淤泥质土的固化机理研究

Study on mechanism of muddy soil stabilization

为了消除腐植酸对水泥固化处理淤泥质土的不利影响,阐述了淤泥质土中腐植酸的特性,探讨了腐植酸对水泥水化过程的影响机理,提出了从减薄黏土双电层厚度、添加膨胀组分、提高固化土早期强度、提高土壤pH值、裂解有机质大分子结构以及调节水泥离子和黏土颗粒的活性的角度固化淤泥质土的对策.抗压强度试验表明,三乙醇胺和氢氧化钠双掺效果优于单掺效果,不仅可以加速早期强度的增长,而且对后期强度发展有利;随着生石灰、高效减水剂、水玻璃和生石膏掺量的增加水泥固化土的强度均呈现先提高后降低的规律.正交试验得到了复合固化剂中各添加剂间的最优配比.强度对比试验表明,复合固化剂的固化强度优于单掺水泥和水泥复掺固化剂SN201的固化效果,充分验证了其在强度提高方面的优越性.

In order to get rid of the adverse effects of humic acids on the treatment of muddy soil with cement, the property of humic acids in muddy soil was expounded, and the influence mechanism of humic acids on the cement hydration process was discussed. The countermeasures to treat the muddy soil were put forward, including that reducing the thickness of electric double layer of clay, adding expansion component to soil, accelerating the early strength development, increasing the pH value of admixture, destroying the structure of organic matter macromolecule, adjusting the activities of cement and clay particles. The compression tests indicate that the stabilization effect with admixture of sodium hydroxide and triethanolmine was better than that with either component individually used, and the admixture of them not only increases the early strength, but also has advantage in lately strength development for cement stabilized soil. The compressive strength of stabilized soil increases initially and deceases after peak value with increasing the amounts of lime, high efficiency water reducing agent, sodium silicate and calcium sulfate respectively. The optimum mixture ratio of these additives is preliminarily determined through orthogonal experiments. Strength comparison tests indicate that the soil stabilized With the admixture as advised above is superiority in the strength compared with the cement singly used and the cement mixed with SN201 stabilizer.