| 摘要 |
PURPOSE:To effectively and safely perform pit excavation work on a large scale by a method in which water is stored in a caisson to make the whole of the caisson a self-supporting type sheathing wall, and the portion surrounded by the caisson is open-cut. CONSTITUTION:The ground at the cutting blade 7 position of a caisson 1 is excavated to form the space surrounded by the cutting blade 7, an underground beam 8,and side walls 2. Water is then stored in the caisson 1, the ground below the caisson 1 is excavated, the excavated soil and sand are discharged by a drain pipe 10, water is jetted from a jet pipe 11, and the caisson 1 with a structural base 9 are settled together by utilizing reaction in the earth anchor 12. The base 9 is pulled up, the side wall 2 of the caisson 1 is added, the caisson 1 is settled to a given depth, a bottom cover 3 is provided, and a grout is injected into the cutting blade 7 portion. The caisson 1 is likewise continuously connected with the outside circumference of the excavated portion 5, and under the condition that the level of water in the caisson 1 is maintained, the excavated portion 5 is open-cut. |
