|  | Pipe Jacking, Caissons, and Structure Jacking Note: This page deals with annulus lubrication. Regarding tunnelling methods which use additives, please click on slurry or epb/pumped muck. What causes high jacking load? When setting up for success on a difficult pipe jack it's worth considering how the ground conditions can affect overall friction.
Herrenknecht AVN jacking system
| Bentonite as a lubricant Standard grade bentonite is adequate for use in stable, clay-free ground. Its performance is dramatically improved by:
Clay stickiness and swelling Clay (bentonite) based lubricants can be of limited use in swelling clay. Consider a specialist additive such as TK60 Jacking Lubricant which actively prevent clay from swelling and contain powerful polymeric lubricants. Loss of Lubricant to the Ground Preventing lubricant loss to the ground can make all the difference. Choose Sloop or FibrouSeal to help maintain the annulus. These products can be added to your existing bentonite lubricant or used in a pure polymer mix. Gravels, Sands and Silts Falling into Annulus Counteract this by adding MX Polymer to the mix. MX has a powerful sand and gravel stabilizing effect. Annulus Maintaining lubrication for Caissons Similar problems can affect caisson lubrication, with the additional risk of losing lubricant if you have to underpin. Morrison Mud's Annulus Maintaining concept provides lubricants which hang and do not flow out catastrophically in the event of a leak. The Sloop system is the most often used - and we can provide special formulations on request. Salt water lubricants Most standard annular lubricants are ineffective in salt water. For best performance we recommend MX Polymer. This material is particularly effective in holding back slump loading of gravels and sands on to the pipe.
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