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Journal articleMaddah Sadatieh MS, Tsiampousi A, Paschalis A, 2026,
Impact of Temporal and Spatial Resolution in Slope-Plant-Atmosphere Interaction Modelling.
, Geotech Geol Eng (Dordr), Vol: 44Soil-Plant-Atmosphere Interaction (SPAI) is an essential factor in slope behaviour, affecting water inflow and outflow, and thereby influencing Pore Water Pressures (PWP), soil strength and stiffness, and slope stability and serviceability. Due to its complexity, SPAI and its effect on slope behaviour are best described by hydro-mechanically coupled numerical analysis, rendering the boundary conditions (BC) used to replicate atmospheric conditions critical. Here, different considerations have been made regarding the temporal and spatial variation of these BCs to assess their effect on slope behaviour. Specifically, daily and monthly atmospheric data were contrasted, dynamic vegetation growth was juxtaposed with static vegetation, and water extraction with depth due to transpiration was compared with a simplified approach where evapotranspiration was modelled to occur from the ground surface. A representative cut slope was considered, and fully coupled hydro-mechanical analyses were conducted under different BCs to study its stability and serviceability. The numerical results highlight which modelling choices significantly influence predicted performance, particularly under climate change, and which can be safely simplified. Guidance is provided for balancing computational efficiency with accuracy in geotechnical design.
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Journal articleTantivangphaisal P, Taborda D, Kontoe S, et al., 2025,
Numerical modelling of the long-term cyclic response of laterally loaded piles driven in sands using the high-cycle accumulation framework
, Geotechnique: international journal of soil mechanics, Vol: 75, Pages: 1507-1523, ISSN: 0016-8505The High-Cycle Accumulation framework is modified and coupled with a practice-oriented cyclic sand constitutive model and implemented in a geotechnical finite elementsoftware to test the approach’s ability to predict the outcomes of monotonic and cyclic lateral loading field tests performed in Dunkirk, France, under the Pile-Soil Analysis (PISA) Joint Industry Project. A consistent and rational calibration procedure using only site-specific in-situ investigation and laboratory tests is presented and a single set of calibrated parameters is shown to reproduce Dunkirk sand’s response in monotonic, drained cyclic and undrained cyclic triaxial element tests up to 10,000 cycles, covering awide range of densities and stress conditions. The finite element analyses are shown to match well the monotonic lateral loading responses of fully instrumented 2m and 0.76m diameter open steel driven test piles and the latter’s cyclic lateral response up to 30,000 cycles. New insights into the evolution of the ground state under long-term lateral cyclic loading are gained to inform future research into practical site-specific methods for cyclic loading design over the full lifespan of piled foundations.
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Journal articleStewart M, Ruiz Lopez A, Tsiampousi A, 2025,
Three-dimensional interaction of twin tunnels numerical analysis of the Waterloo International Terminal case study
, Journal of Geotechnical and Geoenvironmental Engineering, Vol: 151, ISSN: 0733-9410Being able to predict with precision and certainty how existing tunnels respond to new tunnelling works in urban areas is vital for the safety of the existing tunnels and for minimising the cost and environmental impact of the new tunnels. The three-dimensional interaction of tunnels in stiff, overconsolidated clays has mainly been restricted to field studies, with only a few generic numerical studies. Nonetheless, a large part of underground tunnel construction has happened and continues to occur in overconsolidated clays. The paper bridges this gap by using the case study of Waterloo International Terminal, where two new tunnels were excavated beneath two 70 year-old tunnels, to validate a numerical model. The validated numerical results provide new, valuable insights into the differences and similarities of the response of the existing tunnels depending on their typology (running or station tunnels) and on the time after the excavation of the new tunnels. Furthermore, they reveal the significance of the stiffness reduction factors that need to be applied to account for the segmental nature of the tunnel linings, highlighting the need for further research into the operational value of the tunnel stiffness.
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Journal articlePedro AMG, Taborda D, Repsold LM, et al., 2025,
The influence of the construction methodology on the modelled response of shafts
, Soils and Rocks, Vol: 48, Pages: 1-15, ISSN: 1980-9743Shaft excavation is essential in modern cities, allowing for quick and direct access to the underground, where most transportation networks and utilities are being installed to reduce surface congestion. Selecting the appropriate construction methodology is critical to minimize ground movements, while ensuring structural stability and construction efficiency. This study assesses the performance of three typical construction methodologies – Excavation Before Support (EBS), Support Before Excavation (SBE) and Dual-Lined Shafts (DLS) – through a comprehensive numerical study. The validation of the adopted modelling approach for each methodology is performed by simulating three case studies in close proximity to each other. Several aspects of numerical modelling are discussed, such as the simulation of the hardening behavior of the sprayed concrete, the modelling the wall installation and their stiffness anisotropy. For each methodology, the influence of key variables is assessed through parametric studies, highlighting the importance of the excavation step height, the lining thickness and the embedded length of the wall. A final study, where all methodologies are compared for the same ground conditions, is carried out for two shaft diameters. Results indicate that SBE produces the smallest ground movements but induces the highest lining forces. In contrast, EBS originates higher ground movements due to significant soil decompression but smaller lining forces. DLS methodology exhibits an intermediate behavior, although more similar to that observed in EBS. These findings emphasize the importance of selecting an adequate shaft construction methodology and provide valuable information regarding the appropriate numerical simulation of each technique.
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Journal articleMA S, Kontoe S, Taborda D, 2025,
Quantifying the variation of hydraulic conductivity during seismic liquefaction
, Soil Dynamics and Earthquake Engineering, Vol: 197, ISSN: 0267-7261Hydraulic conductivity plays a significant role in the evolution of liquefaction phenomena induced by seismic loading, influencing the pore water pressure buildup and dissipation, as well as the associated settlement during and after liquefaction. Experimental evidence indicates that hydraulic conductivity varies significantly during and after seismic excitation. However, most previous studies have focused on experimentally capturing soil hydraulic conductivity variations during the post-shaking phase, primarily based on the results at the stage of excess pore water pressure dissipation and consolidation of sand particles after liquefaction. This paper aims to quantify the variation of hydraulic conductivity during liquefaction, covering both the co-seismic and post-shaking phases. Adopting a fully coupled solid-fluid formulation (u–p), a new back-analysis methodology is introduced which allows the direct estimation of the hydraulic conductivity of a soil deposit during liquefaction based on centrifuge data or field measurements. Data from eight well-documented free-field dynamic centrifuge tests are then analysed, revealing key characteristics of the variation of hydraulic conductivity during liquefaction. The results show that hydraulic conductivity increases rapidly at the onset of seismic shaking but gradually decreases despite high pore pressures persisting. The depicted trends are explained using the Kozeny-Carman equation, which highlights the combined effects of seismic shaking-induced agitation, liquefaction, and solidification on soil hydraulic conductivity during the co-seismic and post-shaking phases.
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Conference paperImansyah MR, Taborda D, Hau KW, et al., 2025,
Numerical investigation of offshore foundation on liquefiable sands
, 20th International Conference: The Jack-up PlatformThis study investigates the seismic response of shallow foundations resting on liquefiable sand deposits, with theaim of providing insights into the expected behaviour of Wind Turbine Installation Vessels (WTIV) when subjected to earthquake loading. A detailed calibration strategy based on commonly available ground information is outlined for Nevada sand, with a detailed characterisation of the model performance being undertaken in termsof CSR, stiffness degradation, and damping ratio curves. Subsequent validation process is also provided bysimulating centrifuge experiments of footings resting on liquefiable deposits. Lastly, three-dimensional finiteelement analyses of a WTIV are performed employing the calibrated UBC3D-PLM parameters. The impact of soilliquefaction on the response of the WTIV is investigated, with particular emphasis given to the additionalsettlements caused by the seismic loading.
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Journal articleMaddah Sadatieh MS, Tsiampousi A, Paschalis A, 2025,
Numerical study of the effect of soil-plant-atmosphere interaction under future climate projections and different vegetation covers
, Geomechanics for Energy and the Environment, Vol: 43, ISSN: 2352-3808Soil-plant-atmosphere interaction (SPAI) plays a significant role on the safety and serviceably of geotechnical infrastructure. The mechanical and hydraulic soil behaviour varies with the soil water content and pore water pressures (PWP), which are in turn affected by vegetation and weather conditions. Focusing on the hydraulic reinforcement that extraction of water through the plant roots offers, this study couples advances in ecohydrological modelling with advances in geotechnical modelling, overcoming previous crude assumptions around the application of climatic effects on the geotechnical analysis. A methodology for incorporating realistic ecohydrological effects in the geotechnical analysis is developed and validated, and applied in the case study of a cut slope in Newbury, UK, for which field monitoring data is available, to demonstrate its successful applicability in boundary value problems. The results demonstrate the positive effect of vegetation on the infrastructure by increasing the Factor of Safety. Finally, the effect of climate change and changes in slope vegetation cover are investigated. The analysis results demonstrate that slope behaviour depends on complex interactions between the climate and the soil hydraulic properties and cannot be solely anticipated based on climate data, but suctions and changes in suction need necessarily to be considered.
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Conference paperMaddah Sadatieh MS, Tsiampousi A, Paschalis A, 2025,
IMPACT OF DEPTH DISTRIBUTED PLANT WATER UPTAKE ON SLOPE SAFETY
, The 9th Internation Symposium for Geotechnical Safety and Risk (ISGSR) in August 2025 -
Conference paperMaddah Sadatieh MS, Tsiampousi A, Paschalis A, 2025,
Modelling the impact of depth distributed plant water uptake on Soil-Plant-Atmosphere Interactions
, 5th European Conference on Unsaturated Soils and Biotechnology applied to Geotechnical Engineering (EUNSAT2025 with BGE), Publisher: EDP Sciences, ISSN: 2555-0403The soil-plant-Atmosphere interaction (SPAI) significantly influences the safety and serviceability of engineering infrastructure by affecting pore water pressure (PWP) distribution. Rainfall and water infiltration increase PWPs, reducing soil strength, while evapotranspirationa "driven by evaporation and plant transpirationa "induces negative pore pressures (suction), enhancing soil strength and safety. However, vegetation can also pose serviceability challenges. During summer, root water uptake causes soil shrinkage, and in wet months, infiltration induces swelling. These cyclic volume changes can disrupt infrastructure, leading to road and track delays or closures. Accurate modelling of SPAI is therefore critical to understanding the effects of climate change and vegetation on soil hydraulic and mechanical behaviour. This study examines how surface and internal flow boundary conditions affect SPAI modelling within a fully coupled flow-deformation framework. While most recent research has focused on surface boundary conditions for hydrological fluxes, this paper evaluates the inclusion of internal boundary conditions to simulate vegetation transpiration. A comparative analysis assesses the safety and serviceability outcomes for models employing only surface boundary conditions versus those incorporating both surface and internal conditions.
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Journal articleTaborda D, Pedro A, Xia H, et al., 2025,
A methodology for improved predictions of surface ground movements around shafts
, Proceedings of the Institution of Civil Engineers: Geotechnical Engineering, Vol: 178, Pages: 479-493, ISSN: 1353-2618Shafts are typically employed in urban environments to provide access or ventilation to underground structures such as stations, railways or highways. The choice of design is determined, among other things, by the need to control settlements at the surface, often estimated during early design stages using empirical expressions. These have been shown to have limited accuracy, failing to account appropriately for the effect of shaft diameter on the ground movements associated with shaft excavation. This paper reviews empirical expressions available in the literature in the context of a large database of settlements induced by shaft excavation in London. A comprehensive set of detailed numerical analyses is performed to enable the development of a new set of expressions capable of predicting accurately the computed vertical and horizontal ground movements at the surface. The new expressions are shown to provide better predictions of the observed field data than predictive expressions available in the literature, establishing a new benchmark against which future proposals can be assessed.
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Journal articleSanchez Fernandez J, Ruiz Lopez A, Taborda D, 2025,
A novel machine learning-based approach to thermal integrity profiling of concrete pile foundations
, Data-Centric Engineering, Vol: 6, ISSN: 2632-6736Thermal Integrity Profiling (TIP) is a non-destructive testing technique which takes advantage of the concrete heat of hydration (HoH) to detect inclusions during the casting process. This method is becoming more popular due to its ease of application, as it can be used to predict defects in most concrete foundation structures requiring only the monitoring of temperatures. Despite its advantages, challenges remain with regard to data interpretation and analysis, as temperature is only known at discrete points within a given cross-section. This study introduces a novel method for the interpretation of TIP readings using neural networks. Training data is obtained through numerical FE simulation spanning an extensive range of soil, concrete and geometrical parameters. The developed algorithm first classifies concrete piles, establishing the presence or absence of defects. This is followed by a regression algorithm that predicts the defect size and its location within the cross-section. Additionally, the regression model provides reliable estimates for the reinforcement cage misalignment and concrete hydration parameters. To make these predictions, the proposed methodology only requires temperature data in the form standard in TIP, and so it can be seamlessly incorporated within the TIP workflows. This work demonstrates the applicability and robustness of machine learning algorithms in enhancing non-destructive TIP testing of concrete foundations, thereby improving the safety and efficiency of civil engineering projects.
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Conference paperMaddah Sadatieh MS, Tsiampousi A, Paschalis A, 2025,
Numerical Analysis of Soil-Plant-Atmosphere Interaction
, The 4th PANAM UNSAT conference in June 2025 -
Conference paperProvost A, Sanchez Fernandez J, Sapin P, et al., 2025,
An approach for including heat pump performance in the design of thermo-active piles
, 3rd International Conference on Energy Geotechnics, Publisher: ISSMGEThe focus on sustainable built environment has grown with the drive for net-zero. The use of pile foundations and other geotechnical structures as ground heat exchangers (GHEs) is key to unlocking the economic viability of ground-source energy systems (GSESs) in dense urban areas. However, current design procedures characterise the performance of GHEs under a given temperature or heat flux, which consider the heat exchanger in isolation from the rest of the GSES. This study proposes a new method to assess the thermal performance of GHEs based on the electricity consumption of the heat pump byintroducing explicitly a model describing its performance based on operating temperatures. This general method is applied to a thermo-active pile, providing insights into the impact of pile diameter and length
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Conference paperSanchez Fernandez J, Provost A, Ruiz Lopez A, et al., 2025,
A data-driven approach to predicting the long-term thermal performance of thermo-active piles
, 3rd International Conference on Energy GeotechnicsThe analysis and optimisation of large ground source energy systems involving the use of thermo-active piles requires the ability to predict the thermal performance of these geothermal structures using limited computational resources, as many different configurations need to be tested. Current design methods are either based on empirical expressions, the accuracy of which is necessarily limited, or on thermo-hydraulic modelling which is computationally expensive and hence of difficult integration with optimisation procedures. In this paper, a surrogate model of a single thermo-active pile is established by running multiple thermo-hydraulic finite element analyses using different combinations of thermal ground properties, pipe arrangement, fluid temperature, pile length and pile diameter determined using a Latin hypercube sampling approach. The database of results is then used to train an artificial neural network (ANN), which is shown to produce accurate predictions of the thermal performance of a thermo-active pile given its characteristics and those of the surrounding ground. Given the low computational cost of surrogate models, this approach enables the design optimisation of large systems with greater confidence than previously possible using empirical relationships and a fraction of the resources required by thermo-hydraulic finite element models.
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Conference paperBeh M, Liu R, Taborda D, et al., 2025,
Numerical Modelling of Ground Improvement Thermal Parameters for Long-Term Energy Pile Performance
, 3rd International Conference on Energy Geotechnics
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