二线水铁矿改良高岭土力学性质研究及机理分析

Mechanical Properties and Mechanism Analysis of Kaolin Improved by 2-Line-Ferrihydrite

为了研究二线水铁矿对高岭土力学性能的影响,对不同二线水铁矿掺量试样进行固结不排水(CU)三轴剪切试验、不固结不排水(UU)三轴剪切试验和扫描电镜试验,分析抗剪强度指标差异和影响力学性能机理。二线水铁矿改良高岭土抗剪强度指标均有所提高,在二线水铁矿掺量7%时改良效果最为显著;CU试验条件下黏聚力的增加对改良高岭土抗剪强度贡献更大,UU试验条件下黏聚力和内摩擦角均具有增强效果,两者共同决定高岭土抗剪强度;不同固结条件、不同剪切速率下二线水铁矿吸附包裹在高岭土颗粒表面,形成的团状物之间联结加固限制土颗粒移动空间,呈现抗剪强度增大的结果。

In order to study the influence of 2-line-ferrihydrite on the mechanical properties of kaolin,the consolidated undrained(CU)triaxial shear test,the unconsolidated undrained(UU)triaxial shear test and the scanning electron microscope test were carried out on the samples with different 2-line-ferrihydrit content to analyze the difference of shear strength index and the mechanism affecting the mechanical properties.The shear strength index of kaolin improved by 2-line-ferrihydrite has been improved,and effect is the most significant when the content of 2-line-ferrihydrite is 7%;The increase of cohesion under the condition of CU test has a greater effect on the shear strength of improved kaolin.Under the condition of UU test,both cohesion and internal friction angle have an enhanced effect,which together determine the shear strength of kaolin;Under different consolidation conditions and different shear rates,the 2-line-ferrihydrite adsorbed and wrapped on the surface of kaolin particles,and the formed agglomerates were connected and strengthened to limit the movement space of soil particles,increasing the shear strength.