rock of development roadway with long service life.However, there are often some problems, such as large deformation and support failure in the deep soft rock environment, because of the close connection of the two intersection points in shaft bottom.This study draws on the surrounding rock control of intersection group of nested variable cross-section roadway in a coal mine as the engineering background.Through field investigation and geological survey, it clarifies the properties of 3.9 m close nested connection structure, variable cross-section and large cross-section, as well as the characteristics of large-scale layer crossing.It also analyzes the reasons for the failure of its original support scheme under the deep rheological surrounding rock.For this reason, the refined numerical modeling is carried out, and results indicate that the stress of the main roadway at the side of the triangular rock pillar has a stress subarea of "reduction-superposition-recovery" along the axial direction.The smaller the intersection angle of the two roadways, the longer the axial distance of the region, and the larger the peak value and range of the abutment pressure.With the increasing of cross-section, the stress concentration range of surrounding rock increases in both horizontal and vertical directions.The plastic zone is overlapped multiple times in the connecting section, and its width is increased more than twice.At the same time, there is an obvious discontinuity in the crossing layer, and the range of the variable cross-section roadway section and the connecting section are rapidly expanded.Therefore, this paper put forward a sectional reinforcement control scheme based on hollow grouting anchor cable, and through on-site observation and monitoring, the reinforcement support effectively ensures the stability of the surrounding rock of the deep well intersection group.

     

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