| 摘要 |
PURPOSE: To easily make use of a reactive force on thrusting an excavating machine, by providing a bag-form sealing material made of a cylindrical elastic material at the external periphery of steel supports of a soft ground tunnel and expanding it with air to closely stick it to the ground. CONSTITUTION: An expansive sealing material 1 made of an elastic material provided with an air supply pipe is detachably fitted to the outer periphery of circular supports 18. The sealing material 1 is filled with air to expand and stick to the ground A with pressure and then the supports 18 are fixed. When an excavating machine is thrusted, it is transferred by making use of the reaction obtained by a reaction force receiver 17 fixed to the support 18. After advance of the excavating machine, new supports 18 are erected at the space and the elastic sealing material is transferred. Thereafter, this process is consecutively repeated to excavate the tunnel. In this way, a tunnel can be excavated even in a soft ground without use of costly segments. |
