Published Online: 18 July 2013
Page Count: 17
Gupta, Ramesh Chandra
Senior Geotechnical Engineer, Structure and Bridge Division, Central Office, Virginia Dept. of Transportation, Richmond, VA
(Received 19 January 2013; accepted 27 May 2013)
Using a hyperbolic model and curve-fitting techniques, curves of the nonlinear side resistance (fs) versus the ratio of shaft displacement to shaft diameter (Δ/d), measured in top-down static load tests on instrumented drilled shafts in multilayered deposits of soil and intermediate geomaterials (IGMs), have been analyzed to determine the values of shear modulus (G) and ultimate side friction (fsu). Values of G and fsu for each layer of soil and IGM so determined from load tests matched well with those determined from correlations. An iterative procedure based on hyperbolic curves of fs versus Δ/d derived using values of G and fsu determined either from correlations or from load tests was used to compute or back-calculate top-down load-settlement curves. The load-settlement curves determined via this procedure matched well with those measured from the top-down load tests both when the tip bears above a cavity or very soft soils and when the tip is bearing in a firm and dense IGM. It was found that an accurate axial load distribution and settlement profile along the length of a shaft can be determined via this procedure.
Paper ID: GTJ20130016