Effect of Heterogeneous Field on Pore Pressure Development during Cyclic Loading of Composite Clays

Undrained behavior of composite clays in its natural or compacted state (e.g. core material of embankment dams) has a great importance for the geotechnical engineers. One of the main issues is evaluation of pore pressure generation. To study this issue a comprehensive laboratory investigation was conducted on kaolin-sand mixtures. Various effects of grains on pore pressure in the mixed samples, during cyclic strain controlled loading were evaluated. Results revealed presence of grains in cohesive matrix leads to a heterogeneous field of effective stress and deformation to be formed.This field in turn causes more pore pressure to be developed in composite clays having more grains.The results of this experimental research program has been presented and discussed in this paper.