Experimental and Numerical Assessment of the Bearing Capacity of Square and Circular Footings on Basanite Rock —Cape Verde Peninsula, Dakar

Abstract

Estimating the bearing capacity of rock masses through in situ testing is costly. This study experimentally and numerically evaluates the bearing capacity of footings on three basanite facies from Senegal. Reduced-scale model tests on rock blocks (150 × 150 × 75 mm and 100 × 100 × 50 mm) with square footings (32 mm side length) and circular footings (32 mm diameter) were performed until failure, under centered and eccentric configurations. The results show that experimentally, the allowable bearing capacity ranges from 16.27 to 37.32 MPa (type A blocks) and from 14.63 to 35.24 MPa (type B blocks). Including eccentric configurations, type A values reach up to 53.71 MPa. Circular footings exhibit higher bearing capacity than square footings. Two failure mechanisms are observed: punching-splitting (weathered basanites) and splitting (vacuolar and healthy basanites). Numerical modeling using PLAXIS 2D with the Hoek-Brown criterion validated the experimental trends, yielding a numerical-to-experimental capacity ratio between 1.05 and 3.01, with the best agreement observed for vacuolar basanite. The combined approach constitutes a reliable and economical alternative to in situ testing for foundation design in the Dakar region.