BlueLine II Tank DORW2046a 26.08.2013 4 / 16
1.4 Hillside situation
The soil of the area has to be checked for possible soil movement (DIN 1054 edition
1/2003, E DIN 4084 edition 11/2002) and if necessary it will need to be secured with a
supporting structure (e.g. a wall). Further information is available at the local public
authorities and building enterprises.
1.5 Further criteria
Existing pipelines, pipes, vegetation as well as other specifics have to be considered, so
that damage or hazards will be avoided. The soil coverage from the tank shoulder (point
4) may not exceed 1.5 m.
2. Installation
2.1
Backfill material
at the tank (backfill, bedding; point 3 figures 3, 4 and 10)
The backfill material has to be well compactable and permeable to water, allowing close
packing and no damage the surface of the tank. If the filling material contains sharp or
sharp-edged components, the wall of the tank has to be protected by a sandy coating.
2.1.1
Sand - gravel mixtures
(SW and GW to German Institute for Standardization
18196 and ENV 1046) are the most favourable filling materials, because they have a
grain line which consists of several grain sizes with only a low amount of fines (fines:
under Ø 0,06mm). At the description of the mixtures the first number gives the mesh
width (simplified Ø) of the smallest grain and the second one those of the biggest grain:
e.g., 0/32; 2/16; 2/8; 2/32; 4/16. Which mixtures are available, strongly depends on the
regional gravel plants.
2.1.2 Concrete gravel, or treated concrete rubble,
with a particle size of 0/32 mm is
particularly well suited for use in clay/loam soil conditions with ground water and a high
water table. When ground water and a high water table are present, it is particularly
important to ensure good compaction, especially at hard to reach places.
2.1.3
Stone Chippings
- crushed rock particles between 2/32 mm in size and is
primarily suited as a filling material; however due to its sharp edges, the tank must be
protected against damage, for example using a sand coating.
2.1.4
Excavation, sand and gravel mixture with mixed particle sizes
is suitable for
use as a filling material when it meets the criteria listed under Item 2.1.
2.1.5
Top soil, clay, loam and other types of cohesive soils
are not suitable filling
materials.
2.2
Filling beyond the backfill
Excavated soil (point 3 figures 1 and 10) or other material can be used if this is stable
and permeable.
2.3 Backfilling and compaction methods
2.3.1 The backfilling and compaction methods to be used
are described in Section
3 (Installation instructions)
2.3.2 Methods that are not to be used
include in particular adding water. Adequate
compaction is not achieved and the mixture of particle sizes combine in such a way that
the compaction is unstable.
2.3.3 Base layer (driveable version)
Range of grain size 2/45 is to be used.
