冻结对黄土灰土碾压质量的影响

Influence of freezing on rolling quality of loess lime soil

通过对几组低温下不同冻结历时黄土三七灰土击实试验结果 ,与现场低温下施工碾压效果的对比分析表明 :冻结会对黄土灰土产生显著冻胀作用 ,直接影响碾压质量 ,当温度从 - 1℃降低到 - 9℃ ,土体压实干密度从 1 .58t/m3降至 1 .41 t/m3;在同一低温下冻结历时从 2 h增长到 6h,而土体压实干密度也相应降低 ;同时 ,最优含水量也相应减小 ,当土体含水量≤ 1 30 g/kg时 ,灰土碾压质量几乎不受冻结的影响 ,即黄土三七灰土冻结起始含水量为 1 30 g/kg。本研究还分析了灰土冻结的机理和发生发展过程 。

The results of comparing the results of several compaction test on loess lime soil (the ratio of lime to loess is 3∶7) after different frozen duration with the effect of site operation at low tempreture indicate that freezing can cause loess producing significant heaving,which directly influences rolling quality.When the temperature decreases from -1 ℃ to -9 ℃,soils dry density after packing decreases from 1.58 t/m 3 to 1.41 t/m 3.When the freezing time increases from 2 h to 6 h at the same low temperature,soils dry density decreases,and at the same time,brings down the best water content.When the water content is 130 g/kg,soil is not influenced by heaving.So the initial water content of this kind of loess lime soil is 130 g/kg.In this paper,the mechanism and development course of lime soil freezing are analysed,which offers the reference of theory and quantitative analysis for assessing operation quality of rolling lime,soil in winter and giving operation strategy.