 The triaxial test can be used to determine the shear strength of a discontinuity.A homogeneous and isotropic sample fails due to shear stresses in the sample.If a sample with a discontinuity is orientated such that the discontinuity is about parallel to the plane in which maximum shear stress will be developed during the test, the sample will fail due to shear displacement along the discontinuity, and hence, the shear strength of a discontinuity can be calculated.