Effects of temperature and age on physico-mechanical properties of cemented gravel sand backfills
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Effects of temperature and age on physico-mechanical properties of cemented gravel sand backfills JIANG Fei-fei(江飞飞)1, 2, ZHOU Hui(周辉)1, 2, SHENG Jia(盛佳)3, 4, KOU Yong-yuan(寇永渊)5, LI Xiang-dong(李向东)3 1. State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, China; 2. University of Chinese Academy of Sciences, Beijing 100049, China; 3. National Engineering Research Center for Metal Mining, Changsha Institute of Mining Research Co., Ltd., Changsha 410012, China; 4. School of Resource & Environment and Safety Engineering, Hunan University of Science and Technology, Xiangtan 411201, China; 5. Jinchuan Group Co., Ltd., Jinchang 737104, China © Central South University Press and Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract: Cemented backfill used in deep mines would inevitably be exposed to the ambient temperature of 20−60 C in the next few decades. In this paper, two types of cemented gravel sand backfills, cemented rod-mill sand backfill (CRB) and cemented gobi sand backfill (CGB), were prepared and cured at various temperatures (20, 40, 60 C) and ages (3, 7, 28 d), and the effects of temperature and age on the physico-mechanical properties of CRB and CGB were investigated based on laboratory tests. Results show that: 1) the effects of temperature and age on the physico-mechanical properties of backfills mainly depend on the amount of hydration products and the refinement of cementation structures. The temperature has a more significant effect on thermal expansibility and ultrasonic performance at early ages. 2) The facilitating effect of temperature and age on the compressive strength of CGB is higher than that on CRB. With the increase of temperature, the compressive failure modes changed from X-conjugate shear failure to tensile failure, and the integrity of specimens was significantly improved. 3) Similarly, the shear performance of CGB is generally better than that of CRB. The temperature has a weaker effect on shear strength than age, but the shear deformation and shear plane morphology are closely related to temperature. Key words: cemented backfill; gravel sand; temperature; physico-mechanical properties; deformation characteristics Cite this article as: JIANG Fei-fei, ZHOU Hui, SHENG Jia, KOU Yong-yuan, LI Xiang-dong. Effects of temperature and age on physico-mechanical properties of cemented gravel sand backfills [J]. Journal of Central South University, 2020, 27(10): 2999−3012. DOI: https://doi.org/10.1007/s11771-020-4524-6.
1 Introduction Over the past decades, the backfill mining method has been widely used in underground mines
due to its advantages in dealing with mined-out voids, managing ground pressure, improving mining environment and increasing ore-recovery ratio [1−4]. One of the critical issues in deep backfill mining is the increasing ambient
Foundation item: Project(P2018G045) supported by the Science & Technology Research and Development Program of China Railway; Project(2018CFA
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