Predicting Shallow Foundation Settlement in Sands from DMT

Skiles, D. L.; Townsend, F. C.; ,

Predicting Shallow Foundation Settlement in Sands from DMT

by D. L. Skiles, (A.M.ASCE), Gallet and Associates, Inc, Birmingham, United States,
F. C. Townsend, (M.ASCE), Gallet and Associates, Inc, Birmingham, United States,

Document Type: Proceeding Paper

Part of: Vertical and Horizontal Deformations of Foundations and Embankments

Abstract:

The dilatometer test is ideal for predicting the settlement of shallow foundations. It directly measures a modulus of the soil and has been correlated to predict stress history. Recently, design procedures have been proposed that make use of the dilatometer capabilities. In `Dilatometer to Compute Foundation Settlement', by John Schmertmann (1986b), two methods for calculating settlement were offered. The `ordinary' method predicted settlement based on the dilatometer constrained modulus alone. The `special' method used stress history to modify the predicted constrained modulus. The major problem with the use of either method is the lack of supporting data. Therefore, the results of sixteen load tests conducted in a controlled test pit were compared with the predictions offered by Schmertmann's methods. The comparisons and evaluation of the methods revealed attributes and limitations of each method. Both methods were accurate for the prediction of settlement in a highly overconsolidated sand. As the stresses increased beyond the preconsolidation pressure, the predictions were erratic and often unconservative. Questions concerning the validity of the dilatometer correlations for stress history in heavily compacted sands were also raised.

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