METHOD OF AND APPARATUS FOR PROVIDING AN UNDERGROUND TUNNEL

摘要

A method of an apparatus for providing a continuous underground tunnel utilizes an elongate boring device (14) including a forward facing off-axis high pressure fluid jet (36) which is roated about the axis (63) of the device (14) while the latter is urged forward through the soil, thereby to cause the device (14) to bore a tunnel through the soil as it moves forward. The boring device (14) is steered by modulating the speed and/or the direction of rotation of the off-axis fluid jet (36) in a way which depends upon the desired direction to be taken by the boring device (14) within the soil The pitch angle of the boring device (14), as defined by its axis (63), is monitored relative to a horizontal ground plane, independent of the roll position of the device (14). The roll angle of the boring device (14) and the position of its off-axis jet (36) are simultaneously monitored thereby to monitor the precise rotational position of the jet (36) relative to its roll position.