Determination of non-linear shear strength and volume changes on remolded granitic residual soil due to membrane penetration

Abstract

Membrane penetration is the term used to describe the displacement of the rubber membrane into the spaces between the cylindrical specimens during triaxial testing in the consolidation stage. Membrane penetration from elevated cell pressure during the consolidation stage might have a negative effect on the interpretation of stress-strain data and specimen volume calculations during the shearing stage. To assist engineers in making knowledgeable judgments, additional study is needed to examine membrane penetration in granitic residual soil. In this study, membrane penetration was investigated using a modified graphical technique. Triaxial tests on grade V granitic residual soil were conducted as part of the study at effective confining pressures of 50 kPa, 100 kPa, 200 kPa, 300 kPa, and 400 kPa. In the tests, real specimens constructed of compacted granitic residual soil with initial diameters of 50mm and 100mm, and dummy specimens made of a thin soil layer containing a solid, rigid cylindrical core, were both employed. Without considering the impact of specimen compression, the behaviour of membrane penetration was only examined in the dummy specimens. The graphical method has to be altered as a result of the fines. The findings demonstrated that the effect of membrane penetration increased with a rise in effective confining pressure and became less relevant at confining pressures of 300 kPa or lower.