Study of relationship between cone index and deformation modulus of various soil types

The article presents mathematical models used to predict deformation modulus of cohesive soil (loamy, sandy loamy, clayey soil, forest soil and wetland soil) based on the resistance to indentation of a standard conic indenter (cone index). The studied material includes reference data and experimental results obtained by independent researchers, as well as the theoretical formulae of contact mechanics. The research methods are a computational experiment and methods of estimated data approximation. Calculations were performed using Maple 2015 and MS Excel 2013 programs. Logarithmic dependencies of deformation modulus of clay, loamy and sandy loam soil from the conic index were obtained, varying from 0.1 to 5 MPa. The developed dependencies correspond to the results obtained by previous researchers for cohesive soils, divided into categories by the strength (less than 0.7 MPa, 0.7-2 MPa and more than 2 MPa). Moreover, linear dependences of deformation modulus of forest soil and wetland soil on the cone index were obtained, varying within the limits up to 1.5-2 MPa. The results of calculations for the proposed formulae correspond to experimental and reference data obtained by previous researchers for organomineral soils