Rotary hole bit pressure variable type ground strength measuring method

摘要

PURPOSE:To simultaneously calculate the coefficients related to a shearing resistance angle and tackiness by providing a mechanism changing the bit pressure acting on the drilling surface of a bit in predetermined magnitude at a predetermined cycle and a mechanism measuring the rotary torque and bit pressure of the bit. CONSTITUTION:A motor 4 for rotating a boring rod 2, a load cell 5 for measuring torque and bit pressure and an electric type depth gauge 6 for measuring drilling depth are mounted on the moving body 3 sliding along a guide support 1. In vibration pressure type drilling measurement, a pump 11 is operated by a power source 9 and the rotational speed of the rod is set by a flow rate control valve 12. Next, the average pressing force of a bit is measured on the basis of the fluid difference pressure due to the up-and-down movement of the piston of a cylinder 12 by flow rate control valves 13, 14, 15 and the cyclic variation and amplitude of bit pressure are measured by a solenoid valve 16 and recording, calculation and display are performed by the computer received in a measurement control and recording box 8.