| 摘要 |
PURPOSE:To form a high-precise ditch hole, by a method wherein shoes at a guide part of a ditch hole excavator are secured to two guide columns secured to a ground, a ditch hole is excavated by a turning cutter, the shoes are released to lower the excavator by a full stroke, and an excavation is conducted in the same manner described above. CONSTITUTION:In the construction of a veery deep underground continuous wall, a cylindrical hole 26, being perpendicular to a ground 25, is bored, a steel guide column body 27, having guide parts at both sides, is then erected in a reference hole 26, concrete 28 is placed in a hollow part to construct a guide column 4, and a space between the guide column 4 and the reference hole 26 is filled with gravel 29. Shoes 6 and 7 at both sides of an expandable support frame 3 are then placed on a guide part 5 of the guide column 4 secured in the ground. Through expansion of a securing expander 2, the shoes 6, 7 are secured to the guide columns 4, and a part around a support shaft 10 is rocked with a cutter 8 turned by means of a drive gear 18 to excavate a ditch hole 30. Through repetition of said procedures, the ditch hole 30 is trenched down to a a given depth. |
