| 摘要 |
PURPOSE:To cope with such as extrusion or sudden spring out of muddy water sufficiently, and to prevent such as delay in term of work owing thereto by investigating natural ground with use of a static cone when a tunnel is excavated. CONSTITUTION:A cone penetrometer 8 of a static cone 3 is pushed out before an excavating device 2 from inside of a partition wall 5 on a shield excavator 1, soil of a body to be excavated (such as hill-side) is investigated and cohesion, internal friction force and the like are known beforehand. The shield excavator 1 is then closed at a penetrated hole 11 on the partition wall 5 with a gate valve 12 before the cone penetrometer 8 is pushed out, and when the cone penetrometer 8 is pushed out, the gate valve 12 is opened, the penetrated hole 11 is opened and it becomes possible to pass through the cone penetrometer 8 and a rod 7. It is thus possible to foreknow soil conditions such as cohesion, internal friction force, weight per unit volume, groundwater level and pore water pressure before excavation. |
