Assertion: trench's depth | /r/CapableOf | extend through pervious soil layer
Facets:
value: preferably
type: MANNER
value: into the impervious layer
type: TRANSITIVE-OBJECT
Source sentences:
text: from 0.5 m in small dikes to at least 1 m in larger dikes; depth of the trench: preferably extending through the pervious soil layer into the impervious layer beneath.