瓜尔豆胶固化黄土的工程特性及抗冲蚀试验研究

An experimental study of the engineering properties and erosion resistance of guar gum-reinforced loess

为了减少暴雨冲刷条件下黄土边坡侵蚀的发生,提出采用瓜尔豆胶固化黄土对边坡坡面进行防护。基于直剪试验、渗透试验以及模拟暴雨边坡冲刷试验,研究了瓜尔豆胶固化黄土的工程特性及抗冲蚀能力,并对比素黄土与固化黄土的微观结构,探讨了瓜尔豆胶对黄土的加固机制。试验结果表明:瓜尔豆胶可有效增强黄土的抗剪强度和抗渗透性,固化黄土的黏聚力和内摩擦角呈现相同的变化趋势,即随瓜尔豆胶掺量增加而先增加后减小,随养护龄期增长而增加,饱和渗透系数随瓜尔豆胶掺量增加和养护龄期增长而减小;瓜尔豆胶掺量1.0%,养护龄期7 d的固化黄土相比于素黄土,黏聚力和内摩擦角提升了53.7%和5.6%,饱和渗透系数降低了78.3%;瓜尔豆胶固化黄土在暴雨冲刷条件下的坡面防护效果明显,相比于无防护边坡,坡面的累计冲刷量降低了64.4%,平均流速提升了55.2%;瓜尔豆胶对黄土的加固机制主要在于其水化反应产生的高黏度水凝胶能够填充孔隙和胶结黄土颗粒。本研究可为瓜尔豆胶固化黄土在边坡坡面防护工程中的应用及推广提供试验支撑。

To reduce the erosion of the loess slope under the condition of rainstorms,the loess cured by guar gum is used to protect the slope surface.The engineering properties and erosion resistance of the guar gum-reinforced loess are studied by conducting the direct shear test,penetration test,slope scour test in simulated rainstorm,and the curing mechanism of guar gum is studied by contrasting the microstructure characteristics of plain loess and reinforced loess.The results show that the guar gum can effectively enhance the shear strength and the anti-permeability of loess.The cohesion and internal friction angle of the reinforced loess show the same trend,and they increase first and then decrease with the increasing guar gum content,and increase with the increasing curing age.The saturated permeability coefficient decreases with the increasing guar gum content and curing age.Compared with plain loess,the cohesion and internal friction angle of 7 d cured loess with 1.0% guar gum content increases by 53.7% and 5.6%,and the saturated permeability coefficient decreases by 78.3%.The slope protection effect of the guar gum-reinforced loess under rainstorm scour condition is obvious.Compared with the slope without protection,the cumulative scour amount of the slope decreases by 64.4%,and the average slope flow rate increases by 55.2%.The strengthening mechanism of guar gum on loess mainly lies in the high viscosity hydrogel produced by its hydration reaction to fill the pores and cement loess particles.This study provides test support for the application and promotion of the guar gum-reinforced loess in slope protection engineering.