Test pits and/or trenches as distinct Observation supports from Boreholes?

[mbeaufils]

Following

Include options for different sample methods, but don’t lump them all together. Boreholes are different than test pits or trenches and should be captured differently to understand their full meaning.

Need for a specific test pit and/or a trench concept for #12 ?

Originally posted by @AC107 in https://github.com/opengeospatial/Geotech/issues/10#issuecomment-1051051451

[mbeaufils]

A proposed definition discussed in IFC GeoSubgroup:

Trial Pit : An excavation made for the purpose of observing shallow subsurface conditions, performing field tests and obtaining soil samples.

[neilchadwick-dg]

See my comments under issue #10

[IHalfon]

"Test pits/trial pits" should be distinct from "boreholes". They are different exploration hole methods, for different applications.

[Didymograptus]

Are we defining ground models or activities and objects of ground investigations? The two things are very different.

[j-weil]

Agreed that there is a range of ways to collect insight to ground conditions from artificial outcrops, from boreholes over trial pits (being documented more or less detailed) over trenches and adits to investigation galleries and tunnels. And I agree with the comment by Didymograptus] We need to distinguish between a concept for data model and activities & investigation methods. IFC Tunnel's recent concept covered two ends:

1. “Borehole” for linear structures, including soundings. This could cover a trial pit where a simple soil profile with single values for top and bottom depth of layers was logged. “Borehole” is intuitive to and fits most aspects, but may be not the correct term for such a global understanding. On the other hand, abstract terms like “Linear observation support” etc. are not intuitive and raise other problems, as Neil noted.
2. The concept of “mapped zones” where observations with a more detailed geometry can be attached. This could cover any kind of outcrop (natural or artificial) where the outcrop surface of a certain material, discontinuities,… is documented. We listed e.g. FieldOutcrop, TunnelFace, TunnelWall, SlopeArea,… and a more detailed documentation of the wall of a trial pit or trench fits here perfectly

[mbeaufils]

@j-weil As I understand the proposal would be to say that a trial pit can be either assimilated as :

• a tiny-borehole (not so narrow, yet reduced as a line),
• or one or multiples trench walls (and so MappedZones). Am I correct?

[j-weil]

@mbeaufils Correct. The important point is what the type of information is: A linear profile is a very common way to log a test pit, so it can be modelled in the same way as a borehole. More detailed wall-mapping or sketches can be represented by MappedZone (trench wall(s) ) with MappedUnits (different layers), DiscontinuitySurfaces and-Sets and other Observations.