【摘要】 为了使低液限黄河冲积粉土达到铁路路堤填料要求,采用木质素和石灰对其进行改良。通过一系列土工试验对比不同改良剂的改良效果和影响规律,获得合理的改良剂和掺入比;利用扫描电子显微镜(scanning electron microscope, SEM)观测土样微观结构的变化,揭示干湿循环对其微观结构的影响。结果表明:石灰掺量在3%～4%、木质素与石灰的配合比控制在2∶1～3∶1时,木质素-石灰改良粉土可达到铁路路堤填料的强度要求,且木质素与石灰的掺入比为2∶1时改良效果最好;木质素和石灰的掺入,使得黄河冲积粉土的黏聚力和内摩擦角增加、水稳性提高、微观结构更为稳定;当木质素和石灰掺入比为6%∶3%时,木质素-石灰改良粉土具有更好的抵抗干湿循环的能力。更多还原

【Abstract】 In order to make the low liquid limit Yellow River alluvial silt meet the requirements of railway embankment fillers, lignin and lime were used to improve it. The improvement effect and the rule of influence of the improver were studied and a reasonable improver and mixing amount were obtained by a series of soil experiments. The change of the microstructure of soil samples was observed, and the effect of dry-wet cycle on microstructure was revealed by the scanning electron microscope(SEM). The results show that when the lime content is 3%～4% and the mix ratio of lignin to lime is controlled within the range of 2∶1 to 3∶1, the lignin-lime improved silt can meet the engineering requirements of the railway embankment filler. The maximum improvement effect can be achieved when the mixing ratio of lignin to lime is 2∶1. With the addition of lignin and lime, the cohesion, internal friction angle, water stability and microstructure of the Yellow River alluvial silt increase. When the ratio of lignin to lime is 6%∶3%, the resistance to dry-wet cycle of the lignin-lime improved silt is better.更多还原