CALIBRATION OF METHODS FOR DESIGNING LARGE-DIAMETER BORED PILES: SERVICEABILITY LIMIT STATE

抄録

Limit-state design methodologies for serviceability of foundations are an important area under development. Due to various sources of uncertainty, settlement analysis models and the soil or rock properties required for settlement analysis may be in error; hence any settlement estimate is a random variable. To develop limit-state design codes for large-diameter bored piles, analysis methods for estimating the settlement of large-diameter bored piles need to be carefully calibrated. This paper aims at calibrating four analysis methods for bored piles in soils (Vesic's elastic method, Mayne and Harris's analytical solution, O'Neill and Reese's load-transfer method, and a method based on load-transfer curves established in this paper based on Hong Kong data) and three methods for bored piles socketed in rocks (Vesic's method, Kulhawy and Carter's method, and a load-transfer method using the correlations established in this paper based on Hong Kong data). For rock-socketed piles, two methods for estimating the rock deformation modulus are further studied: One based on a correlation with rock quality designation and the other based on a correlation with rock mass rating. These analysis models have been calibrated at the working load level using 36 cases of static loading tests on large-diameter bored piles in Hong Kong with complete soil and rock information. The effects of construction on pile settlement have also been included.