钢纤维增强尾砂胶结充填体的力学性能与损伤机制  

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

作　　者：熊艳碧 刘晓辉 程海勇 吴顺川[1,3] 张京 刘伟铧 庹儒军 刘泽民 XIONG Yanbi;LIU Xiaohui;CHENG Haiyong;WU Shunchuan;ZHANG Jing;LIU Weihua;TUO Rujun;LIU Zemin(Faculty of Public Safety and Emergency Management,Kunming University of Science and Technology,Kunming 650093,China;School of Safety Engineering,North China Institute of Science and Technology,Langfang 065201,China;Faculty of Land Resources Engineering,Kunming University of Science and Technology,Kunming 650093,China)

机构地区：[1]昆明理工大学公共安全与应急管理学院,昆明650093 [2]华北科技学院安全工程学院,廊坊065201 [3]昆明理工大学国土资源工程学院,昆明650093

出　　处：《工程科学学报》2025年第2期234-248,共15页Chinese Journal of Engineering

基　　金：国家自然科学基金资助项目(52074121,52074137);云南省重点研发项目(202403AA080001);云南省面上基金资助项目(202201AT070151)。

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20 kg·m^(-3)时增强效果最好,但是当超过20 kg·m^(-3)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,添加钢纤维后,尾砂颗粒、纤维和水化产物形成了一个完整且更致密的结构,在加载过程中由于SF与尾砂–水泥基体之间的相互作用,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.To explore the influence of steel fibers(SFs)on the mechanical properties and damage/failure mechanisms of backfill,fiber-reinforced cemented tailings backfill(FR–CTB)is taken as the research subject to investigate the impact of SF content on the backfill mechanical properties.Digital image correlation(DIC)technology is employed to monitor the full-field strain of specimens and track crack development.Additionally,the microscopic strengthening mechanism of SF on backfill is studied.The results indicate that with increasing SF content and curing age,the uniaxial compressive strength,splitting tensile strength,and shear strength of FR–CTB increase to varying extents.The optimal strengthening effect occurs at an SF content of 20 kg·m^(-3),but this effect diminishes notably when SF content exceeds 20 kg·m^(-3).The presence of SFs significantly restrains crack expansion in the backfill,reduces stress concentration at crack tips,effectively prevents crack propagation,and improves overall specimen deformation.Compared with nonfiber-reinforced backfill,steel fiber-reinforced backfill exhibits characteristics of resisting microcracks without fracturing.DIC damage evolution images captured at various loading stages illustrate the initiation,propagation,and penetration of cracks in backfill specimens during different failure processes.Furthermore,from a microstructural perspective,the addition of SFs results in a more complete and denser structure where tailings particles,fibers,and hydration products such as hydrated calcium silicate(C–S–H)gel,flocculent ettringite(Aft),and large calcium hydroxide(CH)crystals interact.During loading,the strengthening effect of SFs is mainly manifested through bridging and pull-out mechanisms within the tail-cement matrix.The presence of hydration products increases the roughness of the SF surface,thereby enhancing friction between SF and the cement-tailings matrix.This improves the ability to absorb external loads and enhances the mechanical properties of FR–CTB.As the SF conte

关 键 词：尾砂胶结充填体 钢纤维 力学性能 损伤演化 微观特征 

分 类 号：TD853[矿业工程—金属矿开采]