A STUDY OF THE PROPAGATION OF TECTONIC DISLOCATIONS IN CLAY
The propagation of a shear band may take place in clay deposits due to development of tectonic dislocations in the bedrock. The conditions under which this phenomenon actually develops are little known. This report presents a state of the art either on the clay constitutive laws or on the shear bands in generic geological conditions. In its first part basic mathematical models concerning rock mechanical behaviour are discussed. In the second part of the report the state of the art on the shear bands is presented. The dislocation is considered as a discontinuity in the originally homogeneous strain field of the infinitesimal element; such discontinuity is the effect of the bifurcation of an equilibrated configuration. This problem is later simplified using an artificial bidimensional medium, called "Schneebeli medium". A criterion defining a critical tangent modulus at which bifurcation occurs and the direction of the discontinuity, is then obtained. It has been found from the review of the technical literature that the criteria given by Rice and Rudnicki, Rice and by Vardoulakis offer a good basis for studying shear band phenomenon. The criteria need however further development, in order to take into account constitutive laws more suitable for clay; the studies concerning the flow rules at the shear bands need further development too. Finally, research trends are indicated.
Bibliographic Reference: EUR 10620 IT (1986) MF, 178 P., BFR 300, BLOW-UP COPY BFR 900, EUROFFICE, LUXEMBOURG, POB 1003
Availability: Can be ordered online
Record Number: 1989125001800 / Last updated on: 1987-01-01
Available languages: it