An Improved Experimental Test Set-up to Study the Performance of Granular Columns
Black, J
Research Student, School of Civil Engineering, Queen’s University Belfast, Belfast, United Kingdom

Sivakumar, V
Senior Lecturer, School of Civil Engineering, Queen’s University Belfast, Belfast, United Kingdom

Madhav, MR
Professor Emeritus, Geoenvironmental Engineering Centre, J. N. Technical University, Hyderabad, India

McCabe, B
Lecturer, Department of Civil Engineering, National University of Ireland, Galway

(Received 17 June 2005; accepted 24 January 2006)

Abstract

This paper describes an innovative design of a newly developed large test setup for testing the performance of footings supported on soft clay reinforced with granular columns. This advanced testing method is used to examine the settlement of footings supported on granular columns. Two important features of the equipment are (a) the axial loading system which allows samples to be consolidated under K_o condition while the load is applied onto a small foundation area of the sample, and (b) a relatively large sample size of 300-mm diameter and 400-mm high. The system is also equipped with pressure cells located beneath the footing and top cap to measure the pressure distribution with respect to foundation displacement and a lateral strain gage to monitor boundary effects. This paper reports on some of the early findings from the preliminary tests carried out using this equipment. Samples for testing were prepared by consolidating kaolin slurry in a large one-dimensional consolidation chamber. The granular columns were installed using the replacement method by compacting crushed basalt (uniformly graded with 90 % between 1.5–2-mm particle sizes) into a preformed hole. The preliminary tests have yielded promising results, validating the functionality of the equipment and support the prospect of increasing the knowledge with respect to settlement response and design of a footing supported on granular columns.

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Author Black J, Sivakumar V, Madhav MR, McCabe B Title An Improved Experimental Test Set-up to Study the Performance of Granular Columns Symposium , Committee on