Study of Effect of Pre-consolidation Pressure by Simulating Plate Load Test using Hypo-elastic Model for Soil

Full scale field tests on soil with practical foundation size and load intensity can provide reliable information on settlement behaviour which is cost prohibitive, time consuming and sometimes nearly impossible. Next to prototype testing, in the present scenario, plate load test is the only way of determining settlement and allowable bearing capacity not withstanding its limitations. One such limitation of the plate load test is not accounting for the interaction between the adjacent footings in settlement analysis. In such cases numerical simulation by using suitable constitutive model may yield reliable results. However Plate load test results are used to evaluate the performance of the model and enhance the same so that it can be implemented in numerical analysis of any structure.

In this work numerical simulation of plate load test is done by developing a program in FORTRAN 77 using Hypoelastic model for soil. It is observed that the load displacement curve obtained from numerical analysis deviates considerably from plate load test results when the pre-consolidation pressure obtained through isotropic consolidation test is used. As the pre-consolidation pressure is an important parameter, numerical experiments were conducted for different fractions of pre-consolidation pressure which was obtained from laboratory test. It is interesting to note that for any given soil, a correction factor has to be adopted for the pre-consolidation pressure so that the results of the model are reasonably comparable with that of the plate load test results.