The challenge: Putting the pipes to bed

摘要

When a drainage pipeline is buried in the ground, loads are transferred between the pipe and the surrounding earth by the bedding surrounding the pipe. There are three main types of loads that apply: the weight of the overlying trench-fill, pressures transmitted to the pipe from surface loads such as traffic, and the supporting reaction from the ground beneath the pipe. In addition, for larger diameter pipes the load imposed by water in the pipe may also need to be considered. There are various bedding solutions or Classes described in British Standard 9295: Guide to the Structural Design of Buried Pipelines. The most significant differences between bedding Classes is the extent of the area around the pipe where the granular bedding material is placed. Class S bedding, for example, requires a pipe to be completely surrounded by granular material. Other Classes, such as B, F and N require significantly less granular material.