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In the study, the authors carried out laboratory experiments and numerical analysis to verify how the curing environment and construction method of lining concrete cause cracks, so that they may prevent concrete pieces from falling and improve the long-term health of lining concrete. As a result, they found that the necessary compactness of concrete surface can be secured, if the concrete is cured in a wet condition for 7 days. As for the construction method, applying excessive compaction energy did not have a major impact on the quality of concrete. The authors also analyzed the crack propagation based on the physical properties obtained from laboratory tests. It was found that harmful cracks were not generated in the short-term (50 days), and in the long-term (50 years), occurrence and crack propagation caused by shrinkage strain of the concrete were not influenced by the curing environment. Based on these findings, the authors will propose construction management guidelines for medium-fluidity lining concrete. 本研究では，コンクリート片のはく落防止によるトンネル覆工の長期健全性向上を目的に，ひびわれ発生の原因となる養生環境や施工方法について室内実験と数値解析で検証を行った．検証の結果，養生環境については，７日間湿潤状態に保つ養生を行えばコンクリート表面の緻密性等の品質を確保できる．施工方法については，締固めエネルギーが過剰となってもコンクリートの品質には大きな影響がなかった．室内試験結果から得られた物性値をもとに，ひびわれ進展解析を行ったところ，短期的（50日）には有害なひびわれは発生しなかった．また，長期的（50年）には，コンクリートの収縮ひずみに起因するひびわれの発生，進展は養生環境に関係しないことがわかった．これらの結果から，中流動覆工コンクリートの施工管理基準の提案を行う． |
