DiscreteDiscontinuity

What is a DiscreteDiscontinuity?

Any interuption of the continuity in the rock material with its attendant mechanical, hydraulic and thermal properties.

Realizations

Data model	Concept name	Definition
IFC	DiscreteDiscontinuity	Any interuption of the continuity in the rock material with its attendant mechanical, hydraulic and thermal properties.
OGC GeosciML	Joint	Fracture across which there is no displacement at the scale of interest.
DIGGS	DiscontinuityObservation	Descriptions of faults, fractures and joints and their spacing, with attendant mechanical and hydraulic properties.

Properties

Property name	Definition
DiscontinuityType	pattern of bedding, folds, faults and discontinuities in rock masses, which subdivide the mass into individual domains or rock blocks (ISO14689)
DipDirection	The azimuth of the dip (dip direction) shall be measured in degrees in the range 0° to 360° counted clockwise from true north and expressed as a three-digit number, e.g. 240 or 015. (ISO14689)
DipAngle	The maximum declination (dip) of the mean plane of the discontinuity from the horizontal shall be measured with the clinometer in the range 0° to 90° and should be expressed in degrees as a two-digit number, e.g. 50. (ISO14689)
DiscontinuitySpacing	The term “spacing” refers to the mean or modal spacing of a set of discontinuities and is the perpendicular distance between adjacent discontinuities. The number of discontinuity sets, the differences in spacing and the angles between the sets shall be reported as these determine the block shape. The discontinuity spacing should be measured in millimetres and can be classified using the terms in Table 8. (ISO14689)
DiscontinuityPersistence	The linear extent of discontinuities from their inception to their termination in solid rock mass or against other discontinuities or outside the exposure shall be reported. The size of the exposure shall also be recorded. If possible and appropriate, measurements should be made in two or preferably three orthogonal directions. (ISO14689)
DiscontinuityRoughness	The surface condition and the shape of discontinuities shall be described on the basis of three scales of observation, respectively, and using the terms given in Table 9 and illustrated in Figure 2: a) small scale (several millimetres) — smooth or rough; b) medium scale (several centimetres) — planar, stepped or undulating; c) large scale (several metres) — straight, curved or wavy. (ISO14689)
DiscontinuityAperture	The perpendicular distance between the two surfaces of a discontinuity is referred to as the aperture. (ISO14689)
DiscontinuityInfilling	The infilling material between discontinuity surfaces shall be identified and described (e.g. soil,minerals such as calcite, quartz, epidote, chlorite, anhydrite, clay gouge, rock gouge or breccia). (ISO14689)
DiscontinuityWaterSeepage	Free moisture or water flow visible at individual spots or from discontinuities
Cohesion	Cohesive shear strength of a rock or soil that is independent of interparticle friction.
FrictionAngle	Derived from the Mohr-Coulomb failure criterion and used to describe the friction shear resistance of ground materials, together with the normal effective stress.

FAQ

How to deal with DiscontinuitySets in a GeotechnicalUnit?

A description of the sets of discontinuities can be described as properties of a GeotechnicalUnit.

GitHub issue

https://github.com/opengeospatial/Geotech/issues/23