PREDICTING BEARING STRENGTH CHARACTERISTICS FROM SOIL INDEX PROPERTIES

The bearing strength of foundation soil is a major design criteria for civil engineering structures. This study aims to estimate the bearing strength, namely California Bearing Ratio (CBR) and ultimate bearing capacity, from simple and easy measured soil index properties. Comprehensive literature concerning bearing strength characteristics and their prediction equations proposed by previous researchers were reviewed. Laboratory investigation was conducted on two different soils compacted at various placement conditions (i.e. moisture content and dry density) and tested using CBR and triaxial tests. Based on test results, linear relationships of unsoaked CBR and ultimate bearing capacity with the consistency factor which is formed by combining placement conditions and soil intrinsic parameters had been developed. To verify the validity of the developed linear relationship, data reported by some previous researchers were analyzed. The results revealed that the proposed relationships could predict unsoaked CBR and ultimate bearing capacity precisely with a coefficient of linearity (R2) more than 0.9. This result confirms that the proposed equations are reliable and useful to predict bearing strength parameters for different soils.