METHOD FOR MEASURING DISCHARGE QUANTITY OF PILE MATERIAL IN PILE PLACING CONSTRUCTION

摘要

PURPOSE:To improve the accuracy of measurement of discharge quantity of the pile material by detecting the sound wave of an inline air column with two microphones provided inside of a casing and inside of a fitting cable connected to the casing, and obtaining a position of the top surface of the pile material on the basis of the detecting signal. CONSTITUTION:The sound wave is radiated from a speaker 34 to the inside of a casing 2 by a sound generating device provided outside of the casing 2. The resonance sound of this sound wave is detected by a first microphone 36 provided inside of the casing 2 and a second microphone 41 provided in a spherical and hollow fitting case 40 connected to the peripheral part of the casing 2, and the detected signal is output to a frequency analyzer 37. Resonance frequencies f0, f1 are analyzed by the frequency analyzer 37 to be transferred to an inline air column computing unit 38, and length l of the inline air column is obtained to compute a top surface position of the pile material 5. Discharge quantity of the pile material is thereby measured independently from the distribution of temperature.