In this paper, deformation modulus in an evaluation method of coefficient of subgrade reaction were evaluated. As a result, the variation of deformation modulus obtained from the pressuremeter tests can be suppressed its variation by considering the strain dependency of the ground rigidity. Furthermore, the relationships between the deformation modulus obtained from the pressuremeter test and the PS logging can be approximated proportionally, and the relationships between the deformation modulus and the SPT N-value are approximated by a power approximation formula with an intercept, which enable to unify evaluation of the deformation modulus.
