German to English Tech/Engineering Petroleum Eng/Sci Pipeline construction

Hopefully the last in my long series of terms relating to the pipeline management system.

Appears as an isolated term in a so-called "Mengengerüst":

Objektklasse - Minderdeckung
Außendurchmesser in mm - 419
Rohrwerkstoff - St 34.28

Ergebnis der TZA-Auswertung (whatever this is):
Überdeckung (m) (MIN) = 0,00,
Bodennutzung = Wald,
Überdeckung (m) (MAX) = 0,20,
Auftriebsgefahr = ja, Auftriebssicherung = unbekannt

I wonder whether it might be something like "inadequate cover", but would again appreciate some help.

At this point I'd like to express my thanks to all of you who have helped so far with this exceptionally long list of terms.