Creating the upper bedding layer
- Raise the lower edge of the shoring to the installation height.
- Use backfill material and layer thickness as specified by the construction manager/foreperson.
- Be sure the backfill material is free of stones and foreign substances/objects (e.g. wood, waste, topsoil).
Creating the upper bedding layer
Install backfill material on either side of the pipe across the width of the working area and over the length of the trench section, and then distribute it evenly.
Key
- 1. Upper bedding layer – haunch area beneath pipe
- 2. Upper bedding layer – area to the sides of pipe
- 3. Lower bedding layer
- 4. Base of pipe
- In the haunch area 1, insert the backfill material under the pipe by hand and compact it according to the instructions of the construction manager/foreperson.
- Suitable equipment must be used to compact the backfill material in the haunch area beneath the pipe, according to the instructions of the foreperson – e.g. bending bar, hydraulic spade, tamper.
- The compaction of the haunch area (upper bedding layer) must be at least as good as the compaction of the lower bedding layer.
Creating the upper bedding layer
- Install backfill material on either side of the pipe across the width of the working area and over the length of the trench section, and then distribute it evenly.
- The areas on both sides of the pipe (upper bedding layer) must be built up and compacted evenly.
- Lightweight pipes must be secured (e.g. using rebar) before compaction to prevent them from shifting out of position.
- After the compaction of the haunch area, compact the upper bedding layer on both sides of the pipe using a lightweight compacting device (as specified by the foreperson).
- Compact the backfill material in multiple passes, with the force directed towards the in-situ soil of the trench wall.
- Ensure that the upper bedding layer and the compaction in the haunch area are at the correct height.