Use Of Cpt Data For Prediction Of Bearing Capacity Of Bored Piles In Khartoum City

Abstract

The main objective of this study is to predict the bearing capacity of bored piles using a relatively cheap, fast and simple method of the static cone penetration tests (CPT) as an alternative to the rather expensive and time consuming pile load test method. The study also aims to evaluate the accuracy of some methods published in the relevant literature for predicting bored pile capacity. Pile load tests (PLT) and site investigation involving boreholes drilling and CPT activities were carried out at five sites selected for study in Khartoum City. The bored piles were tested using the maintained (kentledge) load test method to determine their allowable bearing capacity using three (Meyerhof’s, Chin's and De Beer's ) methods based on the interpretation of pile load test data to predict the ultimate capacity of such piles. Two other empirical methods based on the CPT data (Aoki and Bustamante) were also adopted to predict the ultimate bearing capacity of bored piles for the purpose of comparison in this study. It was concluded from the findings of this study that there is a poor correlation between the two empirical methods based on CPT on one hand (i.e.Bustamante's and Aoki's methods) and Meyerhof's method on the other hand. The study also indicated that there is a good agreement between the Bustamante’s method and the pile load test based Chin’s method. However, the Bustamante’s method gave a poor correlation with De Beer's method based on pile load test data. Similarly, there was a good agreement between CPT based Aoki's method and the pile load test based De Beer's method in predicting bearing capacity of bored piles. However Aoki's method showed a poor correlation with Chin's method based on pile loads test data