Stiffness and strength of an artificially cemented sand cured under stress

Abstract

Research on naturally cemented soils (e.g. sandstones) has increased considerably in recent years, mainly due to the growing interest in finding new offshore oil wells at depths that can sometimes exceed 1000 m. Although testing using undisturbed samples is ideal, the extraction, transport and preservation of such samples is incredibly difficult and sometimes unfeasible. Therefore, in order to study the natural cementation of these materials, triaxial compression tests were performed on an artificially cemented sand cured at effective stress of 500, 2000 and 4000 kPa and then compared with samples cured under atmospheric pressure and then sheared at the same effective stresses. Samples with different dosages were studied. Results showed that the type of curing does not present statistical influence on the peak strength values. On the other hand, the type of curing, together with the effective stress at the beginning of the shearing and the sample dosage control both the maximum stiffness values at very small strains as well as the stiffness degradation with strain. Simple mathematical models have been successfully adjusted to standardized results.