To provide a screw point with which the same result as a conventional Sweden type sounding test can be obtained even by a novel testing method in which a load is reduced to 1/2 without generating variance in measured value.
A screw point 20 fitted atop of a rod includes a screw body part 21 which has a plurality of ridge parts, forming a spiral along a direction from a base end side toward a tip side, formed at an outer peripheral part thereof, a conic tip part 22 formed integrally with the tip side of the screw body part 21, a shaft part 23 formed integrally with the base end side of the screw body part 21, and a screw part 24 formed integrally with a base end side of the shaft 23 and fitted atop of the rod. In a sectional shape of the screw body part 21, a recessed part 21c formed on a front side of a ridge part 21a with respect to the rotating direction of the screw point is formed so that the radius of curvature gradually decreases from the base end side toward the tip side.
Hiroki Ogura
Takuya Fuji
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