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Golchin, A. (author), Vardon, P.J. (author), Hicks, M.A. (author)The formulation of a new thermo-mechanical constitutive model consistent with the principles of thermodynamics is presented. The model is capable of predicting the rate-independent thermo-mechanical behavior of fine-grained soils. The constitutive equations are derived by defining only a Gibbs-type free energy and a dissipation potential, in...journal article 2022
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Golchin, A. (author), Vardon, P.J. (author), Hicks, M.A. (author)The formulation of a two surface/bubble thermo-mechanical constitutive model consistent with the principles of thermodynamics is presented. This allows plastic deformations inside the outer yield surface, resulting in a smooth stress–strain prediction and progressive cyclic deformations. This is achieved by the translation of the inner yield...journal article 2022
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Varkey, D. (author), Hicks, M.A. (author), Vardon, P.J. (author)This paper investigates the influence of three forms of uncertainty on the probabilistic stability of an idealised 3D embankment slope. These are: 1D spatial variability in the external geometry of the slope along its length, 2D spatial variability in the depth of the boundary between the embankment material and the foundation layer, and 3D...journal article 2022
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Li, Yajun (author), Li, Jianguang (author), Xu, Nengxiong (author), Fenton, Gordon A. (author), Vardon, P.J. (author), Hicks, M.A. (author)Correlation length or scale of fluctuation (SOF) is often used as a primary parameter in defining the spatial correlation characteristics of varying soil properties. However, geotechnical site investigations are rather limited so that proper determination of correlation length is not always possible. The concept of a worst-case correlation...journal article 2022
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Study of landslides and soil-structure interaction problems using the implicit material point methodGonzalez Acosta, J.L. (author), Vardon, P.J. (author), Hicks, M.A. (author)Mesh based methods such as the finite element method (FEM) are the most usually used techniques for analysing soil-structure interaction problems in geotechnical engineering. Nevertheless, standard FEM is unable to simulate large deformations and contact, hindering the realistic simulation of rotational, sliding, pull-out and overturning...journal article 2021
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Remmerswaal, G. (author), Vardon, P.J. (author), Hicks, M.A. (author)Due to a lack of large deformation dyke assessment models, primary failure mechanisms, such as inner slope failure, are often used as a proxy to assess the probability of failure of a dyke. However, a dyke continues to fulfil its main function unless, or until, flooding occurs. The Random Material Point Method (RMPM) is used here to investigate...journal article 2021
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van den Eijnden, A.P. (author), Schweckendiek, T. (author), Hicks, M.A. (author)A kriging-based metamodelling approach for analysing the structural reliability of a sheetpile wall in a dyke is formulated. This specific problem is characterised by high target reliabilities ((Formula presented.)) in combination with a noisy and incomplete numerical model response. Starting from the original formulation of active learning...journal article 2021
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de Gast, T. (author), Vardon, P.J. (author), Hicks, M.A. (author)Soil spatial variability has a significant impact on the reliability of geotechnical structures. In particular, the horizontal variability is important for linear infrastructure, which has only limited vertical height and width, but extensive length. Due to depositional and geological processes, the variability is often substantially...journal article 2021
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Zheng, X. (author), Pisano, F. (author), Vardon, P.J. (author), Hicks, M.A. (author)This paper presents a single-point Material Point Method (MPM) for large deformation problems in two-phase porous media such as soils. Many MPM formulations are known to produce numerical oscillations and inaccuracies in the simulated results, largely due to numerical integration and stress recovery performed at non-ideal locations, cell...journal article 2021
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Golchin, A. (author), Vardon, P.J. (author), Coombs, William M. (author), Hicks, M.A. (author)This paper presents a new Modified Cam Clay (MCC) type yield function, that is designed for robust and efficient use with implicit stress integration algorithms. The proposed yield function attains non-elliptical (e.g. tear and bullet) shapes, as well as the typical elliptical shape of the MCC model. Like that of MCC, and unlike most other...journal article 2021
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Gonzalez Acosta, J.L. (author), Vardon, P.J. (author), Hicks, M.A. (author)An implicit contact algorithm for the material point method (MPM) has been developed to simulate contact. This allows recently developed implicit MPM codes to simulate large-scale deformations and interaction with external bodies. The performance of the method has been investigated and compared to an existing explicit method using benchmark...journal article 2021
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Zheng, X. (author), Gonzalez Acosta, J.L. (author), Remmerswaal, G. (author), Vardon, P.J. (author), Pisano, F. (author), Hicks, M.A. (author)The material point method (MPM) shows promise for the simulation of large deformations in history-dependent materials such as soils. However, in general, it suffers from oscillations and inaccuracies due to its use of numerical integration and stress recovery at non-ideal locations. The development of a hydro-mechanical model, which does not...conference paper 2021
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Pan, Yutrao (author), Hicks, M.A. (author), Broere, W. (author)Artificial barriers are widely used to prevent leakages. However, due to construction errors during the wall installation, passages with small dimensions may occasionally penetrate through the barrier, undermining its tightness. A three-dimensional discretized algorithm (TDA) is proposed for quantitatively estimating the transient-state...journal article 2021
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Golchin, A. (author), Vardon, P.J. (author), Hicks, M.A. (author), Coombs, William M. (author), Pantev, I.A. (author)The numerical implementation of a recently developed thermomechanical constitutive model for fine-grained soils based on hyperelasticity-hyperplasticity theory (Golchin et al. 2020), is presented. A new unconventional implicit stress return mapping algorithm, compatible with elasticity derived from Gibbs (complementary) energy potential, in...conference paper 2021
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Maghsoudloo, A. (author), Askarinejad, A. (author), de Jager, R.R. (author), Molenkamp, F. (author), Hicks, M.A. (author)Planning a monitoring campaign for a natural submarine slope prone to static liquefaction is a challenging task due to the sudden nature of flow slides. Therefore, gaining a better insight by monitoring the changes in pore pressure and acceleration of the soil mass, prior to and at the onset of static liquefaction, of submerged model slopes...journal article 2021
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de Gast, T. (author), Hicks, M.A. (author), van den Eijnden, A.P. (author), Vardon, P.J. (author)A reliability-based analysis framework, accounting for uncertainty arising from the spatial variability of soil properties, has been validated for the controlled, well-instrumented slope failure of an historic dyke in the Netherlands. Using soil property statistics derived from the results of laboratory and cone penetration test (CPT) data for...journal article 2020
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Varkey, D. (author), Hicks, M.A. (author), van den Eijnden, A.P. (author), Vardon, P.J. (author)Various simplified approaches are used to calculate the characteristic values of shear strength properties, which have then been used in deterministic stability analyses of a dyke cross-section. The calculated factors of safety are compared with the 5-percentile ‘system response’ of the dyke cross-section, calculated using the more exhaustive...journal article 2020
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Remmerswaal, G. (author), Hicks, M.A. (author), Vardon, P.J. (author)The material point method (MPM) is used to model both rotational and horizontal sliding failure mechanisms of dykes under external (water) loading. To model the different failure mechanisms, an external hydrostatic water pressure has been applied on the canal side of the dyke by applying a newly developed boundary condition. The boundary...conference paper 2019
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Duvvuru Mohan, V.K. (author), Vardon, P.J. (author), Hicks, M.A. (author), van Gelder, P.H.A.J.M. (author)Bayesian networks are proposed as a tool to integrate reliability and influential variables relating to the slope stability of an idealized embankment. The site investigation (extent) and slope geometry, as well as the material properties and their spatial variability, are considered within a Bayesian network. The random finite element method ...conference paper 2019
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Varkey, D. (author), Hicks, M.A. (author), Vardon, P.J. (author)An improved method for the reliability analysis of 3D slopes has been proposed based on the semi-analytical method of Vanmarcke (1977). Comparing the predicted responses of an idealised 3D slope obtained by the more general, albeit computationally intensive, random finite element method (RFEM), and the original semi-analytical method showed that...conference paper 2019