LINING SHAPE MEASUREMENT OF TUNNEL CONSTRUCTED BY TIMBERING SUPPORT METHOD

矢板工法で建設されたトンネルの移動体レーザスキャニングによる覆工形状計測

Determining the cause of cracks in tunnel linings is important to establish an efficient repair scheme. This study addresses the use of the lining shape obtained using laser scanning for the investigation of the cause of cracks. A tunnel constructed by timbering support method was selected and considered to not be affected by any external force. Profiles of the tunnel lining were measured using a mobile laser scanner with improved accuracy. Curvature radii of the upper section of the tunnel lining were then determined by the proposed method using the three-dimensional point cloud obtained from the laser scanning results. The results showed the characteristic distribution of the curvature radii that were consistent throughout each installation interval of assembly form centering. It is difficult to consider that the distribution of the lining shape resulted from the deformation of the lining owing to an external force in the case when this type of distribution is observed. It is, therefore, concluded that the cracks in the lining were attributed to causes other than an external force, such as deformation of the concrete lining during the curing process. ひびわれが観察されたトンネル覆工の補修を合理的に行う上では,覆工のひびわれの原因を特定することが重要である.筆者らは,このための手掛かりとして,レーザスキャニングによる覆工の形状計測結果を用いることを試みた.矢板工法で建設され,外力の影響を受けていないと考えられるトンネルを対象とし,精度の向上を図った移動体型の計測システムを用いてレーザスキャニングを実施した.得られた3次元点群データより,独自の方法により覆工上半部の曲率半径を測定した.この結果,組立式型枠が設置された各スパンに共通する特徴的な曲率半径の分布を認めた.このような覆工形状の分布が見られる場合は,これが外力による覆工の変形によってもたらされるとは考えにくいことから,覆工に生じているひびわれが,覆工コンクリートの硬化過程の変形など外力以外に起因するものであると判断できる.

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  • English
  • Japanese

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  • Accession Number: 01633680
  • Record Type: Publication
  • Source Agency: Japan Science and Technology Agency (JST)
  • Files: TRIS, JSTAGE
  • Created Date: Feb 25 2017 3:24PM