Numerical modeling of influence of soil mass reinforcement with cement-sand grouting on foundation deformation

Abstract

In the last few years of buildings the objects are developed increasing the number of storeys on foundation not designed for this purpose. It's absolutely impossible to use such construction sites without specific engineering survey. In this case, the most perspective is the soil reinforcement method as the latter decreases the material consumption and underpinning expenses and increases the distribution of base load-bearing capacity. The aim of the research is to study the stress-strain state of subsoil and estimate the reinforcement impact on the load-bearing capacity and foundation deformation. The methods used in the study: the analysis of materials of engineering-geological researches for designing object. Strength and deformation characteristics of soils were determined by the laboratory and field methods. The jet grouting was applied in reinforcement of building foundations. This technique depends on the characteristic features of the foundation soil, relevant type of foundation and surrounding conditions. The numerical analyses were carried out with three typical load intensities, proving that the intensity of the foundation settlement being influenced by the growth of soil stiffness and strength. The results. Simulation determines the stress-strain changes of soil mass under constructed building and predicting changes under conditions of underpinning by bored piles. Vertical soil displacements is 7,9 mm before underpinning, while it is 6,5 mm after underpinning. It is defined that the use of jet structures to strengthen the ground base allows increasing the rigidity of the base and reducing its vertical movement by 20 %.The hypothetical displacements of the base to the optimal values were identified at varying its mechanical properties.

Keywords

• soil
• stress-strain state
• reinforcement
• high-pressure injection
• finite element method
• modulus of deformation