Civil and Environmental Engineering - Journal articles
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Item The impact of thermal–hydraulic variation on tunnel long-term performance: a tale of two tunnels(ICE Publishing; ICE Publishing collections are provided by Emerald Publishing, 2024-09-28) Wang, Chao ; Xiao, Zhipeng ; Di Murro, Vanessa ; Osborne, John; Friedman, Miles ; Li, Zili ; Irish Research Council; Horizon 2020; H2020 Marie Skłodowska-Curie Actions; Science Foundation Ireland; Transport Infrastructure IrelandLong-term structural performance of ageing tunnels is influenced by various natural and anthropogenic factors. This study examines the impacts of two rarely investigated climatic factors: rainfall and temperature. Two dedicated case studies were conducted on the European Organisation for Nuclear Research (CERN) TT10 tunnel and Dublin port tunnel (DPT) using distributed fibre optic strain sensing (DFOS) and wireless sensor network (WSN) monitoring, respectively. DFOS data showed an increasing deformation in TT10 tunnel, attributed to tunnel deteriorations and ground deformation, with seasonal variation of lining strains linked to rainfall-related seasonal change in pore water pressure. However, inconsistencies in the rainfall–strain correlation were also noted due to geological complexities and varying pore water pressure sources. In contrast, WSN measurements showed that DPT deformation correlated with temperature, instead of precipitation. DPT deformation increased in warmer seasons and decreased in colder ones, in the absence of external disturbances, comprising reversible thermal deformation and irreversible deterioration-induced deformation. Over time, cyclic and periodic temperature changes caused elastic deformation to reverse, while plastic deformation accumulated, leading to ongoing tunnel deformation. These findings bring more insights into the resilience of critical underground infrastructure vulnerable to climate change, groundwater variations and other environmental factors.Item Modelling the impact of deterioration on the long-term performance of Dublin Tunnel(Canadian Science Publishing, 2024-09-11) Wang, Chao; Xiao, Zhipeng; Friedman, Miles; Li, Zili; Science Foundation Ireland; Transport Infrastructure Ireland; National Natural Science Foundation of ChinaThe influence of tunnel deteriorations on its long-term performance has received extensive attention recently. Most studies considered deteriorations by manually varying the magnitude of parameters like permeability and stiffness, neglecting their time-dependent variation. This paper addresses this gap by investigating the impact of time-dependent deteriorations on the long-term behaviour of the aging Dublin Port Tunnel (DPT). A modified analytical relative ground-lining permeability model and calculated deteriorated permeability for DPT were presented, with steps and procedures generalised. The deteriorated permeability was incorporated into the hydraulic deterioration model, together with mechanical deterioration, offering a more holistic and realistic prediction of DPT’s long-term performance than previously available. Numerical results, compared against field measurements, showed (1) assuming constant permeability fails to accurately capture time-dependent liner deformation, and hydraulic deterioration is the dominant factor inducing an approaching squatting deformation mode; (2) continuous mechanical deterioration leads to a linear growth in vertical and horizontal convergence over time, with vertical convergence being more pronounced, indicating a squatting contraction deformation mode; (3) the comparison quantitatively evaluates the impact of individual and coupled hydro-mechanical deterioration on DPT’s long-term behaviour and the agreement between field data and numerical results confirms coupled lining deterioration is the root cause behind the observation.Item Investigation of aero-hydro-elastic-mooring behavior of a H-type floating vertical axis wind turbine using coupled CFD-FEM method(Elsevier Ltd., 2024-07-02) Liu, Qingsong; Bashir, Musa; Iglesias, Gregorio; Miao, Weipao; Yue, Minnan; Xu, Zifei; Yang, Yang; Li, Chun; National Natural Science Foundation of ChinaFloating vertical axis wind turbines (VAWTs) are being explored as a promising new option for harnessing offshore wind energy due to their unique advantages, including low installation and maintenance costs, high operational efficiency in wind farm clusters, and scalability of rotor sizes. However, the lack of software capable of simulating the aeroelastic of VAWTs poses a significant barrier to their further development and deployment. The aim of this paper is to develop a fully coupled aero-hydro-elastic-mooring-material model for floating VAWTs. The aerodynamic performance, hydrodynamic response and structural nonlinearities of the floating VAWT are analyzed in detail using Computational Fluid Dynamics (CFD) and the Finite Element Method (FEM). The results indicate that: (i) The dynamic response of the floating VAWT platform results in more pronounced fluctuations in the power coefficient, characterized by frequent spike-like extreme values, compared to fixed VAWT. Nevertheless, wake dissipation in floating VAWT is quicker, facilitating faster flow recovery and a more marked acceleration effect in the flow field. (ii) The surge and pitch motions of the platform affect the velocity of the blades relative to the fluid, resulting in additive and subtractive effects with the incoming flow. This interaction gives the blade torque of the floating VAWT an alternating performance advantage in the upwind region, compared to fixed VAWT; (iii) Stress analysis reveals that the highest levels of stress occur at the juncture between the support arm and the blade, with significant stress also present at the bottom of the central pontoon. In contrast, the blade tips exhibit the lowest stress levels. (iv) The blades of the floating VAWT undergo radial deformation due to wind loads and centrifugal forces, while the support arms experience vertical vibrations, driven by their own weight combined with that of the blades. (v) The mooring lines, particularly influenced by platform traction and frequent interactions with the seabed, show dynamic shifts in maximum contact pressures, especially between moorings C2 and C3. Mooring C2, located on the windward side, consistently faces more intense seabed interactions.Item Investigation of barge-type FOWT in the context of concurrent and cascading failures within the mooring systems(Elsevier Ltd., 2024-02-19) Jia, Wenzhe; Liu, Qingsong; Iglesias, Gregorio; Miao, Weipao; Yue, Minnan; Yang, Yang; Li, Chun; National Natural Science Foundation of China; Shanghai Non-carbon Energy Conversion and Utilization InstituteThe design requirements for offshore engineering stipulate that floating structures should maintain their overall performance even in the event of a single mooring line failure. However, it is crucial to ensure that the platform does not drift or capsize in the case of two mooring line failures. Therefore, the investigation into the dynamic response of wind turbines after mooring line failures is of great significance. In this study, the aerodynamic-structural simulation capability of FAST was coupled with the hydrodynamic analysis software AQWA by modifying the dynamic link library. The dynamic response of a Barge-type floating offshore wind turbine (FOWT) and the variations in mooring line tensions were computed under different sea conditions after the successive failures of two mooring lines with varying time intervals. The findings reveal that in rated sea conditions, there is a significant increase in surge motion, reaching a maximum value 2.08 times that of the original, following the failure of two mooring lines. The tension in mooring line #3 reaches 1.57 times the pre-failure value. In extreme sea conditions, the simultaneous failure of two mooring lines at the same corner triggers a cascading failure phenomenon within the mooring system, and a shorter interval between failures amplifies the dynamic response of the platform. Therefore, it is not advisable to deploy the Barge platform in harsh environmental conditions.Item Stability analysis of tunnel face considering the shape of excavation and reinforcement measures(Taylor & Francis, 2024-08-14) Jiang, Yin; Tong, Yueping; Ouyang, Aohui; Ye, Fei; Liu, Chang; Han, Xingbo; Peng, Wenbo; National Natural Science Foundation of ChinaIn mountain tunnels, a series of advanced reinforcement measures are often employed to maintain the stability of the tunnel face, particularly in challenging geological conditions. However, there is a lack of design theories regarding the advanced support structure for uniquely shaped tunnel faces, necessitating further exploration. Based on the limit equilibrium method, this paper presents a derivation of the mechanical model for analyzing excavation face stability considering shape changes and bolts. Additionally, a design theory for horizontal glass fiber bolts in longitudinally inclined tunnel faces is established. The reinforcement effect of the pipe shed is further considered. Finally, the proposed model is validated, and parameter analysis is conducted to guide design practices.