POSITION DETECTION OF FRONT END OF EXCAVATION IN UNDERGROUND EXCAVATION PROCESS

摘要

PURPOSE:To accurately detect the horizontal position of excavation front end, by inserting a transmitter at the front end through the inside of internal pipe of a double pipe type excavator composed of an external pipe and an internal pipe and by receiving signals from the transmitter, on the ground. CONSTITUTION:A front bit 6 of a double pipe type excavator composed of an external and an internal pipe 1, 2 is rotated for excavation until it reaches a detecting position at the excavation front. Next, a sonde 3 having a transmitter therein is inserted from the pipe-free side to a container 4 at the front of the internal pipe 2. And the signals from the transmitter of sonde 3 are received by a receiver 5 placed on the ground to detect the position of excavation front according to the strength of signals or the like. The sonde 3 is recovered by a wire 6 after detection of position and corrected to a necessary direction. In this way, the horizontal position of excavation front can be accurately detected regardless of the depth and the underground water level and corrected the direction.