Model tests on jacking installation and lateral loading performance of a new skirted foundation in sand

Abstract

A new type of caisson, composed of two skirted side semicircles and a skirted middle rectangle, was used as a breakwater foundation in Xuyu Port, China. In this study, large-scale laboratory model tests were carried out on jacking installations and lateral loading of this new skirted foundation in sand. Test results showed that the soil pressure acting on the caisson's inner skirt was larger than the outer soil pressure during jacking installation; whilst the tip resistance was greater than skirt friction. Penetration resistance was well predicted with the jacked pile theory and cone resistance. Overturning failure of the foundation occurred under the lateral loading. Ultimate lateral loads displayed a descending trend with increasing loading position height, whereas the corresponding moments exhibited an increasing trend. Parameters were suggested to calibrate the expression of circular foundation for purpose of estimating the combined capacity of the new skirted foundation. Passive soil pressure zones occurred on the outer surface of the new skirted foundation in the loading direction. In contrast, active soil pressure zones were found in the area with opposite loading direction. The net incremental soil pressure was positive in the loading direction, suggesting that the rotation center was beneath the model base.