Flexible pipes require the support of the bedding and surround material to transfer dead and live loads to the native soil adjacent to the pipe.

This section provides guidance on the selection of materials suitable for providing structural support to WEHOLITE pipes. Materials which fulfil this role are termed bedding and surround materials. The section deals both with imported granular materials and materials excavated in the course of the works (selected as dug) which are deemed suitable. All WEHOLITE pipes require adequate structural support to ensure their long term performance. The diagrams below show two typical trench configurations and illustrate some of the terminology adopted in pipe design.

Shallow trench bedding and backfill details

Standard Bedding and Backfill, Multi-leg

Deep trench bedding and backfill details

Standard Bedding and Backfill, Single-leg

Minimum recommended working space