ABSTRACT
Tunnelling with EPB machines in urban environment, the mucking operation plays a key role for the project success. Often the mucking system made by a horizontal belt cannot be used since the beginning due to the lack of available areas for the whole TBM installation. To face these issues, the contractors can select different mucking techniques as piston pumps and/or vertical belts whose successful application is strictly related to the soil conditioning.
The paper presents the Metro Line 14 lot T2 project in Paris and the mucking solutions designed and applied by the J.V. (Bouygues TP, CSM Bessac, Soetanche-Bachy, Soletanche-Bachy-tunnel) with the cooperation of the MAPEI-UTT technical team.
The combination between a foaming agent and a dispersing agent (at a very low concentration) has been used to generate the foam, enhancing its lubricating properties with several advantages: soil consistency optimal both for the piston pump and the vertical belt.
