Seminar - Ezzat William - Bringelly Shale - Testing It Even Higher

Wednesday, October 8, 2003, 1.10 - 1.50 pm
Civil Engineering Lecture Room 3

Abstract

Bringelly shale is a major formation of the Wianamatta group that outcrops over a large area of Western Sydney. The shale is comprised predominantly of claystones and siltstones with occasional sandstone layers. It is highly compacted, weakly cemented, and contains significant amounts of swelling minerals. Because of difficulties in obtaining samples from conventional drilling methods tests have been performed on reconstituted samples compressed to the same density as the in-situ shale. The results of triaxial tests on the highly compressed specimens are compared with the behaviour of reconstituted specimens at lower density. It is found that the high stress results in changes in the soil response and reduction in the frictional strength. To interpret the effects of structure and bonding in the shale requires an understanding of the reconstituted de-structured material. To determine appropriate de-structured behaviour the specimens must be subjected to high stresses to reproduce the low porosity.