巴西劈裂下全尾砂胶结充填体抗拉强度特征研究OACSTPCD
Study on Tensile Strength Characteristics of Cemented Backfill with Full Tailings under Brazilian Splitting
研究充填体抗拉强度对维护采场稳定具有重大参考价值.充填体的破坏过程也是能量耗散的过程,养护龄期、分层数等因素直接影响充填体的强度大小及能量耗散.以全尾砂为骨料,制备一组质量浓度为 78%,灰砂比分别为 1∶4、1∶6、1∶8,养护龄期分别为 3 d、7 d、14 d、28 d的胶结充填体进行巴西劈裂实验,分析了养护龄期与分层数对充填体强度、能量耗散及破坏规律的影响.结果表明:灰砂比一定时,不同分层的充填体的强度随养护龄期呈正相关关系;养护龄期一定时,强度与灰砂比呈正相关关系,分层会形成结构弱面,降低充填体强度.巴西劈裂过程中充填体的能量耗散随养护龄期的增长而增大,与强度变化特征一致;室内实验结果可以看出,充填体裂纹起裂点大多位于充填体中心点处,在破坏时主裂纹伴随无数微裂纹从中心点处开始萌生、扩展直至贯穿整个充填体,呈不规则形状向加载直径上扩散.不同分层充填体裂纹扩展较为连贯,部分充填体出现了分层界面局部错动的情况,断裂特征多为中心断裂与偏心断裂的复合式断裂.研究结果可为充填采矿设计、实际矿山充填提供理论支持.
The failure process of backfill body is also a process of energy dissipation.Factors such as curing age and delamination number directly affect the strength and energy dissipation of the backfill body.In this paper,using whole tailings as aggregate,a group of cemented backfill with mass concentration of 78%,lime-sand ratio of 1∶4,1∶6,1∶8 and curing age of 3D,7 d,14 d and 28 d were prepared for Brazilian splitting experiment.The effects of mass concentration,curing age and delamination number on the strength,energy dissipation and failure law of the backfill body were analyzed.The results showed that when the cement-sand ratio was constant,the strength of the backfill body was positively correlated with the curing age,and when the curing age was fixed,the strength and the cement-sand ratio were positively correlated,and the delamination will form the weak surface of the structure and reduced the strength of the backfill body.In the Brazilian splitting process,the energy dissipation of the backfill body increases with the increased of curing age,which was consistent with the strength change characteristics;the crack initiation point of the backfill body was mostly located at the central point of the backfill body and spread into an irregular shape to the loading diameter.The indoor test results showed that the crack initiation point of the backfill body was mostly located at the central point of the backfill body,and during failure,the main crack started to initiate and propagated from the center point with numerous microcracks until it ran through the whole backfill body.It spread into an irregular shape to the loading diameter.The crack propagation of different layered backfill bodies was more coherent,and the local dislocation of the delamination interface occurs in some of the backfill bodies,most of the fracture characteristics were the compound fracture of central fracture and eccentric fracture.
蔡发雄;孙伟;张盛友;姜明归;杨希;黄锦周池;景东
昆明理工大学 国土资源工程学院,云南 昆明 650093
矿山工程
巴西劈裂能量耗散抗拉强度胶结充填体损伤裂纹扩展
Brazilian splitenergy dissipationtensile strengthcemented backfill body damagecrack propagation
《矿产保护与利用》 2024 (004)
65-73 / 9
国家自然科学基金项目(52474131);国家自然科学基金项目(42467022);云南省基础研究项目(202101BE070001-038、202201AT070146)
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