Filling the pit for the pump chamber with D400 cover installed

Pit filling (with D400 pump chamber cover installed)
Pit filling (with D400 pump chamber cover installed)

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Underlay

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Levelling layer

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Sand/gravel layer without sharp-edged content, grain size: 0...32 mm, max. layer thickness: 300 mm

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Substructure for traffic surface, at least gravel or rubble layer, min. layer thickness: 400 mm, friction angle: >37.5°

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Sand layer, max. grain size: 16 mm, minimum layer thickness: 100 mm

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Load distribution plate

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Concrete adjusting rings for pump chamber extension

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Traffic surface substructure

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Class D400 pump chamber cover

  1. Fill and compact the pit with coarse-grained soil in layers and make sure that each layer is not thicker than 300 mm. Use sand or gravel without sharp edges, with a grain size ranging from 0 ... 32 mm, and apply evenly to keep a equal height up to the base of the substructure. Manually compact (with a shovel, hand rammer) the areas directly next to the pump chamber wall. Make sure that the pump chamber is in a plumb-vertical direction and without deformation. CAUTION! Keep the top sand/gravel layer (compacting layer) at the same height as the cover flange. CAUTION! Obey the local standards to embed, fill and seal the piping.
  2. Install the substructure for the load distribution plate. Follow the same procedure as the substructure for traffic surfaces. Obey the same applicable regulations for the installation of substructure for traffic surfaces. Basic requirements:
    Gravel or rubble layer has a layer thickness of min. 400 mm and a friction angle of >37.5°.
    The substructure, if uneven, has a minimum outer diameter of 2.90 m at the base.
    CAUTION! Make sure to use a protective sand layer (max. grain size: 16 mm) of min.100 mm between the substructure for the load distribution plate and the body of the pump chamber or the pump chamber extension.
  3. Put the load distribution plate centrally.WARNING! Make sure that the load distribution plate has a full-faced contact with the substructure.
  4. If a pump chamber extension with concrete rings is required, now put the concrete rings centrally on the load distribution plate. To make a solid and full-faced contact between the concrete rings and the cover frame, and to prevent water ingress from ground water or surface water, it is necessary to apply a small layer of mortar to the mating surfaces on the concrete rings and the cover frame.
  5. Put the cover flange centrally on the load distribution plate or on the last concrete ring.
  6. Align the surface level, including substructure, with the pump chamber cover.