ABSTRACT
Laboratory investigations of lubrication and soil conditioning for pipejacking and tunnelling in clay soils are reported. Lubricant fluids for pipe jacks through clay often include agents to inhibit swelling of the ground to achieve effective lubrication and reduce jacking forces. The effects of various inhibiting agents on the swelling of three clays have been measured, covering a range of clay soil properties. Soil conditioning agents are often used during tunnelling with earth pressure balance machines to improve their performance in excavating clays. Laboratory tests are described investigating the effects of conditioning agents on the properties of clay soils and machine-soil interactions with an experimental model screw conveyor system.
