| 摘要 |
<p>PURPOSE:To prevent the breakage of a confluence tube due to vibration of excavation work by a method in which a confluence inner tube is inserted into a confluence outer tube having connecting screw on its both ends and held by a buffer material to form a confluence tube for injecting chemical grout. CONSTITUTION:A confluence inner tube 28 is inserted into a confluence outer tube 23 having connecting screws 23a and 23b for a composite tube and a bit and held by a rubber valve seat 24 having a liquid-passing hole 24b and an annular valve 26 to form a confluence tube 11 for injecting chemical grout. The tube 11 is connected to the lower part of a composite tube with the screw 23a. While the ground is excavated by a bit connected with the screw 23b, the tube 11 is penetrated to a given depth into soft ground. While the composite tube is pulled out, chemial grout is sent through the outer and inner liquid passages, mixed in the tube 11, and injected into the ground. Since the inner tube 28 is held by the valve seat 24 having buffer action, the breakage of the inner tube 28 due to the vibration to be occurred in excavation can be prevented.</p> |
