Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Longitudinal settlements during tunneling in soft Clay, using transparent soil models
https://orcid.org/0000-0001-8245-1451
Highlights Transparent clay surrogate employed to visualize subsurface longitudinal settlement. Effect of C/D ratio and ground loss at tunnel face on deformation profile explored. Measured subsurface settlements were noticeably larger than surface ones. Volumetric strains demonstrate the formation of an arching zone. Role of overburden on and flattening of surface settlements identified.
Abstract The purpose of this study was to measure internal longitudinal displacements taking place during tunnel excavation and compare them to the displacements predicted using available analytical and empirical formulations. A physical model made with transparent soil permitted exploring the internal soil deformations, within the supporting soils. A soil surrogate made of Magnesium Lithium Phyllosilicate (MLPS) was used to represent soft clay. Tunneling was simulated using a moveable trap door arrangement for different face losses ranging from 5 to 30% D. Internal soil movements in the longitudinal direction were captured for three cover-to-diameter (C/D) ratios ranging from 1.5 to 3.5. Shear as well as volumetric strains were computed using the captured spatial displacements. The results demonstrate that the shape of the longitudinal profile is more dependent on the overburden depth of the tunnel in comparison to face losses, in particular: (i) subsurface settlement is approximately 2–4 times the observed surface settlement for the same C/D ratio; (ii) a longitudinal soil arch is likely to form with the increase of C/D ratio which limits the observed settlement; and (iii) shear strain fields showed that a cascading failure may occur with the increase in face movements, especially for shallow tunnels. Finally, the computed and measured surface and subsurface settlement profiles were generally in agreement especially as C/D increases, thus validating methods used to predict subsurface settlements where measurements are sparse.
Longitudinal settlements during tunneling in soft Clay, using transparent soil models
https://orcid.org/0000-0001-8245-1451
Highlights Transparent clay surrogate employed to visualize subsurface longitudinal settlement. Effect of C/D ratio and ground loss at tunnel face on deformation profile explored. Measured subsurface settlements were noticeably larger than surface ones. Volumetric strains demonstrate the formation of an arching zone. Role of overburden on and flattening of surface settlements identified.
Abstract The purpose of this study was to measure internal longitudinal displacements taking place during tunnel excavation and compare them to the displacements predicted using available analytical and empirical formulations. A physical model made with transparent soil permitted exploring the internal soil deformations, within the supporting soils. A soil surrogate made of Magnesium Lithium Phyllosilicate (MLPS) was used to represent soft clay. Tunneling was simulated using a moveable trap door arrangement for different face losses ranging from 5 to 30% D. Internal soil movements in the longitudinal direction were captured for three cover-to-diameter (C/D) ratios ranging from 1.5 to 3.5. Shear as well as volumetric strains were computed using the captured spatial displacements. The results demonstrate that the shape of the longitudinal profile is more dependent on the overburden depth of the tunnel in comparison to face losses, in particular: (i) subsurface settlement is approximately 2–4 times the observed surface settlement for the same C/D ratio; (ii) a longitudinal soil arch is likely to form with the increase of C/D ratio which limits the observed settlement; and (iii) shear strain fields showed that a cascading failure may occur with the increase in face movements, especially for shallow tunnels. Finally, the computed and measured surface and subsurface settlement profiles were generally in agreement especially as C/D increases, thus validating methods used to predict subsurface settlements where measurements are sparse.
Longitudinal settlements during tunneling in soft Clay, using transparent soil models
https://orcid.org/0000-0001-8245-1451
Highlights Transparent clay surrogate employed to visualize subsurface longitudinal settlement. Effect of C/D ratio and ground loss at tunnel face on deformation profile explored. Measured subsurface settlements were noticeably larger than surface ones. Volumetric strains demonstrate the formation of an arching zone. Role of overburden on and flattening of surface settlements identified.
Abstract The purpose of this study was to measure internal longitudinal displacements taking place during tunnel excavation and compare them to the displacements predicted using available analytical and empirical formulations. A physical model made with transparent soil permitted exploring the internal soil deformations, within the supporting soils. A soil surrogate made of Magnesium Lithium Phyllosilicate (MLPS) was used to represent soft clay. Tunneling was simulated using a moveable trap door arrangement for different face losses ranging from 5 to 30% D. Internal soil movements in the longitudinal direction were captured for three cover-to-diameter (C/D) ratios ranging from 1.5 to 3.5. Shear as well as volumetric strains were computed using the captured spatial displacements. The results demonstrate that the shape of the longitudinal profile is more dependent on the overburden depth of the tunnel in comparison to face losses, in particular: (i) subsurface settlement is approximately 2–4 times the observed surface settlement for the same C/D ratio; (ii) a longitudinal soil arch is likely to form with the increase of C/D ratio which limits the observed settlement; and (iii) shear strain fields showed that a cascading failure may occur with the increase in face movements, especially for shallow tunnels. Finally, the computed and measured surface and subsurface settlement profiles were generally in agreement especially as C/D increases, thus validating methods used to predict subsurface settlements where measurements are sparse.
Longitudinal settlements during tunneling in soft Clay, using transparent soil models
Ads, Abdelaziz (Autor:in) / Shariful Islam, Md (Autor:in) / Iskander, Magued (Autor:in)
06.02.2023
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Longitudinal surface settlements induced by EPB tunneling in Bangkok Clay
| British Library Conference Proceedings | 2007
Models for predicting surface settlements due to soft ground tunneling
| British Library Conference Proceedings | 2000
Settlements induced by tunneling in Soft Ground
British Library Online Contents | 2007
Settlements induced by tunneling in Soft Ground
Elsevier | 2006