Abstract: A tunnel is built in successive sections by a machine suitable for operating at the surface and in immersion that is displaced in the water on the sub-sea soil. This machine includes a fluid-tight working space (6) for accommodating the personnel and equipment required for construction. Further, this space has a rearward-facing opening for building and erecting a section at the rear of the machine. The forward section of the machine includes a ballastable chamber (7) which prepares and grades the soil for erection of a section.

Abstract: The invention relates to a method for informing the operator of a tunnelling machine on physical features of a ground to be tunnelled consisting in placing one or several sensors (1-4) directly on each cutter wheel of a drill head, wherein said sensors are selected such that they are capable of transmitting representative signals of the cutter wheel penetrating force into the ground, a rotating state, the position and the temperature of the cutter wheel and in transmitting said information to the operator of the tunnelling machine. Said invention is particularly suitable for detecting hard rocks during digging an excavation by means of a tunnelling machine.

Abstract: The tunnel is built in successive sections by means of a machine M suitable for operating at the surface and in immersion that is displaced in the water on the sub-sea soil, this machine comprising a fluid-tight working space (6) for accommodating the personnel and equipment required for construction, this space having a rearward-facing opening for building and erecting a section at the rear of the machine and the machine comprising in its forward section a ballastable chamber (7) equipped with means (21-23) for preparing and grading the soil in readiness for erection of a section. Application to construction of a tunnel on the bottom of a body of water.