过湿冰水堆积土路基填料改良方案比选与验证

Comparison and Verification of The Improvement Scheme of Subgrade Filling for Over-wet Ice Water Accumulation Soil

冰水堆积土具有棱角性差、级配不良、天然含水率高等特点,难以压实。基于现场踏勘与文献调研,通过方案比选,选用生石灰改良方案,并开展室内试验,研究了改良土的工程性质。结果表明:掺灰比从0增加到3%,土样液塑限含水率改变10%左右,塑性指数降低超过20,最大干密度、最佳含水率明显改善;掺灰量每提高1%,CBR值明显提高;掺灰比在3%~4%时改良效果显著;最佳掺灰量与土的天然含水率和最佳含水率差值有关,差值为20%时,最佳掺比4%对应的施工压实效果最佳,经济效益最优。

Fluvioglacial deposits soil is difficult to compact due to the characteristics of poor angular, uniform gradation and high natural water content of the soil particles. This paper presents a laboratory test research on the engineering properties of the selected quicklime stabilized fluvioglacial soil based on the field survey and literature investigation. The results show that the liquid limit and plastic limit of the soil samples change by about10 % when the quicklime mixing ratio increases from 0 to 3 % by weight, while the plasticity index decreases by more than 20. The maximum dry density and the optimum water content are significantly improved. Meanwhile,every 1 % increase in quicklime content will obviously increase CBR value until 3 %~4 % of quicklime content for the most satisfied improvement effect. The optimum amount of quicklime mixing ratio is related to the difference between the natural moisture content and the optimum moisture content of soil samples. When the difference is 20 %, the optimum mixing ratio of 4 % corresponds to the best compaction effect and the best economic benefit.