Light crude oil

Shear modulus

Ecology

Biology

Geotechnical engineering

Materials science

Shear (geology)

Petroleum engineering

Triaxial shear test

Overburden pressure

Geology

Soil water

Cohesion (chemistry)

Paleontology

Organic chemistry

Contamination

Soil science

Composite material

Compaction

Chemistry

Crude oil

Hydrocarbon

Modulus

European Journal of Environmental and Civil engineering

The geotechnical properties of hydrocarbon-contaminated soils have been greatly concentrated so far due to its effectiveness and significance in various aspects of engineering applications. In this regard, several hydrocarbon contaminants and diverse soil types were considered in the literature aiming at evaluating physical, chemical and engineering characteristics of hydrocarbon-contaminated soils including particle size, hydraulic conductivity, compaction and compressibility, internal friction and cohesion as well as shear strength. Meanwhile, small-strain shear modulus of hydrocarbon-contaminated soils (Gmax or G0) has not been precisely focused. In this paper, bender element (BE) test was employed to examine the effects of a hydrocarbon (light crude oil) on shear wave velocity and the resultant Gmax of Iranian silica sand, Firoozkooh sand. In this connection, various methods of determining shear wave travel time in BE test were firstly evaluated, and the most reliable ones (start-to-start method and cross-correlation function) were employed to analyse the results. The values of Gmax were found highly sensitive to crude oil contamination and confining pressure so that Gmax increased after uniformly mixing oven-dried sand with 4 wt.% of crude oil under various confining pressure; however, the degree of induced changes diminished as confining pressure grew. Moreover, adding more crude oil up to 8 wt.% substantially decreased the value of Gmax to an amount slightly higher than that of the clean sand. Beyond this oil content (≥8 wt.%), Gmax followed a status of scattering and there was not significant alteration to be cited. The analytical results obtained by BE test about the hydrocarbon-induced alteration on Gmax could be confirmed by the microstructure observations via scanning electron microscopy.

Effects of light crude oil contamination on small-strain shear modulus of Firoozkooh sand