多场耦合环境下尾砂胶结充填体力学特性研究进展

    Research progress on the mechanical properties of cemented tailings backfill under multi-field coupling environments

    • 摘要: 在采场充填体强度设计中,充填材料配比通常是基于室内标准养护条件下的充填体强度作为确定依据,但是室内标准条件养护下的充填体与深部矿山多场耦合的原位环境下形成的充填体力学特性差异显著,影响充填强度需求设计的合理性,进而使得矿山充填成本过高。本文旨在系统梳理多场耦合环境下尾砂胶结充填体的力学响应机制与微观结构演化规律。采用文献综述与理论分析相结合的方法,系统梳理了国内外关于应力场、温度场及其与渗流场、化学场耦合作用对尾砂胶结充填体力学特性影响的最新研究成果;重点分析了研究装置从一维低压到三维高压、从常温恒温到深部地热变温环境的演变历程,并对比分析了不同多场耦合路径下充填体的宏微观测试数据。研究结果表明:在应力场方面,施加应力场通过物理压密作用和加速胶凝材料水化反应的方式显著提升了充填体单轴抗压强度;在温度场方面,高温虽然提供热活化能加速了充填体早期强度的形成,但长期处于高温环境会导致水化产物分布不均及微观孔隙结构劣化,导致充填体强度降低。在多场耦合方面,发现排水条件下施加应力能有效抑制高温带来的微观结构劣化,即高应力能补偿高温所造成的热损伤,其中养护应力主要影响充填体的干密度与孔隙率,而温度主要影响胶凝材料水化反应速率。在实验室孪生模拟深部采场充填体所处的多场耦合养护环境是开展相关研究的基础,未来研究应从静态单一场分析转向动态多场耦合分析,聚焦于研发能够模拟三维应力场及实时动态调控的多场耦合养护试验装置,基于装置进行深入探究,以实现充填配比设计的精准化与经济化。

       

      Abstract: In the strength design of stope backfills, the mixture ratio of backfill materials is conventionally determined based on the strength of backfill specimens under laboratory standard curing conditions. However, a significant discrepancy exists between laboratory standard curing conditions and the actual underground environment characterized by multi-physics field coupling. This discrepancy compromises the rationality of strength design, leading to either excessive backfill costs. This paper aims to systematically review the mechanical response mechanisms and microstructural evolution laws of Cemented Tailings Backfill (CTB) under multi-field coupling environments. Combining literature review with theoretical analysis, this study systematically summarizes the latest domestic and international research findings concerning the effects of stress fields, temperature fields, and their coupling with seepage and chemical fields on the mechanical properties of CTB. Emphasis is placed on analyzing the evolution of experimental apparatus from uniaxial low-pressure to three-dimensional high-pressure systems, and from constant ambient temperature to deep geothermal variable-temperature environments. Furthermore, macro-microscopic experimental data under different multi-field coupling paths are comparatively analyzed. The results indicate that regarding the stress field, the application of stress significantly enhances strength through physical compaction and the acceleration of the hydration reaction of cementitious materials. Regarding the temperature field, although high temperatures provide thermal activation energy to accelerate early strength formation, long-term exposure to high geothermal environments leads to uneven distribution of hydration products and coarsening of microscopic pores. In terms of multi-field coupling, it is found that applying stress under drainage conditions effectively inhibits microstructural deterioration caused by high temperatures. Curing stress dominates the dry density and porosity of the backfill, while temperature governs the degree of hydration; notably, high stress can compensate for the thermal damage caused by high temperatures. Reproducing the deep in-situ multi-field coupled environment in the laboratory serves as the foundation for related research. Future studies should shift from static single-factor analysis to dynamic multi-field coupling, focusing on the development of experimental systems capable of simulating three-dimensional geostress states and real-time dynamic control, thereby achieving precision and economy in deep mine backfill design.

       

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