An Investigation on the Reliability of Pile Toe Defect Rectification Method used in Sri Lanka

Abstract

The foundation is the vital part of any infrastructure as it will be the element that will eventually bear the superstructure load. In cases where the soil conditions are poor and structural loads are high, pile foundations are used more often. These piles should be defect free to not fail under the structural loads. So, the identification and rectification of such defects should be performed at early stages of construction. In this study, the reliability of the rectification method used for pile toe defect rectification in Sri Lanka (pile coring and grouting method) is studied. Raw data from 11 piles, found as defective through Cross-hole Sonic Logging (CSL) test, are analyzed. Six of these piles were retested after rectification using the same test while the remaining piles were retested using High Strain Dynamic (PDA) test. Out of the six piles, three showed an increase in the effective area, two still showed some defective areas and one was an incomplete test due to a blocked tube. Out of the five tested through PDA test, only one showed an acceptable β value, which is a parameter that represents the scale of the pile defects identified. Therefore, it was concluded that even though there is an overall improvement in the pile effective area, some defects could still exist within the pile that may require to be rectified and retested for integrity. It was also concluded that due to the comparatively lower accuracy of the PDA test, acceptance of a defective pile based only on this test without rectification is not acceptable. Future research suggestions were made to further refine the results of this research and to expand the scope to defects in other regions of the pile.