Electric imaging (EI) of soft clay deposits in some east and southeast asian deltas

摘要

A great amount of construction and infrastructure projects in Asia are carried out on thick deltaicrnsoft clay deposits, whose geotechnical characteristics might often be poorly investigated due to not onlyrnmethods of investigation but also the easy disturbance of soft clays. For projects covering large areas such asrnthose of highway construction or reclamation a fast and reliable investigation tool is particularly needed. Withrnrecent development of the electric imaging technique the weak electric signal in soft clay deposits can be betterrnacquired by modern resistivimeters. Investigations that the author had conducted over the last ten years forrndifferent clays in some East and Southeast Asian deltas such as the Busan clay in the Nakdong River plainrn(Korea), the Bangkok clay in the Chao Phraya plain (Thailand), the Red River delta clay and the Mekong deltarnclay (Vietnam) proved the electric imaging method can be a fast and good tool to aid the conventional geotechnicalrnsite investigation of natural and improved clay deposits. The electric imaging results can separaternquite well a soft clay layer from medium and stiff clay and sand layers in a deltaic sequence. This paper willrnpresent concisely fundamental of resistivity method and the procedure to perform electric resistivity measurementsrnin the laboratory and field conditions as well as the results obtained from some case studies of therndeltas mentioned above.