Horizontal Subgrade Modulus of Granular Soils

Although the horizontal subgrade modulus plays a significant role in problems dealing with lateral-load carrying capacity of piles, a rather wide range of values is available in literature depending upon the equation, chart, or table used to obtain the modulus. This task is further complicated on account of lack of uniformity of definitions used. The accuracy of simple, let alone elaborate, methods of analysis for lateral-pile capacity is often controlled by the accuracy of the modulus value used in the computations. For many engineering computations, the engineer must strike a balance between a simple and an accurate enough procedure to obtain the modulus. One of the simplest ways of computing the modulus is by means of empirical and semiempirical relationships. In this paper, the available empirical and semiempirical relations for estimating the horizontal subgrade modulus of granular soils are reviewed, and then a simple relationship for computing the horizontal subgrade modulus of such soils is presented. The values of the modulus from the proposed relationship are compared with those given by others.