Scientific paper ID 2249 : 2022/3

The article shows the distribution of collapsible soils on the territory of the Republic of Bulgaria. The types of loess soils are given. The distribution of different types of loess soils and their division depending on their settlement on the territory of our country is shown on the map.

According to the Bulgarian standards for flat foundations, two types of earth foundations are distinguished according to the failure of the soil`s own weight [1]. The reasons for the failure of loess and other types of settling down soils is due to their structure and way of formation. Their main characteristic is the large settlement and uneven deformations. Large settlements are obtained with additional external loading and wetting afterwards. The main features of foundations in collapsible soils are reviewed. The methods for strengthening and improving the properties of collapsible soils, such as mechanical strengthening, surface and deep strengthening, are described. Improvement of the quality of these soils can be done by adding chemical and mechanical mixtures and substances. Use of cement-loess cushions for foundations in collapsible soils. Types of measures for foundation - constructive and waterproof - to reduce and prevent the settlement of buildings and facilities built on collapsible soils. In conclusion, it is pointed out that for the best results, a complex approach is needed in the implementation of the different types of measures for the improvement of collapsible soils.