Testing of large diameter pile rock sockets with a retrievable test rig : Johnston, I W; Donald, I B; Bennet, A G Proc 3rd Australia-New Zealand Conference on Geomechanics, Wellington, 12–16 May 1980, V1, P105–108. Publ Wellington: New Zealand Institution of Engineers, 1980

Abstract

This paper describes the design, construction and use of a retrievable test rig for evaluating the performance characteristics of large diameter pile rock sockets. The test rig is prefabricated at ground level, lowered into a contract socket, and concreted into position. Large flat jacks react against the base of the socket to force a concrete annulus, representing a section of the pile shaft, upwards eventually to failure. The side shear resistance characteristics to failure and the base resistance characteristics well in excess of design load may be determined. After testing, by use of special design features, the rig and concrete may be rapidly removed from the socket to allow the contract pile to be completed. The results of two such tests conducted in a contract socket of a major construction project in Melbourne are reported to demonstrate the effectiveness of the technique.