水下抗分散水泥土正交试验及配比优化方法研究∗

Research on Orthogonal Experiments and Optimization of Mixing Ratios for Underwater Anti‑Dispersion Cement‑Stabilized Soil

摘要:

水流经过桩基时会形成漩涡侵蚀床面，影响桩基及上部结构的稳定性，冲刷治理是工程界关注的热点问题。 为促进固化土技术在桩基冲刷修复中的应用，设计开展了抗分散水泥固化土系列正交试验。针对高岭土和淤泥土，选用 PAM、EVA、黄原胶、HPMC 四种抗分散剂，采用平均效果分析和极差分析，研究了抗分散剂种类、抗分散剂掺量、含水量和水泥掺量对流动度、浊度、7 d 和 28 d 无侧限抗压强度的影响。结果表明：对于高岭土，抗分散剂掺量从 0.25‰ 增大到 1‰，水泥土流动度减小 20%，浊度减小 25%，抗分散剂掺量对流动性和抗分散性的影响显著。对于淤泥土，对抗分散性影响显著的仍是抗分散剂掺量，而对流动性的影响显著的则是含水量，含水量从 1.4 倍液限增大到 2.0 倍液限，水泥土流动度增大 45%。基于综合平衡法、矩阵分析法和多元线性回归模型，提出了一种抗分散水泥土配比设计方法，研究得到了高岭土和淤泥土抗分散水泥固化土的推荐配比，其在泥沙起动实验中的抗冲刷特性明显优于原始土样。

Abstract:

Water flow around pile foundations can create vortices that erode the bed surface, compromising the stability of both pile foundations and superstructure. Therefore, addressing scour management has always been a hot topic in engineering. To advance the application of cement-stabilized soil technology in scour repair for pile foundations, orthogonal experiments were designed and carried out on dispersion-resistant cement-stabilized soils. Four types of anti-dispersants, PAM, EVA, xanthan gum, and HPMC, were selected for kaolinite and silt soils. The effects of anti-dispersants type, antidispersant dosage, water content, and cement dosage on fluidity, turbidity, and unconfined compressive strength at 7 and 28 days were studied using average effect and range analysis. The results showed that for kaolinite, increasing the anti-dispersants content from 0.25 ‰ to 1 ‰ decreased the fluidity of the cement-stabilized soil by 20% and turbidity by 25%, demonstrating a significant impact on both fluidity and anti-dispersion properties. For silt soils, the anti-dispersant dosage significantly influenced anti-dispersion properties, while water content was the main factor affecting fluidity. When the water content increased from 1.4 w_L to 2.0 w_L, the fluidity of cement-stabilized soil increased by 45%. Based on the comprehensive balance method, matrix analysis method, and multiple regression linear model, a method for designing the mixing proportions of anti-dispersion cement-stabilized soil was proposed. The recommended ratio of kaolinite and silt soils showed significantly better anti-scour characteristics in the sediment initiation experiments compared to the original soil sample.