本研究探讨了不同干湿循环条件下玻璃纤维和石灰复合改良云南红土的效果及作用机理。通过无侧限抗压强度试验、直接剪切试验、X射线衍射及扫描电镜分析,确定了最佳纤维和石灰掺量,并分析了干湿循环次数和脱湿温度对红土及复合土强度和矿物组成的影响。结果显示:复合改良显著提高了红土强度;干湿循环次数增加导致红土抗剪强度下降,而复合土抗剪强度则呈现先升高后降低的趋势;红土的抗剪强度在不同温度下表现出显著差异,复合土抗剪强度则随着脱湿温度升高而增加;随着脱湿温度升高,红土中石英含量先降后升,复合土中碳酸钙含量增加;扫描电镜分析结果显示,玻璃纤维和石灰通过增强胶结力、抑制裂隙发展,改善了土体微观结构,弱化干湿循环的侵蚀作用,从而提升红土强度和抗干湿循环能力。

This study explores the effect and mechanism of glass fiber and lime in improving Yunnan lateritic soil under different wetting-drying cycle conditions. Through unconfined compressive strength tests, direct shear tests, X-ray diffraction (XRD), and scanning electron microscopy (SEM), the optimal fiber and lime contents were determined, and the effects of the number of wetting-drying cycles and drying temperature on the strength and mineral composition of the lateritic soil and composite soil was analyzed. The results show that the composite improvement significantly enhanced the strength of the lateritic soil. As the number of wetting-drying cycles increased, the shear strength of the lateritic soil decreased while the shear strength of the composite soil first increased and then decreased. The shear strength of the lateritic soil varied significantly across different temperatures while the shear strength of the composite soil increased with drying temperature. With rising drying temperatures, the quartz content in the lateritic soil first decreased and then increased while the calcium carbonate content in the composite soil increased. The SEM analysis reveals that the composite improvement by glass fiber and lime enhanced bonding strength, inhibited crack development, improved the microstructure of the soil, and mitigated the erosive effect of wetting-drying cycles, thereby improving the strength and resistance of the lateritic soil to wetting-drying cycles.