ABSTRACT
A physical simulator has been developed by BOUYGUES TRAVAUX PUBLICS and SIKA as the first device to carry out innovative tests for soil conditioning additives under operation pressure and as a reliable tool to evaluate its performance and dosage. The outputs, conclusions and information provided by these tests lead to energy savings, cost reduction and environmentally friendly solutions for Earth Pressure Balanced tunnel boring machines close to working hyperbaric conditions. Up to now, the rheology was only tested in atmospheric conditions. Five representative types of soil have been selected with different additives and pressures in order to represent most significant ground conditions met on construction sites. In order to find out the optimal dosages, several reference tests have been specifically defined for soil behavior characterization. The following tests are included:
– Classical tests as slump test, density measurement … – New ones as conveyor test for measuring the paste flow on the rubber band,
baroïd test for determining the soil permeability under hyperbaric conditions, screw conveyor for simulating the paste extraction, torque measurement.
