酸性饱水环境下煤岩试样的蠕变行为及尺寸效应

Creep behavior and size effect of coal rock specimens under acidic water-saturated environment

  • 摘要: 【目的】煤岩体作为多相复杂的非均质材料,其内部孔隙和裂隙对力学特性影响显著,特别是在水−岩相互作用和酸性环境下的蠕变行为中表现出明显的强度劣化特征,为研究相关内容,【方法】本研究通过对不同层理角度(0°、30°、60°、90°)及不同高宽比(1、1.5、2、2.5)的煤岩试样进行酸性饱水处理与蠕变力学试验,结合数字图像相关(DIC)技术分析其应变场演化与破坏机制。【结果】结果表明,酸性饱水时间和高宽比显著降低煤样强度,增强其变形特性;层理角度影响煤样的蠕变破坏模式,裂纹扩展路径因晶粒分布和层理特性而呈现复杂的非线性发展规律。应变场的不均匀分布揭示了煤样在蠕变加载过程中的裂纹扩展和聚结行为。【结论】研究表明,条带煤柱设计需充分考虑高宽比及酸性环境的影响,以保障煤矿开采的安全性和稳定性。

     

    Abstract: As a multiphase complex heterogeneous material, the internal pores and fissures of coal-rock significantly influence its mechanical properties, particularly exhibiting pronounced strength deterioration characteristics in creep behavior under water-rock interaction and acidic environments. In this study, coal-rock specimens with different bedding angles (0°, 30°, 60°, 90°) and high-to-width ratios (1, 1.5, 2, and 2.5) were subjected to acidic saturated treatment and creep mechanical tests, combined with digital image correlation (DIC) technology to analyze their strain field evolution and failure mechanisms. The results indicate that acidic saturation time and high-to-width ratios significantly reduce the strength of coal samples while enhancing their deformation characteristics; bedding angles affect the creep failure modes of coal samples, with crack propagation paths exhibiting complex nonlinear development patterns due to grain distribution and bedding characteristics. The uneven distribution of strain fields reveals the crack propagation and coalescence behavior of coal samples during creep loading. The research suggests that the influence of high-to-width ratios and acidic environment should be fully considered in strip coal pillar design to ensure the safety and stability of coal mining operations.

     

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