Investigation on the geotechnical properties of a chemically conditioned spoil from EPB excavation, a case study

The management of the spoil from a high-speed railway tunnel to be constructed with EPB technology required the geotechnical characterization of the conditioned soil after excavation. This paper describes the laboratory characterization of the two lithotypes that should be en-countered more extensively by the EPB-TBM, before and after conditioning. The influence of chemicals on the geotechnical properties of the conditioned soil was investigated by simulating the conditions that muck will experience during its temporary stock on site ("ageing"), to meet environmental and geotechnical requirements for its re-use. The evolution of the index proper-ties, the compactability and the shear strength was followed with measurements at 0, 7, 14 and 28 days (end of ageing) after the injection. In Author's knowledge this experimentation is the first attempt in Italy to characterize a chemically conditioned spoil at such extent.