双聚合物改良分散性土的力学特性及机制研究

Study on mechanical properties and mechanism of dual polymer modified dispersive soil

为了解决分散性土在引水灌溉等工程建设中产生的安全性问题,本文以吉林西部地区分散性盐渍土作为研究对象,研究了木质素和黄原胶2种高分子聚合物协同处理对分散性土的分散性以及力学特性的改良效果,分析了冻融循环作用对改良土的分散性与力学特性的影响规律,并从微观角度揭示改良机制。结果显示,改良后土体的分散性明显降低,强度明显提高。其中木质素的质量分数3%与黄原胶的质量分数3%协同处理并养护28 d后,改良土的无侧限抗压强度达到171.12 kPa,较原状土强度提升约2.5倍;在试验设计的改良剂配比中,该配比对分散性土综合性能提升最显著,抵抗冻融劣化的效果亦最佳。微观结构分析显示,木质素纤维在改良土体内部起到了立体格栅般的桥接作用,黄原胶独特的黏结能力也使得土颗粒间连结愈加紧密。

In order to solve the safety problem of dispersive soil in the construction of water diversion and irrigation other projects,this paper takes the dispersive saline soil in the west of Jilin Province as the research object,studies the improvement effects of synergistic treament with lignin and xanthan gum high molecular polymers on the dispersivity and mechanical properties of dispersive soil,and analyzes the influence of freeze thaw cycle on the dispersivity and mechanical properties of improved soil,and explain the improvement mechanism from a microscopic perspective.The results showed that the dispersity of the improved soil was significantly reduced,and the strength was significantly improved.Among them,3%lignin and 3%Xanthan gum were treated and cured together for 28 days,and the unconfined compressive strength of the improved soil reached 171.12 kPa,about 2.5 times higher than the strength of the undisturbed soil.In the improved ratio of the design of experiments,this ratio has the most significant improvement in the comprehensive performance of the dispersive soil,and the effect of resisting freeze-thaw degradation is also the best.Micro-structure analysis shows that lignin fiber plays a three-dimensional grid like bridging role in the improved soil,and the unique bonding ability of Xanthan gum also makes the soil particles more closely connected.The synergistic treatment of lignin and Xanthan gum has obvious advantages in dispersive soil,which provides a theoretical basis for the improvement of dispersive soil in practical engineering construction.