Variation of shear-wave propagation velocity (SWV) with depth was studied by analyzing more than one hundred actual SWV profi les. Linear, power, and hyperbolic variation schemes were investigated to fi nd the most representative form for naturally occurred alluvial deposits. It was found that hyperbolic (asymptotic) variation dominates the majority of cases and it can be reliably implemented in analytical or analytical-numerical procedures. Site response analyses for a one-layer heterogeneous stratum were conducted to fi nd an equivalent homogeneous alternative which simplifi es the analysis procedure but does not compromise the accuracy of the resonance and amplifi cation responses. Harmonic average, arithmetic average and mid-value equivalents are chosen from the literature for investigation. Furthermore, full and partial depth averaging schemes were evaluated and compared in order to verify the validity of current practices which rely upon averaging shallow depths, viz., the fi rst 30 m of the strata. Engineering bedrock concept was discussed and the results were compared.

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Swell-shrink movement of expansive soils due to seasonal wetting and drying can cause differential ground movements. This movement can inflict substantial structural damage above foundation level to lightly loaded infrastructure. To reduce this movement, techniques have been employed to either (i) chemically restrain the soil’s reactivity, (ii) control the moisture variation within the ground, or (iii) engage a footing system that can limit the impact of the stresses generated by such differential ground movements. Recently, a new concrete-free footing system has been developed in Australia in an attempt to sufficiently resist such ground movements. This system is comprised of an adjustable steel plate attached to the ground by multiple thin steel (hollow) battered mini-piles. The technology shows promise as a low-impact, cost-effective, excavation and concrete-free, innovative alternative to traditional footing systems. It is also quick and easy to install without the use of bulky and expensive equipment. Early field trial results have indicated that this new footing system can combat against and significantly reduce the transfer of the swell-shrink ground movements to a structure. This paper will describe this new footing system and report on an experimental field trial to date, which will include measured ground movements, moisture content and soil suction results vs. depth, as well as the performance of this new driven battered mini-pile group footing system.