Abstract:
Every so often, there are technological events, which shift construction methods. The screw pier is one such example. While the screw pier has solved a problem, it has created a problem, being the need for soil testers to test sub-surface to deeper depths beyond those recommended by AS2870 for soil reactivity. Site investigations are usually conducted to minimum costs and usually to minimum depths so as to contain investigation costs. Seismic procedures have been used in mining for decades to detect sub-surface soil and rock profiles, but its use in urban construction has been slow, at least in Australia. The main reason is probably due to perceived extra cost and because the procedure is new to engineering practitioners. However investigation costs should be reduced because conventional testing schedules can be reduced. It is common to specify a soil test target depth, but seismic imaging can reach depths of 10-100m+, if specified, including rock, so costs should be contained within the original quote. On every site tested using seismic technology, significant extra geotechnical information is achieved concerning the sub-surface conditions, and sometimes, unavailable by other methods, such as depth to rock, filling depth, extent of filling, This paper should be seen as a basic introduction to seismic technology only.