| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an underground structure wherein an invert can be constructed by pumping heavyweight concrete in a shield tunnel, by solving the problem wherein conventional heavyweight concrete cannot be pumped due to poor flow property and thus needs to be precast for producing individual segments, which required complicated processes for construction, particularly adjustment processes such as positioning, alignment, etc. of individual precast members at installation. <P>SOLUTION: The underground structure comprises a heavyweight aggregate essentially comprising at least one chosen from FeO, Fe2O3 and metallic iron, provided that spherical particles account for 20% or more of total particles in the aggregate and particles that pass through a sieve with a nominal mesh size of 0.15 mm account for 10-20 mass% of the total particles in the aggregate. Alternatively, the underground structure comprises a heavyweight aggregate obtained by mixing a material recycled from a steelmaking process, provided that particles that pass through a sieve with a nominal mesh size of 1.2 mm account for 70-90 mass% of the total particles in the aggregate. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
