A new failure criterion was presented to predict the ultimate strength of shale under the triaxial and polyaxial state of stress. A database containing 93 datasets was obtained from the results of the uniaxial, triaxial, polyaxial compressive tests, an indirect tensile test was collected from reliable references, and this test was carried out on the shale samples taken from the southwestern oil...

Wellbore stability analysis based on a new true-triaxial failure criterion i Abstract A main aspect of wellbore stability analysis is the selection of an appropriate rock failure criterion. The most commonly used criterion for brittle failure of rocks is the Mohr-Coulomb criterion. This criterion involves only the maximum and minimum principal stresses, σ 1 and σ 3 , and therefore assumes that ...

With the construction of supertall buildings such as high earth dams, linear envelope Mohr-Coulomb (M-C) failure criterion fitted to lower confined pressure would significantly underestimate loading capacity foundations, causing a huge increase in amount earthwork. Given that M-C has dominated stability analysis geotechnical structures, it is proposed this study remain invariant form but cohesi...

wellbore instability is a quite common event during drilling, and causes many problems such as stuck pipe and lost circulation. it is primarily due to the inadequate understanding of the rock properties, pore pressure, and earth stress environment prior to well construction. this study aims to use the existing relevant logs, drilling, and other data from offset wells to construct a precise mech...

Abstract Extension fractures are typical for the deformation under low or no confining pressure. They can be explained by a phenomenological extension strain failure criterion. In past, simple empirical criterion fracture initiation in brittle rock has been developed. this article, it is shown that makes unrealistic strength predictions biaxial compression and tension. To overcome major limitat...

A new method for implicit integration of the Mohr-Coulomb non-smooth multisurface plasticity models is presented, and Koiter’s requirements are incorporated exactly within proposed algorithm. Algorithmic numerical complexities identified introduced by nonsmooth intersections surfaces; then, a projection contraction algorithm applied to solve classical Kuhn–Tucker complementary equations which p...

A finite element program based on elastic –plastic model of Mohr-Coulomb criterion was used to evaluate the bearing capacity coefficients of soil under shallow strip flexible footing . The results were compared with others’ analytical results and it was found that the present study could offer quite consistent and rather precise values for the bearing capacity coefficients . &#10&#10The effect ...