| 摘要 |
PROBLEM TO BE SOLVED: To cope with a squeezing ground, etc., easily by changing over and jointly using gripper propulsion and shield jack propulsion, and to prevent pene tration into a tunnel boring machine of soil and sand by installing a split type front support covering approximately the whole circumference of the outer circumference of the front section of a boring machine body while being able to be contacted or separated with or from a pit wall. SOLUTION: A cutter head 3 is borne rotatably to the front section of a main beam 1 through a cutter head support, and a gripper device 5 is mounted on a rear section longitudinally slidably through a thrust jack 4 to the cutter head support. A split type front support 9 covering approximately the whole circumference of the outer circumference of the front section of a boring machine body while being able to be contacted or separated with or from a pit wall is set up to the cutter head support. Accordingly, since gripper propulsion and shield jack propulsion can be changed over or used jointly in response to the conditions of a squeezing ground while the front support 9 is pushed against the ground and excavation can be conducted at the time of excavation, the ground can be held without loosening up to the place of the assembling of a timbering. |
