区段煤柱的蠕变失稳机制及控制技术研究

Creep destabilization mechanism and control technology of section coal pillar

  • 摘要:
    目的 区段煤柱在长期采动压力的影响下,更容易发生蠕变变形,蠕变变形是引起煤柱内部裂纹裂隙扩展的主要原因。
    方法 建立无烟煤蠕变模型并推导本构方程及蠕变方程,通过有限差分嵌入FLAC3D软件,基于该模型及“约束−收敛法”完成不同应力释放系数下区段煤柱不同宽度的数值模拟分析。
    结果及结论 结果表明,随着煤柱留设宽度的增加,煤柱的弹性核区出现明显的时效特征;顶板压力表现出波峰型特征,巷帮表现出环峰型特征。巷道顶板位移下沉量与应力释放系数之间存在明显的线性关系。提出“全长锚固注浆加固−三维耦合支护”体系,通过该支护体系降低煤柱及巷道的蠕变失稳变形。

     

    Abstract: Under the influence of long-term mining pressure, creep deformation is more likely to occur in the section coal pillar, which is the main reason for the expansion of cracks and fissures in the coal pillar. In this paper, the creep model of anthracite coal is established and the constitutive equation and creep equation are deduced, and the numerical simulation analysis of different widths of section coal pillar under different stress release coefficients is carried out based on the model and the “constraint-convergence method” by embedding the finite difference into FLAC3D software. The results show that: with the increase of the width of the coal pillar, the elastic core area of the coal pillar shows obvious time-dependent characteristics; the pressure of the roof shows wave-peak characteristics, and the roadway sides show ring-peak characteristics. There is an obvious linear relationship between the displacement and sinking of the roadway roof and the stress release coefficient. The system of “full-length anchoring and grouting reinforcement and three-dimensional coupling support” is proposed to reduce the creep instability and deformation of coal pillar and roadway.

     

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