熊艳碧, 程海勇, 吴顺川, 张京, 刘伟铧, 庹儒军, 刘泽民. 钢纤维增强尾砂胶结充填体力学性能与损伤机制[J]. 工程科学学报. DOI: 10.13374/j.issn2095-9389.2024.04.08.004
引用本文: 熊艳碧, 程海勇, 吴顺川, 张京, 刘伟铧, 庹儒军, 刘泽民. 钢纤维增强尾砂胶结充填体力学性能与损伤机制[J]. 工程科学学报. DOI: 10.13374/j.issn2095-9389.2024.04.08.004
Mechanical properties and damage mechanism of steel fiber reinforced cemented tailing backfill[J]. Chinese Journal of Engineering. DOI: 10.13374/j.issn2095-9389.2024.04.08.004
Citation: Mechanical properties and damage mechanism of steel fiber reinforced cemented tailing backfill[J]. Chinese Journal of Engineering. DOI: 10.13374/j.issn2095-9389.2024.04.08.004

钢纤维增强尾砂胶结充填体力学性能与损伤机制

Mechanical properties and damage mechanism of steel fiber reinforced cemented tailing backfill

  • 摘要: 为探究钢纤维(SF)对充填体的力学性能与损伤破坏机制的影响,以纤维增强尾砂胶结充填体(FR-CTB)为研究对象,研究SF掺量对充填体力学性能的影响,采用数字图像相关(DIC)技术监测试件的全场应变,跟踪试件的裂纹发展,此外,从微观层面进一步研究了SF对充填体的增强机理。结果表明,随着SF掺量和养护龄期的增加,FR-CTB的单轴抗压强度、劈裂抗拉强度以及抗剪强度均表现出了不同程度的增长,SF掺量为20kg/m3时增强效果最好,但是当超过20kg/m3后增强效果显著降低。钢纤维的存在较大程度上约束了充填体裂隙的扩展,削弱裂隙尖端应力集中,有效阻止了裂纹的扩展,改善整个试件的变形。此外,SF的增强作用主要体现在桥接和拔出行为,水化产物的存在增加了SF表面的粗糙度,从而增加了SF与水泥-尾砂基体之间的摩擦力来吸收外部载荷的能量,提高FR-CTB的力学性能。最后利用SPSS曲线估计建立各龄期充填体强度计算模型,模型精度较高,可对掺钢纤维充填体强度进行预测。

     

    Abstract: In order to explore the influence of steel fiber (SF) on the mechanical properties and damage and failure mechanism of backfill, fiber reinforced cemented tailing backfill (FR-CTB) was taken as the research object to study the influence of SF content on the Mechanical properties of backfill. Digital image correlation (DIC) technology was used to monitor the full-field strain of specimens and track the crack development of specimens. In addition, the strengthening mechanism of SF on backfill was further studied from the microscopic level. The results show that the uniaxial compressive strength, splitting tensile strength and shear strength of FR-CTB increase in varying degrees with the increase of SF content and curing age. The enhancement effect is the best when the SF content is 20kg/m3, but the enhancement effect decreases significantly when the SF content exceeds 20kg/m3. The existence of steel fiber restrains the crack expansion of the backfill to a large extent, weakens the stress concentration at the crack tip, effectively prevents the crack expansion, and improves the deformation of the whole specimen. Furthermore, the enhancement effect of SF is mainly reflected in bridge and pull out behavior. The hydration products increase the roughness of SF surface, increasing the friction between SF and cement-tailings matrix consequently to absorb the energy of external load and improve the mechanical properties of FR-CTB. Finally, SPSS curve estimation is used to establish the strength calculation model of each age backfill, which has high accuracy and can predict the strength of FR-CTB.

     

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