Lateral Load Capacity of Drilled Shafts in Jointed Rock
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 129, Issue 8
Abstract
Large vertical (axial) and lateral loads often act on the heads of drilled shafts in jointed rock. In current design practice, the curve method used in design of laterally loaded drilled shafts in soil is often also used for shafts in jointed rock. The curve method treats the soil as a continuum, which is not appropriate in jointed rock, particularly when failure occurs due to sliding on joints. A new discontinuum model was developed to determine the lateral load capacity of drilled shafts or piers in a jointed rock mass with two and three joint sets. It consists two parts: a kinematic and a kinetic analysis. In the kinematic analysis, Goodman and Shi’s block theory is expanded to analyze the removability of a combination of blocks laterally loaded by a pier. Based on the expanded theory, a method was developed to select removable combinations of blocks using easily constructed two-dimensional diagrams. In the kinetic analysis, each kinematically selected removable combination of blocks is examined with the limit equilibrium approach to determine the ultimate lateral load capacity. Although the procedure is similar to slope stability analysis, it is more complicated with the addition of a lateral force and the vertical load exerted by the pier. Simple analytical relations were developed to solve for the ultimate lateral load capacity.
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Copyright © 2003 American Society of Civil Engineers.
History
Received: Aug 17, 2000
Accepted: Nov 25, 2002
Published online: Jul 15, 2003
Published in print: Aug 2003
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