Compression zone
As a compression zone (also backfill zone ) is used in road construction and civil engineering in Germany acc. ZTVA-StB 97, the space within a conduit trench above the pipe zone to the subgrade below the unbound base course understood. The term is complementary to the line zone .
features
The requirements of ZTVE-StB 94, version 97, apply to the degree of compaction to be achieved in the area of the pipeline zone and in the rest of the trench area . The pipeline and compaction zone can be compacted properly if the standards, in particular DIN 4124 and the accident prevention regulations (UVV) prescribed minimum trench widths are observed and compaction takes place in layers . Cohesive soils are not suitable for compaction and must be replaced ( soil replacement ). As a rule, class V1 soil should be used for the compaction zone, as it is easier to compact than class V2 and V3 soils due to its lower sensitivity to water and therefore weather conditions. The compression classes result from DIN 18196.
If the values for the degree of compaction prescribed in the ZTVE-StB cannot be achieved because, for example, the density of the soil surrounding the pipe trench does not allow this, at least the degree of compaction of the soil in the compaction zone must reach the level of compaction of the surrounding soil up to the upper edge of the subgrade .