N-VALUE DETECTION METHOD, N-VALUE DETECTOR, AND PILE HOLE DRILLING UNIT

摘要

PROBLEM TO BE SOLVED: To solve the problem that a pile hole is obliquely formed because a presently mainstream pile hole drilling unit employing a hydraulic motor as a driving source cannot detect a precise N-value in real time during ground drilling operations, and because a direction of a drilling bucket is changed when the pile hole drilling unit collides with an undrillable obstacle such as a rock in the ground.

SOLUTION: The N-value of the ground midway through the drilling operation is detected from an input pressure value of the hydraulic motor as the driving source of the drilling bucket for drilling the ground, and a value of a rotational period of the hydraulic motor. Additionally, the N-value is monitored in real time during the drilling operation, so that the obstacle, a hard stratum, etc. in the ground can be detected to prevent the oblique formation of the pile hole.

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