The Torshear machine is dedicated to the determination of the residual shear strength. The residual shear strength of soils is sometimes also termed the ultimate shear strength. This is the strength of soil when it is sheared to large displacements, for example along the failure plane of a landslide or in a fault zone. A remoulded specimen is used to determine the residual shear properties of the soil. A slip surface is formed in the test specimen as part of the test procedure. It can also be useful to know what sort of value the residual shear strength of an intact soil can have, because this (when taken in conjunction with the peak shear strength of the same soil) indicates its brittleness or susceptibility to progressive failure