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分散性土具有遇水易分散的特性,可导致堤坝等水利工程的冲蚀破坏。基于黏性土分散机制的研究,选用AlCl3·6H2O、MgCl2·6H2O、CaCl2及CaO作为分散性土的化学改性材料,采用针孔试验和碎块试验对其改性效果进行判别和比较。试验表明,上述改性材料均可将分散性土改性为非分散性土,显著提高土体的抗冲蚀能力。结果说明:在分散性土中掺加高价态阳离子的可溶性盐,通过置换土粒表面钠离子或降低土体碱性,减小颗粒扩散层的厚度,可抑制土体的分散性,从而达到改性的目的;根据黏性土分散机制以及改性试验结果,提出了分散性土化学改性的原则,即改性材料中含有高价态的可溶性阳离子,或改性材料呈酸性,且环境友好,价格低廉,施工方便。
Disperse soil has the characteristics of easy water dispersion, can lead to dikes and other water projects erosion damage. Based on the study of dispersion mechanism of cohesive soil, AlCl3 · 6H2O, MgCl2 · 6H2O, CaCl2 and CaO were chosen as the chemically modified materials for the dispersive soils. The modification effect was judged by pinhole test and fragment test. Experiments show that the modified materials can be modified disperse soil into non-dispersive soil, significantly improve the soil erosion resistance. The results show that adding soluble salt with high valence cations to disperse soil can restrain the dispersibility of soil by changing the sodium ion on the soil surface or reducing the alkalinity of soil and reducing the thickness of diffusion layer, According to the dispersion mechanism of cohesive soil and the results of modification test, the principle of chemical modification of disperse soil is proposed. That is, the modified material contains high-priced soluble cations or the modified material is acidic and environment- Low prices, convenient construction.