木质素衍生聚合物改良黏性土干缩开裂试验研究

Experimental Study on Cracking by Evaporation of Clay Soil Improved by Lignin-Derived Polymer

摘要

通过开展室内蒸发试验,对木质素衍生聚合物改良黏性土的保水性与抗开裂能力进行研究。分析在湿干循环过程中不同聚合物含量对改良黏性土内部水分变化的影响,并利用相关图像分析软件对土体表面的裂隙网络进行定量分析,进一步探究改良土体的裂隙发育规律。研究结果表明:(1)随着聚合物含量的增加,改良土体的水分保持能力先增强后降低,当聚合物含量为1.0%时,改良土体在常速率蒸发阶段的持续时间较素土延长约4 h,且该阶段的平均蒸发速率下降约22.95%。(2)聚合物通过团聚土颗粒和水分可有效限制土体表面裂隙的发育,但添加含量过高则易引发局部应力集中,诱使裂隙过度发育。(3)添加适量的聚合物可限制土体表面的裂隙发育,减少较宽大裂隙的产生,提升裂隙网络在湿干循环过程中的“愈合”程度。

Abstract

The water retention and anti-cracking ability of clay soils improved by lignin-derived polymer are studied by indoor evaporation tests. To explore the crack evolution patterns during the wet-dry cycle, the effects of different contents of polymer on internal moisture variation in improved soils were analyzed and the quantitative analysis was carried out for crack network on the soil surface using relevant image analysis software. The results show that: (1) The water retention capacity of improved soil is initially enhanced and then declined with increasing polymer content. When the content is 1.0%, the duration of the constant evaporation rate stage is extended by about 4 hours compared to the untreated soil and the average evaporation rate of this stage is reduced by about 22.95%. (2) The development of surface cracks is effectively limited by aggregating soil particles and water. However, excessive addition of polymer causes local stress concentration and induces extensive crack development. (3) The moderate content of polymer suppresses the development of cracks and the formation of wide cracks, thus enhances the “healing” capability of crack network during the wet-dry cycle.

关键词

有机聚合物 / 黏性土 / 湿干循环 / 保水性 / 抗开裂能力

Key words

organic polymer / clay soil / wet-dry cycle / water retention / anti-cracking ability

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基金资助

江苏省研究生实践创新计划项目(SJCX24_0202)

国家自然科学基金面上项目(42472333)