Force Reduction in Excavation Devices

Three new concepts are described for earth excavation, slurry-wall excavation, and rock boring. In each case the need for application of force from an external device is substantially reduced or eliminated. The slurry-wall excavator is a continuous excavation device suitable for foundation work or for placing thin, impermeable membranes in earthen dams. Wall stabilization can be via conventional slurry or by simultaneously cast-in-place concrete. The rock borer is a self-powered roller cutter device that requires neither thrust nor torque, and does not utilize wall jacks, drill steel, or a surface rotary drill rig. It can penetrate any material conventionally bored by tri-cone roller bits and, if suitably powered, can do so at substantially increased penetration rate. The earth excavator is under experimental development while the rock borer has been proven and is in initial stages of commercial production.