The factors controlling the expansive nature of the soils and rocks of northern Oman

The factors controlling the expansive nature of the soils and rocks in Northern Oman were studied. Basic geotechnical data from over 40 sites were collected and using empirical relationships, swelling potentials were identified. A laboratory testing program was carried out using undisturbed samples from these swell pressures up to 3.5 MPa, and swell percent values up to 30 were measured. The clay minerals and cations of these samples were determined and Na-smectite was identified as being the main clay-mineral present. Microfabric studies showed generally dense clay matrices. However, these swelling materials exist as impersistent bands with non-swelling soils and rocks which makes prediction of the ground heave problematic.