摘要
为探究干湿循环过程对全尾砂固结体力学性质的损伤作用,系统研究了干湿循环作用对全尾砂固结体单轴抗压强度的劣化规律,并结合压汞仪、扫描电镜和热重分析装置等测试仪器分析了干湿循环作用对全尾砂固结体的损伤机理。结果表明:养护3 d的全尾砂固结体在干湿循环作用下单轴抗压强度呈先上升后降低趋势,在干湿循环初期,固结体内部生成更多的水化产物,孔隙减少,整体结构更加致密;随干湿循环的继续进行,固结体逐渐破坏。养护28 d的固结体强度随干湿循环次数的增加逐渐降低,水泥含量越高,固结体强度的降幅越低;未经干湿循环的试件内部孔隙少,水化产物层状叠加;在干湿循环作用下,水化产物之间的连接逐渐破坏,孔隙率由35.75%增加至39.08%,且大孔占比大幅度上升。干湿循环作用引起的颗粒胀缩和水侵蚀导致固结体内部出现更多孔隙,部分孔隙联通形成大孔,水化产物减少,从而使固结体内部结构变得松散破碎,这是导致固结体损伤的主要原因。
In order to explore the damage effect of the dry-wet cycle process on the mechanical properties of the whole tailings consolidation,the degradation of the uniaxial compressive strength of the total tailings consolidated by the dry-wet cycle was systematically studied,combined with mercury intrusion testing and scanning electron microscopy.Test methods,such as thermogravimetric test and other test methods,were used to analyze the damage mechanism of the whole tailings consolidation by the dry-wet cycle.The results show that the uniaxial compressive strength of the whole tailings consolidated body cured for 3 d under the action of the dry-wet cycle increases first and then decreases.At the beginning of the dry-wet cycle,more hydration products are generated in the consolidated body and the pores decrease.The overall structure is more compact,and the consolidated body is gradually destroyed as the dry-wet cycle continues.The strength of the consolidated body cured for 28 d gradually decreases with the increase of the number of dry-wet cycles.The higher the cement content,the lower the decrease.The internal pores of the specimens without the dry-wet cycle are less,and the hydration products are layered.Under the action of the dry-wet cycle,the connection between the hydration products is gradually broken,the porosity increases from 35.75% to 39.08%,and the proportion of macropores increases greatly.The dry-wet cycle causes the particles to expand and shrink,which leads to more pores in the consolidation body.The erosion of water and the generation of cracks lead to the increase of pores in the consolidation body and the formation of macropores,and the reduction of hydration products makes the interior structure of the consolidation body loose and broken,which is the main reason that causes the consolidated body damaged.
作者
罗小峰
侯运炳
闫浩东
孙翔
LUO Xiao-feng;HOU Yun-bing;YAN Hao-dong;SUN Xiang(School of Energy and Mining,China University of Mining and Technology(Beijing),Beijing 100083,China)
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2021年第12期3730-3739,共10页
The Chinese Journal of Nonferrous Metals
基金
国家自然科学基金面上项目(51674263)。
关键词
全尾砂固结体
干湿循环
孔隙
水化产物
损伤
total tailings consolidation
dry-wet cycle
pores
hydration products
damage
