Response of laterally loaded large-diameter bored pile groups

This paper presents results of full-scale lateral load tests of one single pile and three pile groups in Hong Kong. The test piles, which are embedded in superficial deposits and decomposed rocks, are 1.5 m in diameter and ap proximately 30 m long. The large-diameter bored pile groups consist of one two-pile group at 6 D (D = pile diameter) spacing and one two-pile and one three-pile group at 3 D spacing. This pager aims to investigate the nonline ar;response of laterally loaded large-diameter bored pile groups and to stu dy design parameters for large-diameter bored piles associated with the p-y method using a 3 D finite-element program, FLPIER. Predictions using soil parameters based on published correlations and back-analysis of the single- pile load test are compared. It is found that a simple hyperbolic represent ation of load-deflection curves provides an objective means to determine ul timate lateral load capacity, which is comparable with the calculated value s based on Broms' theory. Lateral deflections of bored pile groups predicte d using the values of the constant of horizontal subgrade reaction, suggest ed by Elson and obtained from back-analysis of the single pile load test, a re generally in good agreement with the measurements, especially at low loa ds.