The design of the Hydrofraise excavation system makes it possible to drill barrettes or diaphragm-wall elements in a very wide range of soils, from cohesionless soils (silt, sand, gravel and cobbles up to 10 cm) to hard rock (50 to 100 MPa crushing strength).
A major advantage of the hydrofraise is that it eliminates the need for chiseling. This combined with the absence of vibration and shock makes the system very suitable for use on uran sites .
Overbreak is less than with conventional systems (less than 10 %) and correctable to under 0.2 %, if required).
Standard Hydrofraise equipment allows for several common wal widths for normal depths of less than 60 m.
Special models have been developed to attain depths of up to 150 m (Obayashi, Japan ; Mud Mountain dam , USA ; Navajo dam, USA) In 1992 a new type of low headroom and reduced weight Hydrofraise , HL 4000, was put into operation; this machine, with a telescopic guide frame and a height in operation of only 5 meters, can get into very tight spots such as frequently met on urban jobsites.
