ABSTRACT
This paper deals with the identification of modulus of subgrade reaction nh for a sandy soil. The initial evaluation of nh is determined in the laboratory based on Terzaghi’s method. The evaluated value of nh is verified numerically by means of the finite element method. However, the results of numerical analysis in terms of the displacements did not match exactly to the experimental results. This fact was attributed to an inadequately determined value of nh. The difference between the results of numerical analysis and experimental outcomes formed the basis for identyfying the true value of nh in the framework of sensitivity theory. The difference in horizontal displacement is associated with the first variation of lateral deflection, while the difference between the initially evaluated value of nh and its true value is related to the first variation of modulus of subgrade reaction nh.
All discrete points located on the load-displacement curves determined in the laboratory are examined in the framework of sensitivity analysis. Consequently the proposed identification method of nh is capable of determining both the tangent and the secant constant of modulus of subgrade reaction nh.
