Digital Geotechnical Maps and Classification of Soil Engineering Properties by Using GIS

Abstract

Peat is a highly organic and extremely compressible soil. The Surfers Paradise study site area (Gold Coast, Queensland, Australia, located between 27.98° and 28.01° Southing, and between 153.41° and 153.43° Easting (based on the projection of Universal Transverse Mercator UTM zone 56) has a problematic multi thickness peat layer. The peat layer ranges from 0.1 – 7.0 m at different locations and at depths between 1.1 – 40.9 m below the ground surface. To avoid the effects of the highly compressible and low shear strength peat layer, the buildings in the study area have pile foundations. The site, which lies on the beach side, has the tallest high rise buildings and skyscrapers on the Gold Coast (e.g. the Q1 Tower, Queensland’s tallest building at the time of the study); it was also considered the tallest building in Australia. The literature review was undertaken to gain a geotechnical overview of problematic peaty soils in relation to the construction of buildings over such soils. The review was divided into three categories: (1) geology of the Gold Coast; (2) engineering properties of peat (organic layer) and its effects on the engineering design; and (3) Geographic Information System (GIS) implementation in the field of the geotechnical engineering, as well as its suitability to characterise the soil profile in the production of GIS based digital zonation maps.