Lateral load capacity of drilled shafts in jointed rock

Large vertical (axial) and lateral loads often act on the heads of drilled shafts in jointed rock. In current design practice, the p-y curve method used in design of laterally loaded drilled shafts in soil is adopted in the design of such shafts in jointed rock. The p-y curve method treats the soil as a continuum. The continuum model is not applicable to jointed rock, in which the joints form blocks. A new discontinuum model was developed in this thesis to determine the lateral load capacity of drilled shafts in a jointed rock mass with two and three joint sets. It contains two parts: a kinematic and a kinetic analysis. In the kinematic analysis, the removability theorem of a convex block is expanded to analyze the removability of a block intersecting a pile and the removability of a combination of blocks. Based on these removability theorems, a method was developed to select removable combinations of blocks using easily constructed 2-dimensional figures only. In kinetics, each selected removable combination of blocks is analyzed with the limit equilibrium approach to determine the ultimate lateral load capacity. Although the analysis is similar to slope stability analysis, it is more complicated with the addition of a lateral force exerted by the pile and the vertical pile load exerted on the wedge. The analysis also considers the weight of the wedge, the shearing resistance along the joints, and the vertical pile load exerted on the wedge. Simple analytical relations were developed to solve for the ultimate lateral load capacity.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Civil and Environmental Engineering

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

1999

Author dc:creator

• To, Albert C. (Albert Chi Fu), 1975-

Advisor dc:contributor.advisor

• Herbert H. Einstein.

• Civil and Environmental Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/40018

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/40018