PREDICTION AND PERFORMANCE OF LATERAL LOAD-DEFLECTION BEHAVIOUR OF PILES

Abstract

The methods available to analyse a laterally loaded pile are mainly (i) the modulus of subgrade reaction approach (ii) p-y method (iii) elasto-plastic approach and (iv) elastic continuum approach. In the present investigation an attempt is made to study the ability of these methods to predict the observed lateral load-deflection behaviour of piles. For this purpose, some of the results of lateral load tests reported in the literature are compared with the results predicted using the above methods. It is found that the values of nh suggested by Terzaghi(1955) need an upward revision. The elasto-plastic method predicts the non-linear load-deflection curve more closely, provided the nature and the magnitude of plastic resistance variation suggested by the earlier investigators are modified. The elasto-plastic approach is used by Jain (1982) to analyse partially embedded piles. Field or laboratory load test data on partially embedded piles are not available. Therefore some model tests on partially embedded piles with and without vertical load are conducted. The load-deflection behaviour is estimated using J ain's elasto-plastic approach and compared with the test results. Jain (1982) reports that the affect of vertical load as identified by the analytical solutions is in contradiction with the laboratory and field evidence. One of the possible reasons hypothesized by Jain is that the loading mechanism used for the application of vertical load could cause restraint in the pile head. An attempt is made to examine this possibility.