A More Comprehensive Way to Analyze Foam Stability for EPB Tunnelling—Introduction of a Mathematical Characterization

In the tunnelling industry, a large share of market is occupied by EPB (Earth Pressure Balance) machines. To operate this kind machine, radical change in rheological behaviour excavated soil must be performed, and achieved adding water, foam, and, eventually, polymers. The stability foam assessed through half-life test. main limitation test that only one value used characterization degradation process, which insufficient to describe whole evolution phenomenon. results more than 270 tests were modelled five-parameter mathematical formulation suited experimental data. show influence concentration on not always present flow rate during production bears an characteristics foam.