基于半平面体理论的煤柱底板应力传递规律
Coal Pillar Floor Stress Distribution Laws Based on Half-plane Body Theory
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摘要: 为了对煤柱底板应力传递规律进行深入研究，根据弹塑性力学中半平面体理论，建立了煤柱底板传递力学模型，结合应力叠加原理得到煤柱底板应力分布计算公式，并利用 MathCAD 得到了煤柱底板的垂直应力和水平应力云图。以大同矿区侏罗系煤层为例，分析了不同类型煤柱底板的垂直应力和水平应力的分布特征。分析得到：煤柱的垂直应力的应力量值和影响范围最大，在应力传递的过程中起到了主导作用；边界煤柱底板的垂直应力集中区影响深度范围最大，大区段煤柱(20 m)次之，小区段煤柱(10 m)最小。对煤柱的不同布置方式的底板垂直应力进行了分析，煤柱重叠布置使得底板应力集中区的深度和范围增加。以大同侏罗系煤层群开采为实例，重叠煤柱综合作用下，3-5#煤垂直应力为12.4～17.3 MPa，较无煤柱条件下提高了1.3～6.2 MPa。在125～280 m对应的区域垂直应力升高明显，建议3-5#煤层工作面回采巷道布置尽量避开该区域。Abstract: Coal pillar floor stress transfer law was researched by half plane body theory of elastic-plastic mechanics, and coal pillar floor stress transfer mechanics model is established. Combined with stress superposition principle, we get the calculation formula of coal pillar floor stress distribution, and coal pillar floor horizontal stress and vertical stress cloud was got by using MathCAD. Datong Mining Area Jurassic coal was selected as an example, different types of coal pillar horizontal stress and vertical stress distribution characteristics were analyzed. The stress magnitude and scope of vertical stress of coal pillar is the biggest, which played a leading role in the process of stress transfer. The depth of vertical stress concentration area of boundary pillar is the biggest, the depth of large section coal pillar (20 m) was the second, and the depth of small section coal pillar (10 m) was the last. Different arrangement of floor vertical stress of coal pillar was analyzed, and the overlap arrangement of coal pillar makes the depth and scope of floor stress higher. The mining of Jurassic coal group in Datong Mining Area was selected as an example, comprehensive overlapping action of coal pillar makes stress of 3-5# coal seam from 12.4 MPa to 17.3 MPa, vertical stress are increased from 1.3 MPa to 6.2 MPa under the condition of no pillar. In the area of 125 m to 280 m, the vertical stress increased obviously, we suggest that the arrangement of mining roadway at 3-5# coal seam working face should avoid this area.
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Keywords:
- half-plane body theory /
- coal pillar /
- floor stress /
- stress transfer /
- elastic-plastic mechanics /
- roadway layout
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