COMPUTER PACKAGE ON ESTIMATION OF LOAD-SETTLEMENT RELATIONSHIP OF AXIALLY LOADED PILES

Abstract

The axial capacity of piles is estimated using static analysis, dynamic analysis and load tests. The first two methods are supposed to provide only an approximate estimate of pile capacity. Moreover they do not predict the load-settlement behaviour. Load tests are expensive and the results may be valid only for the particular pile and site conditions under test. Further, the ground conditions which prevail at the time of load test may not remain the same subsequent to load test due to causes such as change in moisture content in the top layers, thixotropic hardening etc. Under these circumstances, the load-settlement behaviour of the pile observed from the load test can not be used directly to estimate the pile capacity. Settlement also governs the design of pile foundations. Hence there is a need for a procedure of estimating load-settlement behaviour of axially loaded piles. In order to achieve the above objective a computer program is developed in C++ language based on combination of Coyle and Reese method and Vijayvergiya method. Provision is made in the program to accommodate different site conditions. The program can be run on a "personal computer" which is easily accessible. The various parameters which govern the load-settlement behaviour of pile like adhesion factor a etc., are discussed in detail. Enough data are presented to take care of the above parameters and the same are used in the numerical examples solved in the present investigation. Making use of the program, results are obtained for a few numerical problems to bring out the following : 1. Comparison of the computed and the observed load-settlement data vii 2. Parametric studies of critical pile movement values Based on the results obtained, it is found that computed load-settlement curve and observed load-settlement curve are in good, agreement. From the parametric studies on critical pile movement values, it appears that the load-settlement curve is not very sensitive to the values of critical displacements adopted. viii