Model tests have been performed to investigate the behaviour of a sand-water-foam mixture. A TBM with an earth pressure balance shield was simulated. Saturated sand was mixed with foam and the sand-water-foam mixture was removed with a screw conveyor. The properties of the mixture in the 'mixing chamber' and in the screw conveyor have been studied. Two different sands where tested with a d_(50) of 135μm and 300μm respectively and two different foams. Changing the sand had a significant influence on the result. The influence of the type of foam was less.
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