TY - THES

T1 - 3D Finite Element Analysis of building lot “Wolframstraße”

AU - Granitzer, Andreas-Nizar

N1 - embargoed until 07-11-2022

PY - 2019

Y1 - 2019

N2 - The objective of this thesis is to analyse the structural response of the existing drainage tunnel HWS to the excavation of the suburban railway project “Wolframstraße” conducted above the tunnel axis. Of main concern are the determination of anisotropic lining parameters as well as the structural performance during different construction phases using the FE software PLAXIS. Due to the presence of construction joints, shield-driven tunnel linings, such as the HWS, are expected to behave anisotropic rather than isotropic. A parameter derivation process, which poses the core of the preliminary study, is therefore established in order to model the structural behaviour of the tunnel lining as realistically as possible. To this end, the lining is considered as direct-joint model as well as indirect-joint model. For the latter, the basic idea of adapting the stiffness components of the lining as a consequence of segmental joints is discussed in detail. In addition, a distinction is made between loading and unloading conditions to account for the actual spatial boundary conditions of the HWS. The results showed that the cross-sectional behaviour of the concerned lining configuration is not affected by the rotational stiffness of the longitudinal joints at all. In contrast, ring joints were expected to affect the longitudinal deformation behaviour significantly. Similarly, the structural forces of the lining were particularly influenced by the ring joint-induced shear stiffness reduction. However, different tendencies were observed for loading and unloading conditions. As a consequence of both, the complex geometrical conditions and the construction program of the considered project, full 3D modelling was required. The results of the performed sensitivity study underlined the importance of the considered model dimensions on the calculation output. To this end, the model depth was validated based on the distribution of the Small Strain Stiffness ratio. The results showed that the heave of the tunnel crown decreases as the distance between the excavation axis and the tunnel increases. Moreover, the structural behaviour of the lining appeared to be less affected as the above excavation proceeds. It was further inferred from the results that the structural forces significantly vary between the construction phases which might be critical to the lining design. The general response of the lining due to heavy rainfall effects was longitudinal settlement.

AB - The objective of this thesis is to analyse the structural response of the existing drainage tunnel HWS to the excavation of the suburban railway project “Wolframstraße” conducted above the tunnel axis. Of main concern are the determination of anisotropic lining parameters as well as the structural performance during different construction phases using the FE software PLAXIS. Due to the presence of construction joints, shield-driven tunnel linings, such as the HWS, are expected to behave anisotropic rather than isotropic. A parameter derivation process, which poses the core of the preliminary study, is therefore established in order to model the structural behaviour of the tunnel lining as realistically as possible. To this end, the lining is considered as direct-joint model as well as indirect-joint model. For the latter, the basic idea of adapting the stiffness components of the lining as a consequence of segmental joints is discussed in detail. In addition, a distinction is made between loading and unloading conditions to account for the actual spatial boundary conditions of the HWS. The results showed that the cross-sectional behaviour of the concerned lining configuration is not affected by the rotational stiffness of the longitudinal joints at all. In contrast, ring joints were expected to affect the longitudinal deformation behaviour significantly. Similarly, the structural forces of the lining were particularly influenced by the ring joint-induced shear stiffness reduction. However, different tendencies were observed for loading and unloading conditions. As a consequence of both, the complex geometrical conditions and the construction program of the considered project, full 3D modelling was required. The results of the performed sensitivity study underlined the importance of the considered model dimensions on the calculation output. To this end, the model depth was validated based on the distribution of the Small Strain Stiffness ratio. The results showed that the heave of the tunnel crown decreases as the distance between the excavation axis and the tunnel increases. Moreover, the structural behaviour of the lining appeared to be less affected as the above excavation proceeds. It was further inferred from the results that the structural forces significantly vary between the construction phases which might be critical to the lining design. The general response of the lining due to heavy rainfall effects was longitudinal settlement.

KW - Finite-Elemente-Methode

KW - Tunnel

KW - Anisotropie

KW - Finite-element method

KW - Tunnel

KW - Anisotropy

M3 - Master's Thesis

ER -