Study on short and "long term" effects of chemicals on fine grained soils for mechanized tunnelling conditioning

This study presents the preliminary results of research activity focused on the physical and mechanical properties of soil treated with the injection of chemicals, commonly used in tunnelling performed with tunnel boring machines (TBMs) and EPB technology. For fine grained soils, the focus is to enhance the excavation process, optimizing consistency as well as reducing adhesiveness and clogging. Moreover, a study of the mechanical properties of the conditioned soil, relevant for the project of spoil disposal and reuse. Common tests and other specifically designed geotechnical tests were performed on different samples of two clayey soils. These were treated using different foams generated by the three most used foaming products. Results provide insight into the effectiveness of the chemicals tested to reduce clogging potential and on the mechanical properties of the treated soil useful for soil reuse.