Prediction model of loess immersion settlement based on improved K-G model

Abstract

Loess is a problematic type of soil with a worldwide distribution due to its collapsibility. The temporal discontinuity and spatial nonuniformity of its collapsibility can bring severe damage to building foundations, roads and water pipelines. In this study, the relationship between the saturation and K-G model parameters is established based on indoor compression tests and collapsible tests; the deformation characteristics of loess immersed in water are studied via a large-scale trial immersion pit test. The test site is a circular pit with a diameter of 10 m. The loess is immersed for 46 days; the variation in its accumulated settlement over time is recorded for 60 days, and its deformation process is simulated using a self-designed programme. Results show that for the stress–strain relationship of unsaturated loess, the relationship between equivalent suction and saturation can be obtained through the principle of deformation equivalence and fitted using the exponential function. The maximum vertical displacements calculated in the simulation and on-site immersion pit experiment are 0.036 m and 0.032 m, respectively. Such relatively good consistency indicates that the proposed method can reasonably predict the collapse behaviour of loess due to immersion. This research provides a reliable method for the numerical simulation of loess immersion deformation, and the parameters in the model only need to be determined by conventional experiments.