| 摘要 |
PURPOSE:To enable the use of a small jack using hyraulic presure with a smaller compression level of the subsoil at the directional correction by retracting the propulsion advanced side end of an underground structure 1 with a jack while the propulsion lagged side thereof is thrusted with a jack. CONSTITUTION:A steel pressurizing frame 4 is placed on the top of an under- ground structure such as caisson and fixed 5. Around the underground structure 1, the upper end of an anchor rod 3 with the lower end thereof inserted into an anchor hole in the subsoil 2 is connected to the lower end of a piston rod 14 of a hydraulic jack 10 through a coupling 13. To advance said undeground atructure 1, each hydraulic jack is retracted. Here, when the directional correction of the underground structure 1 is made, split support base 17A-17D are placed at the bottom of the advanced side hydraulic jack 10A, the coupling 13 is fitted into a retaining section 18 at the top of the support base 17, and both ends of a retaining pin 15 is fitted into a receiving groove 19. In such a condition, the jacks 10a and 10b are stretched or retracted separately to effect a directional correction. |
