No! Site Investigation (SI) which includes field testing, instrumentation and boreholes where soils are extracted is not sufficient to tell you the complete story of a construction site. There is a need for a geophysics study for a construction site which is extremely sensitive to geotechnical and geological changes.

In one of my latest work in integrity study involving three dams in Sabah requires geophysics. What information which are not conveniently available in SI and instrumentation? First of all, water table and/flow net are not available in SI except for possible correlation and extension. None of these are deterministic by nature and hence, electrical resistivity tomography (ERT) will indicate the actual profile which usually are heuristic in nature. Soil packing and floaters can be determined in ERT which involves probes in a setup which runs in actual section.

My recommendation would be having all four tests conducted. These are complimentary to each other and more data can be interpreted with less assumptions. It is essential to have more data in order to assist in proper literature and design philosophy so that information can be use in determining the optimum design within project cost limit. Ground probe radar can be use but it is not as accurate as ERT and much suitable for utility detection works.

If you need any geophysics work in Sabah for construction work, kindly message me for more information and proforma.

Remark: The photo below indicates a section of ERT which me and my associate worked on for slope construction. A professional engineer and a professional geologist is a must when interpreting result and experimental test simulation through modelling. The other one is a photo of ERT setup for risk assessment studies on 3 dams.