Abstract The present study focuses on the compositional analysis and phase relationship of soil mass and their role to trigger landslides in the Babai River watershed, Siwalik zone of Nepal. A total of 76 landslides are selected for sampling and further analysis among 769 active landslides from the total study area. For the classification of soil, the Unified Soil Classification System (USCS) is adopted by using both the sieve and hydrometer analysis. The centered log-ratio (clr) and mean component fraction of sand, silt, and clay are obtained from the compositional analysis by using R and CoDapac v.2.02.21 software. Correlation of phase relationships like moisture content, unit weight, specific gravity, void ratio, porosity, and degree of saturation of each soil samples are obtained. The results indicate that the degree of saturation is highly correlated with moisture content and void ratio but less correlated with the specific gravity and dry density. Furthermore, the highly correlated variables are checked by multiple regression analysis and the best-fitted regression equation was obtained from the phase relation. The centered log-ratio and mean log of silt/clay fraction indicate that silt and clay constituents in the soil are responsible for the landslide initiation in the study area.

中文翻译：

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尼泊尔锡瓦利克区巴拜河流域活动滑坡土体成分分析及相关系

摘要 本研究的重点是土壤质量的组成分析和相关系及其在尼泊尔锡瓦利克区巴拜河流域引发滑坡的作用。在整个研究区的769个活动滑坡中，共选择了76个滑坡进行采样和进一步分析。土壤分类采用统一土壤分类系统（USCS），结合筛分和比重计分析。使用 R 和 CoDapac v.2.02.21 软件从成分分析中获得砂、粉砂和粘土的中心对数比 (clr) 和平均组分分数。获得了每个土壤样品的含水量、单位重量、比重、空隙率、孔隙率和饱和度等相关系的相关性。结果表明，饱和度与含水率和空隙率高度相关，而与比重和干密度的相关性较小。此外，高度相关的变量通过多元回归分析进行检查，并从相位关系中获得最佳拟合回归方程。淤泥/粘土比例的中心对数比和平均对数表明土壤中的淤泥和粘土成分是研究区滑坡开始的原因。