Abstract: The invention relates to an earth pressure system shield process. First of all, an excavation additive consisting of the mixture of an agent for improving fluidity and viscosity of an excavated soil and a mud improving main agent is added (Ic, P.sub.2) to the excavated soil at the time of shield excavation at the working face, inside a mixing chamber (1b) of a shield machine (1) and inside a soil discharge screw conveyor (3) to sufficiently mix the excavated soil with the improving main agent and a mud improving assistant agent is then added (5) inside the soil discharge screw conveyor (3), so that the seal covered by the improving main agent so as not to be disssolved in water is removed chemically by this assistant agent. In this manner, the excavated soil is improved to a high quality soil having low fluidity inside the soil discharge screw conveyor (3) and is discharged.

Abstract: A drilling bucket apparatus for expanding a bore-hole bottom for a cast-in-place pile. Drill bits are pivotally suspended from the upper portion of a drill pipe, which is a main frame of the apparatus, and are expanded and retracted radially by means of hydraulic cylinders. A bucket is attached to the lower end of the drill pipe and scrapers are installed on the side of the bucket. The scrapers are arranged to open and close sideward, following the movement of the drill bits. During drilling work, the apparatus is suspended from a kelly bar of a drilling machine. When the apparatus is rotated and the drill bits are expanded, the whole expanded shape of a bore-hole bottom is drilled simultaneously and cuttings are scraped into the bucket by means of the drill bits and the scrapers. Further, a bottom lid of the bucket can be released by operating a hydraulically-actuated opening laver, whereby, cuttings are discharged automatically.