| 摘要 |
PURPOSE:To smoothly perform the assembling work of segments in a tail plate by forming constriction sections so that the tail clearance of a shield machine having a duplicate circular cross section is made larger at the position of the constriction section of the tail plate than at the position of a circular arc section. CONSTITUTION:Circular arcs of multiple circles having different centers are connected via constriction sections as the cross sectional shape of a shield main body 1. A shield has a duplicate circle constituted of multiple circular arcs and at least one constriction section, and segments 4 are assembled into a duplicate circle along the inner face of the tail plate section of the shield main body 1 at the prescribed interval from the inner face. The tail clearance delta3 at the constriction section of the tail plate 2 is set larger than the tail clearance delta1 at the circular arc section. Even when the tail plate is deformed larger at the constriction section than at the circular arc section by the earth load from the natural ground and the tail clearance is reduced, the tail clearance necessary and sufficient for the assembling work of the segments 4 is secured at the constriction section. |
