Soil Conditioning and Lubrication for Tunnelling, Pipe Jacking and Micro-Tunnelling in Clay Soils

摘要

The application of soil conditioning and lubrication to tunnelling, pipe jacking and micro-tunnelling can significantly improve these construction processes. Lubrication of pipe jacking is achieved by injecting lubricant fluids around the pipe-soil interface to stabilise the tunnel bore and reduce frictional resistance on the pipes during jacking, allowing longer drives to be performed. However, in clay soils lubrication of pipe jacking can be counterproductive by causing accelerated swelling of the excavated bore, increasing pipe-soil interactions and the required jacking forces. The addition of suitable inhibiting agents to lubricant fluids can suppress swelling of the ground to allow effective lubrication; however, uncertainties remain regarding the most suitable agents to use in different ground conditions.