English (GB)
8
4.5 Uplift prevention
The pit design ensures that the pit is protected against uplift if
installed correctly. Requirements for uplift prevention depend on
the geotechnical conditions. They should be determined by the
engineer or contractor and are outside Grundfos' area of
responsibility.
The safety against uplift is determined according to Eurocode EN
1997-1 including national annex, DS/EN 1997-1 DK NA:2015.
The most unfavourable ground water conditions for the pit is
when the ground water table is located at terrain level. This
situation creates the highest hydrostatic water pressure at the
bottom of the pit, and causes the highest reduction in soil weight
for the stabilising soil volume.
The sand volume resting on the shoulder of the pit is a stabilising
force. The sand volume is determined as a cone with hollow core
as illustrated in fig.
.
The inclination of the cone is illustrated 1:n. The inclination n can
be determined based on the friction angle for the design. The
characteristic friction angle for sand with a unit weight of 19 kN/
m
3
, compacted to 97 % standard proctor, is estimated to 37
degrees. The design friction angle is 32 degrees which
corresponds to an inclination of n = 1.6.
Fig. 9
Stabilising sand volume
4.6 Connecting the pipes
Holes for inlet pipe, electrical connection and venting are to be
drilled on site.
1. Mark the pit where the inlet is to be.
2. Drill the marked spot with a hole saw.
3. Remove all burrs from the hole.
4.6.1 Drilling the inlets
Figures
show which hole saw to use for the various
pumping station diameters, depending on the difference in the
wall thickness.
Fig. 10
Wall profile PS.W.04-10
Fig. 11
Wall profile PS.W.20
The requirements below are minimum requirements.
Observe local regulations.
TM0
6
7
26
9 2
3
1
6
We recommend that you provide the pit with a vent
pipe, supplied as an accessory.
Place inlet and outlet pipe connections in accordance
with local regulations.
PS.W.04 - PS.W.10
Diameter
[mm]
Wall thickness - A
[mm]
400
30
600
44
800
57
1000
72
TM
06
36
0
5
13
17
PS.W.20
Wall thickness varies for SN2 and SN4
Diameter [mm]
SN2 [mm]
SN4 [mm]
2000
Minimum 84
Minimum 114.5
TM
06
36
1
0
06
15
X
Summary of Contents for PS.W.04
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