| 摘要 |
PURPOSE:To excavate tunnels having two kinds of diameters with different sections in succession without changing a device, etc., to reduce a construction period to get away with a simple auxiliary method such as a chemical grouting method, etc., and to promote economic efficiency and work efficiency. CONSTITUTION:In such a state that a small sectional shield excavator 2 is housed into a large sectional shield excavator 3 to connect both of them with each other, cutters 2b and 3a of both of them are connected with each other to form a large sectional tunnel Ta. A small sectional tunnel Tb is excavated in succession from the large sectional tunnel Ta by branching off and driving forward the small sectional shield excavator 2 separately. |
