Influence of possible water saturation of loess soil on the stress-strain state of the foundations of a multi-storey building

Abstract

The consequence of human activity in the field of construction is an increase in the density of buildings. As a result, areas that were previously considered risky from the point of view of the quality of soil conditions or increased saturation of the soil stratum with underground communications are allocated for development. All these factors are of direct importance when it comes to the use of loess soils as a basis for the design, erection and operation of new construction facilities.
 Loess soils cover about 80% of the territory of Ukraine. These soils have a negative feature - the ability to reduce their mechanical properties when in contact with water and give additional collapse deformations. Therefore, a significant part of the buildings is erected in such soil conditions. That's why, the foundation structures of these buildings and structures must be designed taking into account the possibility of uneven deformations. For this reason, the relevance of taking into account the joint work of the "collapsible base - foundation - above-ground structures" system does not decrease, but even increases.
 Loess soils in a dry state have good physical and mechanical characteristics due to structural bonds. However, with increasing humidity, the soil porosity undergoes a sharp change, the compressive strength decreases rapidly, structural bonds are destroyed and collapse deformations occur. 
 The search for a reliable and economical option for foundation structures is an urgent issue in the design of buildings and structures at the modern level. This is especially relevant in the conditions of construction on soils capable of collapsing with possible water saturation.
 The work presents a variant design of the foundations of the building. At the same time, the impact of possible water saturation of the loess soils of the base on the stress-strain state of the foundations was considered. Different schemes of possible soaking of loess soils were considered. Different sizes and locations of water saturation zones within the building plan were considered. An analysis of the results of the numerical simulation of the joint work of the elements of the "base - foundation - above-ground structures" system was performed. The choice of the most reliable foundation option is substantiated. It has been confirmed that the size and location of loess soil water saturation zones influence the redistribution of stresses in foundation structures. It is shown that the use of variable design of foundations allows choosing an economical and reliable foundation option, if we consider different options for their parameters and take into account the negative factors of the soil conditions of the construction site and emergency situations that may occur during the operation of the building.