不陸な地盤面上での3Dプリンティング技術の開発と検証
現地地盤の不陸に合わせてオンサイトで直接3Dプリントする技術が確立できれば，均しコンクリートや従来型施工の型枠組立・撤去が不要となり，工期短縮や適用工種の拡大が期待できる．本研究ではまず，T-3DP®用に不陸な地盤面の凹凸を避けながらプリントする機能を開発した．次に，比較的単純な斜面地盤および曲面地盤上で小規模な積層実験を行い，画像解析によりこれらの地盤上での積層安定性を確認した．最後に，土木工事で直面しうる急勾配かつ凹凸のある地盤を想定し，最大勾配80%かつ最大高低差約100 mmの凹凸を設けた模擬地盤上にコンクリート部材の埋設型枠をプリントする実験を行った．3Dスキャナーでの測定により，良好な出来形を確認した．また，構築した3DP型枠に，プリント構築から18時間後にコンクリートを打込み，埋設型枠として使用可能なことを確認した．
キーワード：T-3DP®，3Dプリント，不陸面，3Dスキャン，積層安定性，埋設型枠
＊１ 技術センター社会基盤技術研究部 材工研究室
＊２ 技術センター社会基盤技術研究部先端基盤研究室
＊３ 技術センター生産技術開発部地下空間技術開発室
＊４ 土木本部土木技術部
Development and Validation of Direct 3D Printing Technology on Uneven Grounds
On-site direct 3D printing (3DP) on uneven ground will allow shortening of construction period and wider application of 3DP, since it eliminates the need for the construction of leveling concrete and the assembly and removal of formwork that would be required in conventional construction. First, the authors developed a method for T-3DP that can print while avoiding the unevenness of the ground surface. Next, small-scale printing experiments were conducted on comparatively simple sloping ground and curved ground, and the buildability was confirmed to be stable by image analysis. Finally, a large-scale printing experiment was conducted in which a permanent formwork of a concrete member was printed on artificial ground with a maximum slope of 80% and a maximum height difference of approximately 100 mm, envisaging the steep and uneven ground surfaces that can be seen in practical construction projects. Good shape accuracy was confirmed by measurement with a 3D scanner. Concrete was cast into the 3D-printed formwork 18 hours after print construction, which demonstrated that the printed formwork was sufficiently strong at that point.
Keywords: T-3DP, 3D printing, uneven ground, 3D scanning, buildability, permanent formwork
*1 Structure and Material Research Section, Infrastructure Technology Research Department, Taisei Advanced Center of Technology
*2 Advanced Infrastructure Technology Research Section, Infrastructure Technology Research Department, Taisei Advanced Center of Technology
*3 Underground Utilization Technology Development Section, Production Engineering Technology Department, Taisei Advanced Center of Technology
*4 Construction Engineering Department, Civil Engineering Division