Instruments and methods for soil testing in the conditions of constrained dilatancy
This chapter dwells on the construction of special instruments designed for shear and triaxial tests. In the process of designing an attempt was made to widen the range of their possibilities and avoid errors which may appear due to an inadequate reflection of natural conditions of soil deformation and failure. The Dilatometric Apparatus of Contact Shear (Dacs) is defended by a USSR copyright, certificate 1491143 under the name ‘Apparatus for measuring contact resistance to shear of dry materials’. Two modifications of the instrument were manufactured, namely: DACS-1 and DACS-2. The DACS-2 instrument is distinguished by a symmetric arrangement of rests and dynamometers on both sides of the carriage. Instruments DACS-1 and DACS-2 ensure step-by-step application of the shearing force, which allows to model conditions of gradual loading of a construction in soil.