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The use of the “Pipe Arch” technique for under-crossing in urban areas
Published in Daniele Peila, Giulia Viggiani, Tarcisio Celestino, Tunnels and Underground Cities: Engineering and Innovation meet Archaeology, Architecture and Art, 2020
As anticipated, the structures just outside the natural stretch consist of two r.c. wells, one on the Venice side and one on the Tessera side. Both wells are made by a crown of piles arranged in plan according to an ellipse with major and minor axis respectively equal to 28.2 m and 24.0 m oriented with the minor axis aligned with the longitudinal development of the underpass. The vertical facing is achieved by using CFA piles Φ 800 mm; in some particularly sensitive areas from the point of view of possible failures and the effects of consolidation, a further row of CFA piles has been planned to further protect existing ones. Starting from the ground level, all the volume of soil behind the piles, has undergone a sub-vertical fluid-fluid jet grouting treatment in order to improve the mechanical characteristics of the pushing soil and guarantee the hydraulic seal. Similar treatment with jet grouting Φ 1500mm mesh 1200 x 1200mm has been performed to ensure the stability of the excavation bottom with a 5m thick bottom layer between -26m and -21m from ground level. The wells are excavated for samples of 1.5 m and, at each advance, a covering wall is laid down for under-construction by reinforced concrete rings anchored to the existing piles. The downward operations of the excavation plan inside the wells have been accompanied by the progressive execution of the interventions at the front (micropiles, insertions and injections with mortars) for the consolidation of the volume of land within which the natural tunnel is located.
The use of the “Pipe Arch” technique for under-crossing in urban areas
Published in Daniele Peila, Giulia Viggiani, Tarcisio Celestino, Tunnels and Underground Cities: Engineering and Innovation meet Archaeology, Architecture and Art, 2019
As anticipated, the structures just outside the natural stretch consist of two r.c. wells, one on the Venice side and one on the Tessera side. Both wells are made by a crown of piles arranged in plan according to an ellipse with major and minor axis respectively equal to 28.2 m and 24.0 m oriented with the minor axis aligned with the longitudinal development of the underpass. The vertical facing is achieved by using CFA piles Φ 800 mm; in some particularly sensitive areas from the point of view of possible failures and the effects of consolidation, a further row of CFA piles has been planned to further protect existing ones. Starting from the ground level, all the volume of soil behind the piles, has undergone a sub-vertical fluid-fluid jet grouting treatment in order to improve the mechanical characteristics of the pushing soil and guarantee the hydraulic seal. Similar treatment with jet grouting Φ 1500mm mesh 1200 x 1200mm has been performed to ensure the stability of the excavation bottom with a 5m thick bottom layer between -26m and -21m from ground level. The wells are excavated for samples of 1.5 m and, at each advance, a covering wall is laid down for under-construction by reinforced concrete rings anchored to the existing piles. The downward operations of the excavation plan inside the wells have been accompanied by the progressive execution of the interventions at the front (micropiles, insertions and injections with mortars) for the consolidation of the volume of land within which the natural tunnel is located.
Reduction in soil penetration resistance for suction-assisted installation of bucket foundation in sand
Published in Andrew McNamara, Sam Divall, Richard Goodey, Neil Taylor, Sarah Stallebrass, Jignasha Panchal, Physical Modelling in Geotechnics, 2018
The suction installation includes two stages as mentioned before. The self-weight installation is induced by the hydraulic piston working as a force controlled. The force of a magnitude equal to the self-weight of the model is applied. When the hydraulic seal is realized, the suction pressure is applied by a vacuum system through the valves attached to the bucket lid. The measurements of the penetration depth, the applied suction, u, and the pore pressure around the soil skirt are monitored during the installation.
Effect of the Grooved Rod on the Friction Force of U-Cup Hydraulic Rod Seal with Rough Lip
Published in Tribology Transactions, 2018
According to previous works, no paper has clearly defined those characteristics as the thesis exhibited by Crudu (10). In order to measure the roughness, an optical measuring device for surface topography (TALYSURF CCI 6000) was used (10−8 m accuracy). The experimental device was designed and built in the laboratory INOE 2000 IHP of Bucharest in Romania. This bench reproduces real operating conditions of a hydraulic seal and measures the friction force at constant pressure and speed.