Laboratory Testing of Soil Conditioning and Lubrication Methods

This phase of the work started in October 1998.

Sotirios Psomas is a research student at Oxford University, supported by the Pipe Jacking Research Group to work on this project. The project is supervised by Prof. Guy Houlsby.

The purpose of the project is principally to investigate the performance of soil conditioning agents, used in conjunction with the tunnel-boring machines which are now often used on pipejacks. There will be a wider application of the research to other tunnelling applications.

Soil conditioning methods are used to improve the cutting and flow characteristics of the soil, so that it can be handled more efficiently by the machine. In some materials the purpose is to improve performance of the machine, but in others the conditioning agents may be used to make tunnelling possible where it would otherwise have been impossible.

A variety of materials are used for soil conditioning purposes, but probably the most promising at present are foams.

Simple laboratory tests are to be carried out in which the effects of the conditioning agents on soils will be measured. The first phase will involve measuring the reduction in power requirement to mix the soil as the conditioning agent is added. More sophisticated testing will follow, and in due course it is hoped that a standard method of testing the properties of a soil and conditioning combination will be devised.