CATEGORISING GEOTECHNICAL PROPERTIES OF SURFERS PARADISE SOIL USING GEOGRAPHIC INFORMATION SYSTEM (GIS)

Abstract

Peat is a highly organic and compressible soil. Surfers Paradise (as a study area) has problematic peat layer which has different thickness at different locations between R.L. -10 to -19.6 m below the ground surface. Buildings in Surfers Paradise are using piled foundations to avoid the high compressibility and low shear strength peat layer. In this paper, geotechnical borelogs are compiled from 51 soil investigation reports in the study area. These borelogs data are then imported into ArcGIS10 as digital layers and converted into assessable formats by Geographic Information System (GIS). This technique has been utilised to produce digital zonation maps for the study area. The application of interpolation techniques allows the production of zonation maps and bring together years of geotechnical data. Standard Penetration Test (SPT) N values have been selected to determine the soil stiffness in the study area. These SPT-N values are then categorised to produce different zonation maps. The occurrence of peat layers can be located using these zonation maps. These GIS-based zonation maps will provide a better overview of subsurface geology, bed rock elevations, and geotechnical properties of the various soil types found in the study area.