固化剂改良水泥稳定黄土强度及水稳性研究

Firming Agent to Improve Strength and Water Stability of Stabilized Loess with Cement

为了研究水泥及微量固化剂对黄土路基强度及水稳性的影响,选择3个水泥掺量(6%、7%和8%)和4种固化剂(M1、M2、M3和M4),测试3个水泥掺量下黄土的7 d无侧限抗压强度,在8%的水泥掺量下分别加入0.2%和2%的4种固化剂,测试其7 d无侧限抗压强度、渗水系数K20和30 min冲刷量,并结合分别加入4种微量固化剂的黄土试件微观形貌图,分析固化剂改善水泥稳定黄土的机理。结果表明,水泥稳定能大幅提高黄土强度;4种固化剂成份体系不同,对水泥稳定黄土的主要作用机制也不同,主要包括离子交换作用、火山灰作用、化学反应生成Friede晶体改善作用和膨胀填充作用;固化剂类型对土壤有一定的适应性,不同土壤类型需要有选择的使用固化剂类型;各类固化剂改善黄土方式并不只是通过单一作用,而是主要机制不同的多种作用复合发生;对黄土的改善途径主要是通过提高土体颗粒粘聚性或生成更多、更强的水化产物提高强度或填充孔隙提高密实性。

In order to study the impact of cement and trace firming agent to loess subgrade strength and water stability, chose three cement content （6% , 7% and 8% ） , and four kinds of firming agent （M1, M2, M3 and M4）, tested 7 d unconfined compressive strength under three cement content. Added 0.2% and 2% of the four kinds of curing agents under 8% of cement content to tested 7 d unconfined compressive strength, permeability coefficient K20 and 30 min erosion volume. Further combined with morphology diagram of loess specimens that were added four kinds of firming agent to analyze the mechanism of the firming agent to improve the stability of cement loess. The results showed that a substantial increase in cement stabilized loess strength. There are different component systems of four kinds of firming agent which pay a various role in improving properties of stabilized loess with cement, including ion exchange, the role of volcanic ash, Friede crystals produced by chemical reaction that have improvement and expansion filler effects. Firming agent have a certain type of soil adaptability that different soil types need to use a suitable firming agent, all kinds of firming agent to improve the loess isnot just a single action mode, but through different actions, the main way to improve the loess by improving the cohesiveness of loess particles or generate more and stronger hydration products to improve the strength or filled porosity to increase compactness.