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条带开采广泛应用于深部煤层,合理的条带煤柱尺寸对提高煤炭采出率和保护地表地貌都具有十分重要的意义。通过总结平面应变状态下Wilson准则、Mohr-Coulomb(M-C)准则、广义Matsuoka-Nakai(M-N)准则、广义Lade-Duncan(L-D)准则和外接圆Drucker-Prager(D-P)准则等5种强度准则的统一表达式,进而建立条带煤柱的极限强度、屈服宽度和留设宽度的统一计算公式,探究条带煤柱设计的强度准则效应,并得出煤层黏聚力和内摩擦角的影响特性。研究结果表明:建立的统一计算式涵盖文献已有解,且应用非常方便;条带煤柱设计的强度准则效应显著,Wilson准则和M-C准则的结果过于保守,外接圆D-P准则应用需谨慎,应优先选用广义M-N准则或广义L-D准则;煤层黏聚力和内摩擦角对条带煤柱设计的影响明显,应充分考虑煤层的强度参数变化。该研究结果可为条带煤柱的合理设计与施工提供一定的理论指导。
Strip mining is widely used in deep coal seams, reasonable strip size of coal pillars to improve coal recovery rate and the protection of surface topography are of great significance. By summarizing five kinds of strength criteria of Wilson criterion, Mohr-Coulomb (MC) criterion, generalized Matsuoka-Nakai (MN) criterion, generalized Lade-Duncan (LD) criterion and circumcircle Drucker-Prager Unified expression is established, then the unified formula of ultimate strength, yielding width and leaving width of strip coal pillar is established, the strength criterion effect of strip coal pillar design is explored, and the influence of cohesion and internal friction angle of coal seam is obtained . The results show that the established unified calculation formula covers the literature, and the application is very convenient. The strength criterion of strip coal pillar design has significant effect. The results of Wilson criterion and MC criterion are too conservative. The application of circumcircle DP criterion should be cautious. The generalized MN criterion or generalized LD criterion is preferred. The influence of cohesion and internal friction angle of coal seam on the design of strip coal pillar is obvious. The change of strength parameters of coal seam should be fully considered. The results of this study can provide some theoretical guidance for the rational design and construction of strip coal pillar.