Pipe bedding shall be placed as per construction drawing with materials complying with the requirements. Water level in the trench shall be kept to a minimum while placing the bedding material. Bedding shall be levelled and compacted to achieve the required level of compaction. Required bedding angle shall be provided by using hand tools.
The backfill material shall be compacted with plate compactor/compacting rammer. Soil thickness of each layer shall be 150mm maximum at loose stage.
Soil shall not be dumped directly on the pipe. Protective timber board shall be provided to cover the pipe to avoid damaging it due to the soil dump. Uncompacted/ partially compacted soil remaining in previously placed layers shall be moved to adjoin fill and compact. Hand compaction shall be applied in stages to compact pipe surrounding as well as a reasonable height above the pipe crown as per the manufacturer’s recommendation (if required).
BACKFILLING THE REMAINING PART
Maximum depth of each uncompacted soil layer shall not be exceeded 200mm and the number of passes shall be eight. Compaction tests shall be done and the test results shall be available at the site office.
REMOVING OF TRENCH SUPPORT
Removing of trench support shall be done simultaneously with the backfilling. Lowest bracing shall be removed once completed the backfilling up to that level. So on for bracing for higher levels.
The Contractor shall be responsible for removing all the supporting systems that are used for the pipe laying process.