Rotslengte

Rotslengte is a Dutch term used in geology and geotechnical engineering to describe the linear length of a rock exposure or rock segment along a defined direction. The concept helps quantify the size of rock units encountered in mapping, drilling, and excavation, and it can influence estimates of rock volume, stability assessments, and construction planning. The typical unit is meter, though decimeter or centimeter precision may be used in detailed fieldwork.

In practice, rotslengte may refer to different specific measures depending on context:

- the length of a continuous rock body along a face or outcrop

- the distance between major discontinuities along a survey line

- the length of rock remaining behind a tunnel face

Measurement is done with tape measures, laser rangefinders, total stations, or 3D scanning; data are often recorded on geological maps or in borehole logs.

Rotslengte is affected by geological processes such as weathering, fracture development, and tectonic deformation, and can vary over short distances. It is distinct from rock thickness (the dimension perpendicular to the plane of interest) and from areal extent (the area covered by a rock unit). In practice, practitioners specify the direction and reference point when reporting a rotslengte. See also outcrop mapping, discontinuity length, and tunnel face geometry.