AN INVESTIGATION OF TWO PEAT SLOPE FAILURES IN THE WICKLOW MOUNTAINS

Abstract

Although peat slope failures have occurred in Ireland for many thousands of years, their causal factors and the triggering mechanisms involved are poorly understood. A particular barrier to quantitative assessment of the risk of failures is the lack of knowledge of the geotechnical proper ties of peat and its role in failures. In order to advance the understanding of these issues case history data is invaluable. This paper describes a case study from the Wicklow mountains where a desk and remote sensing based study was used to identify peat slope failures. Subsequently, detailed field studies were carried out at two failure locations. It was found that although the full causal factors at the time of failure are unknown, a common factor was that the failure took place in a zone of highly decomposed and relatively low-fibre-content peat. A revision of the standard test method for fibre content for use in peat soils is proposed. N. Boylan (corresponding author; email: boylan@civil.uwa. edu.au), Centre for Offshore Foundation Systems, University of Western Australia; M. Long, School of Architecture, Landscape and Civil Engineering, University College Dublin.