Field and numerical investigation of soil–atmosphere interaction at Nairobi, Kenya

Abstract

This paper investigated the soil–atmosphere interaction for foundation on black cotton soil by numerical analysis using data from Nairobi, Kenya. A three-dimensional numerical model was developed to study the behaviour of black cotton soil under atmospheric influence, using ABAQUS computer program. Swelling-induced strains, caused due to the changes in moisture contents, were used to numerically simulate the shrink/swell behaviour of black cotton soils. The evapotranspiration, calculated by empirical equation, was used as the boundary condition to predict the distribution of the water content and the vertical movement within the foundation. The results showed that the migration of moisture and the vertical movement within the foundation were obviously affected by rainfall and evapotranspiration, especially at a depth of 0–1.5 m. The water content changed a little below the depth of 3 m. There was significant settlement due to soil drying in the dry season. However, the settlement seemed to have recovered during the rainy season that followed. The maximum settlement and the maximum heave reached 50 and 34 mm, respectively. A field test was conducted, which verified that the predicted values had a reasonably good agreement with the measured values.

Keywords:

• soil–atmosphere interaction
• field test
• numerical analysis
• moisture migration
• foundation deformation

Acknowledgement

The authors thank the engineering technicians of China Road and Bridge Corporation (Kenya) for the data collected by them and the anonymous reviewers for their careful review and critics, which helped in improving the article.

Funding

This work was funded by National Natural Science Foundation of China [grant number 51378121].