粉煤灰掺量对含黏粒粉砂土力学性能影响

为提高粉砂土地基抵抗循环荷载的能力，采用工业废料粉煤灰对粉砂土进行改良实验。选用五种不同配合比的粉煤灰改良饱和粉砂土，对其进行直剪试验、动三轴试验和扫描电子显微镜（SEM ）试验，分析了粉煤灰掺入量对饱和改良粉砂土抗剪强度的影响，并将不同粉煤灰掺入量的饱和改良粉砂土的应力应变曲线用Hardin-DrnevichD-H 双曲线模型进行拟合，讨论粉煤灰掺入量对拟合参数的影响，随后提出了仅考虑粉煤灰掺入量影响的动弹性模量经验公式和阻尼比经验公式，最后通过SEM试验照片对素土和15%粉煤灰掺入量的改良土的微观结构进行对比。结果表明：在一定限度内，增加粉煤灰的掺入量可以有效提高土体抗剪强度、初始弹性模量，降低阻尼比的增长速度。

Influence of fly ash content on mechanical properties of clay-containing silt soil

In order to strengthen the ability of resisting cyclic load of silt soil foundation, industrial waste fly ash was used to improve silt soil. Direct shear test, dynamic triaxial test and scanning electron microscope (SEM) test were carried out on the saturated silty soil modified by fly ash of five different proportions. The influence of fly ash content on the shear strength of saturated improved silty sand is analyzed. The stress-strain curves of saturated improved silt with different fly ash content were fitted by Hardin-Drnevich hyperbolic model, and discussing the influence of fly ash content on fitting parameters. Then, the empirical formulas of dynamic elastic modulus and damping ratio which only consider the influence of fly ash content are proposed. Finally, comparing the microstructure of plain soil and improved soil with 15% fly ash by scanning electron microscope test photos. The results show that increasing the amount of fly ash can effectively improve the shear strength, the initial elastic modulus of soil and reduce the growth rate of damping ratio within a certain limit.