Pile group settlement analysis on the basis of Static Load Test

Abstract

Settlement of large pile groups is most often estimated by the Alternative Foundation Method. However, this method has some limitations related to assumed uniformity of pile loads. A very big problem is also related to estimating the stiffness of subgrade loaded by a group of piles. Similar problems arise when piled foundation is numerically modelled in Finite Element Method or Boundary Element Method programmes. The results obtained are highly dependent on the input data, especially on characteristics describing soil subgrade stiffness and strength and moduli at pile – soil contact. The paper presents an example of using the results of trial static calculations for the pile made using a technology not identical with that ultimately implemented for the project. The subgrade stiffness modulus was determined with Inverse Analysis using bored pile test load. The results attained were used for further calculations (forecast) the settlement of prefabricated driven pile (a single one) and then to estimate of pile group settlement under full load from bridge structure abutment.