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Wenbin Xu, Yalun Zhang, Kangqi Zhao, and Tong Sun, Mechanical properties, deformation response, energy evolution, and failure pattern of stratified cemented tailings backfill under triaxial compression, Int. J. Miner. Metall. Mater.,(2025). https://dx.doi.org/10.1007/s12613-025-3102-1
Wenbin Xu, Yalun Zhang, Kangqi Zhao, and Tong Sun, Mechanical properties, deformation response, energy evolution, and failure pattern of stratified cemented tailings backfill under triaxial compression, Int. J. Miner. Metall. Mater.,(2025). https://dx.doi.org/10.1007/s12613-025-3102-1
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三轴压缩下分层胶结充填体力学性能、变形特性、能量演化和破坏模式研究

摘要: 分层充填采矿法因能有效应对矿山开采中的环境和稳定性问题而被广泛应用。然而,该方法的中间层在三轴应力条件下强度较低,易发生破坏。传统通过增加中间层水泥含量以提高分层胶结充填体整体强度的方法,虽能提升强度,但会导致成本上升和环境问题。本研究提出在分层胶结充填体的中间弱强度胶结充填层中加入增强层,以优化其力学性能。本研究探讨了增强层位置(1/3、1/2和2/3)和厚度比(0、0.1、0.2和0.3)对分层胶结充填体的力学性能、变形特性、能量演化、微观结构和破坏模式的影响。结果表明,增强层的加入显著提高了分层胶结充填体的力学性能。在50 kPa的围压下,随着增强层厚度比从0增加到0.1、0.2和0.3,峰值偏应力从525.6 kPa上升到560.3 kPa、597.1 kPa和790.5 kPa,分别显著增加了6.6%、13.6%和50.4%。随着围压的增加,弹性阶段曲线的斜率变陡,塑性阶段也相应延长。此外,峰值偏应力和峰值点处的弹性应变能也相应增加。当增强层的厚度比从0增加到0.1、0.2和0.3时,弹性能从0.54 MJ·m-3增加到0.67 MJ·m-3、0.84 MJ·m-3和1.00 MJ·m-3,分别显著增加了24.1%、55.6%和85.2%。含增强层分层胶结充填体试样的内聚力和内摩擦角均高于胶结充填体试样。内聚力比内摩擦角更容易受到增强层位置和厚度比的影响。随着增强层的加入,分层胶结充填体试样的破坏形式从剪切破坏转变为劈裂胀形破坏和剪切胀形破坏。增强层的加入限制了裂纹的扩展。研究结果对分层胶结充填体在后续矿山回采充填中的应用和稳定性研究具有重要意义。

 

Mechanical properties, deformation response, energy evolution, and failure pattern of stratified cemented tailings backfill under triaxial compression

Abstract: The backfill should keep stable in the primary stope when mining an adjacent secondary stope in subsequent open stoping mining methods, and the large-size mined-out area is usually backfilled by multiple backfilling before the recovery of a secondary stope, resulting in a layered structure of backfill in stope. Therefore, it is significant to investigate the deformation responses and mechanical properties of stratified cemented tailings backfill (SCTB) with different layer structures to remain self-standing as an artificial pillar in the primary stope. The current work examined the effects of enhance layer position (1/3, 1/2, and 2/3) and thickness ratio (0, 0.1, 0.2, and 0.3) on the mechanical properties, deformation, energy evolution, microstructures, and failure modes of SCTB. The results demonstrate that the incorporation of an enhance layer significantly strengthens the deformation and strength of SCTB. Under a confining pressure of 50 kPa, the peak deviatoric stress rises from 525.6 kPa to 560.3 kPa, 597.1 kPa, and 790.5 kPa as the thickness ratio of enhance layer is increased from 0 to 0.1, 0.2 and 0.3, representing a significant increase of 6.6%, 13.6% and 50.4%. As the confining pressure increases, the slopes of the curves in the elastic stage become steep, and the plastic phase is extended accordingly. In addition, the peak deviatoric stresses and total/elastic strain energy at the peak point also increase. As the thickness ratio of the enhance layer increases from 0 to 0.1, 0.2, and 0.3, the elastic energy rises from 0.54 MJ·m−3 to 0.67 MJ·m−3, 0.84 MJ·m−3 and 1.00 MJ·m−3, representing a significant increase of 24.1%, 55.6% and 85.2%. The internal friction angle and cohesion of the SCTB specimens are higher than those of the CTB specimens, however, the cohesion is more susceptible to enhance layer position and thickness ratio than the internal friction angle. The failure style of the SCTB specimen changes from shear failure to splitting bulging failure and shear bulging failure with the presence of an enhance layer. The crack propagation path is significantly blocked by the enhance layer. The findings are of great significance to the application and stability of the SCTB in subsequent stoping backfilling mines.

 

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