To provide an automatic penetration tester capable of detecting an accurate self-sinking load.
Only a load is applied to a penetration rod, and the penetration rod is self-sunk and penetrated into the ground while increasing-decreasing the load. When the penetration rod is not self-sunk and peretrated even by a predetermined load, the penetration rod is rotated and rotatably penetrated while applying the load. When reducing the load in self-sinking and penetration or when stopping rotation of the penetration rod in rotational penetration, inertia is removed by forcibly restraining penetration of the penetration rod (S001), and the load applied to the penetration rod is reduced up to a load without self-sinking (S002). Processing is performed for gradually increasing the load until the penetration rod starts to self-sink from there (S004 and S005). Thus, the accurate self-sinking load can be provided.
TAKEDA KAZUHIRO
SHIOMI MITSUNORI
