Geotechnical studies for the Kelian River diversion project, Indonesia

The site investigation program for the proposed Kelian River diversion adopted an integrated approach between mapping, drilling and geophysical studies to overcome difficult site conditions. This allowed optimisation of data along the three alternate open channel routes and at depth to the channel invert level. A total of 26 boreholes, 1466m of drilling and 3400m of seismic refraction survey was carried out. Geotechnical data was presented as summary logs on geological sections to provide suitable models for design studies. Channel slope design adopted a “mine geotechnics” approach to maximise overall slope angles and reduce costs within an acceptable degree of risk commensurate with a civil engineering structure. Physical and geotechnical criteria were used to provide guidelines for final selection of the channel route.