{ "background": "Expansive soils present a significant geotechnical challenge for foundation design across many arid and semi-arid regions of Africa, leading to structural damage and economic loss. Current design practices often rely on imported methodologies that may not adequately account for local climatic and soil behavioural patterns. ", "purpose and objectives": "This working paper aims to adapt and evaluate a foundation design methodology, originally developed for Sudanese arid climates, for application on expansive soils in a representative arid region of Mozambique. The objective is to assess its technical suitability and performance for mitigating swell-shrink risks. ", "methodology": "The study employs a comparative analytical framework. Site investigation data from a case study location, including soil suction profiles and swell pressure tests, were used as inputs. The core analytical model is a modified volumetric strain prediction: \ = \ (\ \ - \ \) + \, where \ₕ and \ are soil-specific parameters derived from oedometer tests, and \ represents soil suction. Foundation performance was simulated under projected moisture change scenarios. ", "findings": "The adapted methodology indicated that deep, stiffened raft foundations, as per the Sudanese approach, could reduce differential settlement by an estimated 60-75% compared to conventional strip footings for the studied soil profile. Parameter uncertainty analysis showed that the swell pressure coefficient was the most sensitive variable, with a 95% confidence interval for predicted heave spanning ±18mm. ", "conclusion": "The Sudanese methodology provides a technically viable framework for foundation design on expansive soils in analogous African arid climates, such as found in parts of Mozambique. Its success hinges on accurate, site-specific characterisation of soil suction parameters. ", "recommendations": "Geotechnical investigations in target regions should prioritise the measurement of soil suction and swell pressure. Further validation through long-term monitoring of instrumented structures is essential. Design codes should consider incorporating climate-based suction models. ", "key words": "expansive
Muianga et al. (Thu,) studied this question.