DEVELOPMENT OF MATLAB ALGORITHM FOR THE CASAGRANDE MODEL FOR ANALYSIS OF PRE-CONSOLIDATION AND PRE-COMPRESSION STRESS IN SOILS

Abstract

Pre-consolidation/Pre-compression stress is a soil mechanical stability criterion, which is often used to
determine the maximum external loads an undisturbed soil and structures can withstand without
irreversible deformation. The most acceptable and widely use method of estimating pre-consolidation
stress in the soil is the method developed by casagrande in 1936. In this method, determining preconsolidation
stress require accurate location of the point of maximum curvature on the soil compression
curve which involves a lot of subjective perception or interpretation. In order to prevent such subjective
interpretation in the determination of the point of maximum curvature, Mathematical model for
determining the pre-consolidation stress was developed. The algorithm was implemented in MATLAB,
thereby creating room to proper visualization of the graphical interface. The model was validated with
data from Nigeria and Brazil. The results were compared with those generated with the previous EXCEL
representation of the model by Dias Junior. The result showed a strong correlation with coefficient of
determination r² = 1. The study contributes to a non-subjective way of estimating soil pre-consolidation/
pre-compression stress from uni-axial experiment data, thereby assisting in prevention of
soil compaction and consequent degradation.