A note on the lade–duncan failure criterion

The non-linear relationship between the internal frictional angle (Formula presented.) and the first stress tensor invariant (Formula presented.), together with the cohesion c of geomaterial, is used to show that the Lade–Duncan failure criterion is a more general failure criterion with a deep physical meaning. It can be used to describe the strength failure characteristics of sand and normally consolidated soil mass as well as those of cemented geomaterials. As demonstrated for (Formula presented.) on (Formula presented.) planes, the Lade–Duncan failure criterion reveals the basic mechanical deformation characteristics for geomaterials. The test results for red sandstone indicate that the differences between the internal frictional angles in the triaxial extension and compression states on (Formula presented.) planes will be reduced as the average principal stress increases.