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复杂应力下软岩等效蠕变损伤模型及大变形规律研究

Equivalent creep damage modeling and large deformation of soft rock under complex stresses

  • 摘要: 软岩巷道在长期载荷作用下易发生蠕变损伤, 影响其稳定性。通过现场勘查及室内试验分析巷道软弱围岩力学及蠕变特性, 构建软岩非线性蠕变损伤模型, 并通过UDEC数值计算验证其合理性, 研究分析了软岩巷道变形的时效规律, 在现有支护的基础上提出了优化支护方案, 并应用于现场工程。研究表明: 巷道围岩蠕变试验中蠕变速率和变形量随应力增加而提升, 且稳态蠕变的过渡时间延长; 采用UDEC软件数值求解蠕变损伤模型, 通过数值计算得到软岩加速蠕变曲线与试验曲线吻合, 验证了模型的可靠性; 蠕变导致围岩变形与裂隙范围不断扩大, 暴露出现有支护系统的不足; 优化方案通过增加并加长锚杆同时引入预应力, 增强了支护系统的协同控制能力与稳定性。深入研究软岩蠕变损伤特性及其时间演化规律对于优化支护与保障工程安全具有重要意义。

     

    Abstract: Soft rock roadways are prone to subject to creep damage under long-term loading, infuencing their stability. This study investigated the mechanical and creep characteristics of the soft surrounding rock in field and laboratory. A nonlinear creep damage model was developed and validated using UDEC numerical simulations. The time-dependent deformation behavior was examined, and an optimized support scheme, involving lengthened pre-stressed anchor, was proposed and implemented to the field. The results show that creep rate and deformation increase with stress, prolonging the steady-state creep transition. The accelerated creep curve from simulations aligns with experimental results, confirming the model's reliability. The creep-induced deformation and expanding fissures reveal deficiencies in the original support system. The optimized scheme improves the cooperative control and stability of the support system.

     

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