Dispersive soil has caused innumerable water-induced erosion failures of earthen structures in arid regions up to now, among which disintegration, as the first response process, is commonly deemed as the primary inducement but with inadequate understanding. In this study, the disintegration characteristics of a compacted dispersive lean clay with sand were investigated by carrying out laboratory disintegration tests under a water immersion regime. Soil mass water content (ω), dry density (ρ_d) and total soluble salt content (η) were considered. Results suggest that for dispersive soil, (1) the disintegration process exhibited two distinct modes, which was divided by the ω near the optimum water content; (2) higher ρ_d delayed disintegration monotonously; (3) increasing η first weakened and then enhanced the disintegration, in which pattern the η at the inflection point increased with increasing ρ_d, showing a density dependence. Evolutions of representative soil morphology were illustrated. More importantly, the underlying influential mechanism of ω and η to disintegration were elaborated emphatically: (1) the initial clay dispersion level, soil consistency change, and conceptual “constraint force” exerted by soil matric suction jointly determine the disintegration modes; (2) increasing η makes the soil pore solution concentration higher and microstructure simpler, competition between the two leads to nonmonotonic change patterns of disintegration completion time (T_d) and defined velocity (V_d); the interactive effect of ρ_d and η manifests that η produces an additional influence on the base of microstructure created by ρ_d. Finally, the grey relation entropy analysis was introduced to evaluate the contributions of the three test variables to T_d and V_d. The obtained results and proposed perspectives are expected to be conducive to a deeper comprehension of the same or relevant behaviours of dispersive soils in the presence of water, so as to provide new insights for the targeted prevention and control of dispersive soil catastrophes.

中文翻译：

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土壤含水量、密度和盐度影响分散土壤崩解的特征及机理分析

到目前为止，分散的土壤在干旱地区造成了不计其数的水蚀土结构破坏，其中崩解作为第一响应过程，通常被认为是首要诱因，但认识不足。在这项研究中，通过在水浸制度下进行实验室崩解试验，研究了压实分散贫粘土与沙子的崩解特性。考虑了土壤质量含水量 ( ω )、干密度 ( ρ _d ) 和总可溶性盐含量 ( η )。结果表明，对于分散土，(1) 崩解过程呈现出两种截然不同的模式，在最佳含水量附近被ω分开；(2) 更高ρ _d单调延迟崩解；(3) 增加η先减弱后增强崩解，其中拐点处的η随着ρ _{d 的}增加而增加，表现出密度依赖性。说明了代表性土壤形态的演变。更重要的是，着重阐述了ω和η对崩解的潜在影响机制：（1）初始粘土分散水平、土壤稠度变化和土壤基质吸力施加的概念“约束力”共同决定崩解模式；(2) 增加η使土壤孔隙溶液浓度更高，微观结构更简单，两者之间的竞争导致解体完成时间（T _d）和定义速度（V _d）的非单调变化模式；ρ _d和η的相互作用表明η对ρ _d产生的微观结构基础产生了额外的影响。最后，引入灰色关联熵分析来评估三个测试变量对T _d和V _d的贡献. 所获得的结果和提出的观点有望有助于更深入地理解分散土壤在水存在下的相同或相关行为，从而为分散土壤灾害的针对性预防和控制提供新的见解。