3种生物聚合物改良粉土的持水特性研究

针对黄河流域水土流失防治，以往多采用水泥等灰色材料进行加固筑堤，但生态环境破坏严重。为响应黄河流域生态保护和高质量发展的国家战略，采用环境友好的生物聚合物对黄河流域典型粉土进行改良，通过WP4C仪测量生物聚合物改良粉土的持水特性，并从微观角度分析了生物聚合物改良粉土持水特性的机制。研究结果表明，与未改良土相比，生物聚合物改良粉土饱和含水率增大，孔隙比增大，持水能力显著提高。黄原胶、结冷胶、瓜尔胶改良粉土的持水能力均随着掺量的增加而增加，结冷胶改良的效果优于黄原胶、瓜尔胶。其机制为生物聚合物颗粒经过水合作用形成水凝胶，填充颗粒间孔隙，增加颗粒之间的黏结性。而且黄原胶、结冷胶改良粉土中形成类似蜂巢结构的孔隙空间，为其提供储水空间，进而提高改良土的持水特性。上述研究结果可为生物聚合物安全、科学地应用于黄河流域水土流失的防治提供科学依据。

Water retention characteristics of silt improved by three types of biopolymer

In the past, grey materials such as cement were used to build and reinforce embankments in the Yellow River basin to prevent soil erosion, which caused serious damage to ecological environment. In response to the national strategy of ecological protection and high-quality development of the Yellow River basin, environment-friendly biopolymers were used to improve the typical silt in the Yellow River basin. In this paper, the water retention characteristics of biopolymer-improved silt are measured with WP4C instrument, and the mechanism of biopolymers to improve the water retention characteristics of silt is analyzed from a microscopic point of view. Compared with unimproved soil, the water content of biopolymer modified silt after saturation increases, the void ratio increases, and the water holding capacity is significantly improved. The water retention capacities of the silts modified by xanthan gum, gellan gum and guar gum increase with increasing the gum content, and the improved effect of gellan gum surpasses those of xanthan gum and guar gum. The improvement mechanism can be explained that the biomolymer particles form hydrogel through hydration, filling the pores between particles and increasing the adhesion between particles. In addition, pore space similar to honeycomb structure is formed in the improved silt by xanthan gum and gellan gum to provide water storage space, thus improving the water retention characteristics of the improved soil. The above research results can provide a scientific basis for the safe and scientific application of biopolymer in the prevention and control of soil erosion in the Yellow River basin.