Applications of Electrical Resistivity Surveys in Solving Selected Geotechnical and Environmental Problems

Abstract

Standard test methods may not be suitable or sufficient for determining the geotechnical conditions of a structure’s subsoil and the effects of the designed structures on the environment. Geophysical test methods, validated with other methods, may prove useful. In recent years they have found many new applications in engineering practice, both geotechnical and environmental. The advantages of geophysical methods include the non-destructive and non-invasive nature of the tests, their low costs and quick results, as well as compatibility with different materials, including soils, solid rocks, wastes and anthropogenic formations. The paper presents the analysis of laboratory and field investigations including research in a modified oedometer, resistivity chamber, electrical resistivity tomography (ERT) and resistivity cone penetration test (RCPT). Laboratory tests allowed for the assessment of the degree of saturation and porosity of sandy and clayey soils. The tests were carried out on saturated and unsaturated soil samples and allowed for the determination of some relationships between electrical conductivity and porosity. The proposed equations were used to assess parameters in in situ studies using RCPT tests and showed good agreement with reference values based on undisturbed soil samples. ERT tests confirmed the usefulness of electrical measurements in the quality assurance of subsoil and hydrotechnical structures. The tests showed weakening zones in the levee body, discontinuity of the vertical sealing system on the modernized section of the embankment, and location of the top of clay deposits.