Complemental concrete lining is ofen required to maintain sufficient durability of a shield tunnel in high underground water pressure. However, in case of a long tunnel, it is quite difficult to achieve water-proof ability and pumpability of concrete simultaneously, because W/C ratio, which greatly affects pumpability, should be restrained small. To retain these two controversial functions, we executed several lining tests, changing the combination of concrete ingredients, and examining the workability as well as the looking of lining surface. As a result, we succeeded to select the best combination and completed the following regular lining without any visible defects.
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