Modification of non-linear model of Fahey for coarsegrained soils of Tehran, using pressuremeter tests

The stiffness of soils is not constant and it is highly strain dependent. Some nonlinear models such as Fahey's model for sands have been proposed for sands but these models can not be the representative of the behavior of most coarse-grained soils such as alluvial sediments of Tehran. In this paper, firstly some data of deformation modulus of several coarse-grained soils such as Tehran's soil are presented as a function of strain. Then the weakness of nonlinear models such as Fahey's model in predicting the behavior of these kind of geo-materials is presented. In next step, a new proposed model, which is in fact a type of corrected Fahey model, is explained and then a comparison is done for Tehran soil. The foundation of Milad tower is modeled using FLAC software incorporating new model and then calculated settlement is compared with measured one using micro-geodetic method.