The improvement of loess substrates with a new type of soil column with a reliability assessment

This paper presents a new method for the improvement of the weak structure of loess soils according to a design based on a reliability assessment of embankments on weak soils in relation to the structural design. Soil columns are produced directly in weak unsaturated loess without additives. These columns significantly increase the stiffness of the subsoil underlying the embankments, demonstrating the effectiveness of this technology, which represents an attractive alternative due to the low demand for materials, installation time and specialised equipment. The installation of the columns improves the reliability of the foundations and eliminates the effects of the mechanical characteristics of the subsoils arising from random environmental factors. The article consists of three parts. In the first part, the essence of the problem is presented, both in terms of geology and geoengineering, with a detailed description of the technology of demonstrating the effectiveness of this technology. The second part describes an analytical three-dimensional solution for a homogenised, reinforced soil under an embankment with an axis–symmetrical model of a multi-layer composite with a regular hexagonal grid of soil columns; the model takes into account the effect of the arch in the area of the embankment. The third part describes the structure of the reliability problem. Examples using real data are analysed and discussed.