For some projects , particulary dam cut offs , the hydrofraise has to go down as deep as 100 to 130 meters . It is
therefore extremely important to monitor verticality in order to ensure continuity and connection between adjacent
diaphragm - wall panels .
The Enpafraise system monitors and records in real time three geometricals parameters :
- depth
- the angle of inclination of the hydrofraise frame in the plane of the diaphragm - wall (named right / left) .
- the angle of inclination in the perpendicular plane (named upstream / downstream).
The data is plotted directly on deflection vs depth curves . For example , the observed deflections during
construction of a deep diaphragm - wall at Navajo dam (USA) , shown below were less than 1/1000 , confirming
the efficiency of the Enpafraise sustem for monitoring and correcting deflections at great depths .
The Enpafraise also records three mechanical parameters :
- drilling speed
- torque of each of the two independant cutting wheel motors
These parameters are directly proportional to the hardness of the soil / rock layers encountered . Their record
provides a geotechnical profile such as in the example shown below of a deep cut - off installed from the crest of a
dam , where the core / base rock contact level appears very clearly .
Major projects on which the Enpafraise system has been uesd include :
1985 Fontenelle dam , USA
1986 Dunakiliti dam , Hungary
1986 88 Vienna subway , Austria
1987-88 Navajo dam , USA
1987-88 Sangatte access shaft (channel tunnel)
1988-90 Mud Moutain dam , USA
1989-90 Monaco , complex # 1
1991 National Library , Paris
Bourse car park , Lyons
CDG airport ,Paris
1993 Kuala Lumpur City Centre L'AGLY dam , France