【摘要】 为了研究混合赤泥胶结特性产生机制,利用XRF、XRD、SEM等微观测试手段分析了混合赤泥在脱水干燥过程中化学成分、矿物组成、微观结构的变化,探讨了胶结强度随脱水龄期延长的变化规律。在此基础上,通过固结排水三轴剪切试验对5个脱水龄期混合赤泥的力学特性进行了研究,揭示了混合赤泥胶结强度的形成对其力学特性和结构性的影响。研究表明:混合赤泥的胶结强度的形成主要是因为烧结法赤泥中的水泥水硬性矿物的水化反应和活性氧化物的碳化反应形成的,并且主要集中在脱水龄期前70 d内;混合赤泥抗剪强度的增长与赤泥胶结强度的形成有直接关系,且主要体现在其黏聚力上;对具有相同初始物理指标、不同脱水龄期的混合赤泥,采用三轴试验各应变水平下不同脱水龄期干燥试样与刚出厂初始试样的主应力差之比所表示的结构性定量化参数,来研究结构性对变形强度的影响可以得到良好的规律性。更多还原

【Abstract】 To investigate the cementation mechanism of mixed red mud, the variations of the chemical composition, mineral composition and microstructure of mixed red mud are analyzed by means of XRD, XRF and SEM tests during the dehydrating process; and the variation of cementation strength during dehydrating is also discussed. Based on this, the triaxial shear tests under consolidation drained condition are carried out to determine the mechanical properties of five mixed red mud samples of different dehydration ages, and to reveal the influence of formation of cemented strength. The results show that the cementation strength mainly derives from the hydrating reactions of hydraulic materials like cement and carburizing reagents of activating oxide in mix red mud, and the significant growth of the strength appear within dehydration age of 70 days. It is also shown that the shear strength of mixed red mud have direct correlation with cementation strength, especially the cohesive strength. To investigate the impact of the structure on the deformation and strength of the mixed red mud, we introduce a structural parameter, which is defined as the ratio of principal stress difference of dry sample with different dehydration ages under triaxial compression to that of original sample. A good correlation between the structure and deformation and strength is found based on the structural parameter.更多还原