The name refers to a cast in place wall, excavated with conventional equipment under bentonite slurry. Subsequent concreting is done with a deformable, watertight, plastic concrete, composed of 100-200 kg/m³ cement, 1,800-2,000 kg/m³ well graded aggregate and 30-40 kg/m³ bentonite. Typical wall thickness is 0.6 m. Installation is done by alternate panels and stop-end tubes are used.

This method allows to install very deep walls (50 m or more), but for very large depths, wall thickness should be increased to 1 or 1.2 m in order to reduce the risk of gaps near panel joints which may be caused by deviations.