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Persistence determines the possibilities of relative movement along a discontinuity in a soil or rock mass in
{{Cite book
, last1 = ISRM
, author-link = ISRM
, year = 1981
, title = Rock Characterization, Testing and Monitoring, ISRM suggested methods
, editor1-last = Brown , editor1-first = E.T.
, publisher =
Soil mechanics
Rock mass classification
Persistence determines the possibilities of relative movement along a discontinuity in a soil or rock mass in geotechnical engineering
Geotechnical engineering is the branch of civil engineering concerned with the engineering behavior of earth materials. It uses the principles of soil mechanics and rock mechanics for the solution of its respective engineering problems. It a ...
. Discontinuities are usually differentiated in persistent, non-persistent, and abutting discontinuities (figure).
Persistent discontinuity
A ''persistent discontinuity'' is a continuous plane in a soil or rock mass. Shear displacement takes place if the shear stress along the discontinuity plane exceeds the shear strength of the discontinuity plane.Non-persistent discontinuity
A ''non-persistent discontinuity'' ends in intact soil or rock. Before movement of the material on both sides of a non-persistent discontinuity is possible, the discontinuity has to extend and break through intact material. As intact material has virtually always far higher shear strength than the discontinuity, a non-persistent discontinuity will have larger shear strength than a persistent discontinuity.Abutting discontinuity
An ''abutting discontinuity'' abuts against another discontinuity. Abutting discontinuities might continue at the other side of the intersecting discontinuity, however, with a displacement to give so-called ‘stepped planes’. Shear displacement along the discontinuity can take place if the shear strength along the discontinuity plane is exceeded, and the blocks of material against which the discontinuity abuts can move or break.Anisotropic persistence
A discontinuity might be persistent in dip direction but be not persistent perpendicular to the dip direction or vice versa.See also
* Discontinuity (geotechnical engineering) *Rock mechanics Rock mechanics is a theoretical and applied science of the mechanical behavior of rock and rock masses; compared to geology, it is that branch of mechanics concerned with the response of rock and rock masses to the force fields of their physical env ...
* Shear strength (discontinuity)
References
Pergamon Press
Pergamon Press was an Oxford-based publishing house, founded by Paul Rosbaud and Robert Maxwell, that published scientific and medical books and journals. Originally called Butterworth-Springer, it is now an imprint of Elsevier.
History
The c ...
, Oxford
, pages = 211