道路用水泥-粉煤灰流态固化土宏观力学性能与细观行为研究

Macroscopic Mechanical Properties and Mesoscopic Behaviors of Cement-Fly Ash Fluid Solidified Soil for Road Engineering

为探究水泥-粉煤灰流态固化土宏观力学性能和细观行为演化规律,利用X射线衍射(XRD)和扫描电子显微镜(SEM)测试方法,结合力学试验与颗粒流(PFC)离散元数值仿真试验,研究了不同配合比流态固化土在冻融作用下的强度特性,分析了其细观形貌和裂隙演化特征。研究结果表明:流态固化土的流动性与水泥、粉煤灰掺量呈正相关,粉煤灰的掺加有效降低了流态固化土的湿密度;粉煤灰火山灰反应生成的凝胶物质显著提升了流态固化土的后期强度和抗冻性;流态固化土试件裂隙在轴向应变约为1%时首次出现,之后裂隙数量呈线性增长,在轴向应变为4%~5%时趋于稳定,试件表面出现平行于轴向的贯通裂隙。

In order to explore the macroscopic mechanical properties and microscopic behavior evolution of cement-fly ash fluid solidified soil,X-ray diffraction(XRD)and scanning electron microscope(SEM)testing methods were used,combined with mechanical experiments and particle flow code(PFC)discrete element numerical simulation experiments,to study the strength characteristics of fluid solidified soil with different mix ratios under freeze-thaw action,and to analyz its mesoscopic morphology and crack evolution characteristics.The research results indicate that the flowability of fluid solidified soil is positively correlated with the dosage of cement and fly ash,and the addition of fly ash effectively reduces the wet density of fluid solidified soil.The gel material generated by the pozzolanic reaction of fly ash significantly improves the late strength and frost resistance of fluid stabilized soil.The cracks in the fluid solidified soil specimen first appear when the axial strain is about 1%,and then the number of cracks increases linearly.It tends to stabilize when the axial strain is within the range of 4%to 5%,and parallel through cracks appear on the surface of specimen.