Searched for: subject:"spatial%5C+variability"
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van Koelen, Tim (author)
The subsurface is often modelled as multiple homogeneous soil layers. In reality, the soil properties of these layers are heterogeneous and spatially variable, making it difficult to properly deduct the engineering properties that are required in the design of geotechnical structures. This leads to uncertainty in the design. The probabilistic...
master thesis 2019
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Hicks, M.A. (author), Varkey, D. (author), van den Eijnden, A.P. (author), de Gast, T. (author), Vardon, P.J. (author)
A case study involving the assessment and re-design of an existing dyke, founded on a layered soil, has compared deterministic analysis based on 5-percentile property values and a reliability-based random finite element analysis consistent with the requirements of Eurocode 7. The results show that a consideration of the spatial nature of soil...
journal article 2019
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Remmers, J. (author), Reale, C. (author), Pisano, F. (author), Raymackers, Sylvie (author), Gavin, Kenneth (author)
This study presents a probabilistic analyses of suction bucket installation in cohesionless soils. The spatial variability of soil properties is quantified using a representative survey dataset from practice. Vertical random field modelling is used to model cone resistance variability and probability density functions are fitted using drained...
journal article 2019
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Liu, K. (author), Vardon, P.J. (author), Hicks, M.A. (author)
A data assimilation framework, utilising measurements of pore water pressure to sequentially improve the estimation of soil hydraulic parameters and, in turn, the prediction of slope stability, is proposed. Its effectiveness is demonstrated for an idealised numerical example involving the spatial variability of saturated hydraulic...
journal article 2018
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Prendergast, L.J. (author), Reale, C. (author), Gavin, K. (author)
The trend for development in the offshore wind sector is towards larger turbines in deeper water. This results in higher wind and wave loads on these dynamically sensitive structures. Monopiles are the preferred foundation solution for offshore wind structures and have a typical expected design life of 20 years. These foundations have strict...
journal article 2018
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Liu, K. (author), Vardon, P.J. (author), Hicks, M.A. (author), Arnold, P. (author)
The stability of most earth embankments is strongly influenced by the water content of the soil. The water content directly influences the suction or pore pressure in the soil, as well as the mass of material, thereby affecting the stress state and strength, and leading to changes in the stability. These aspects are coupled by the so-called soil...
journal article 2017
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Li, Y. (author), Hicks, M.A. (author), Vardon, P.J. (author)
A method of combining 3D Kriging for geotechnical sampling schemes with an existing random field generator is presented and validated. Conditional random fields of soil heterogeneity are then linked with finite elements, within a Monte Carlo framework, to investigate optimum sampling locations and the cost-effective design of a slope. The...
journal article 2016
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Vardon, P.J. (author), Liu, K. (author), Hicks, M.A. (author)
The determination of slope stability for existing slopes is challenging, partly due to the spatial variability of soils. Reliability-based design can incorporate uncertainties and yield probabilities of slope failure. Field measurements can be utilised to constrain probabilistic analyses, thereby reducing uncertainties and generally reducing...
journal article 2016
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Dong, J. (author), Steele-Dunne, S.C. (author), Ochsner, Tyson E. (author), van de Giesen, N.C. (author)
This study addresses two critical barriers to the use of Passive Distributed Temperature Sensing (DTS) for large-scale, high-resolution monitoring of soil moisture. In recent research, a particle batch smoother (PBS) was developed to assimilate sequences of temperature data at two depths into Hydrus-1D to estimate soil moisture as well as...
journal article 2016
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Nishimura, S-I. (author), Shibata, T. (author), Shuku, T. (author)
The spatial distribution of the strength inside an earth-fill dam is identified by sounding tests. In this research, the Swedish Weight Sounding (SWS) test is employed, and the spatially high-density test is possible to identify the spatial correlation structure by the SWS. The correlation structure of an earth-fill could be identified...
conference paper 2015
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Schöbi, R. (author), Sudret, B. (author)
In geotechnical applications, mechanical properties of soil vary spatially within the soil mass and they are often represented by random fields. When data at certain locations of the soil mass are available, conditional random fields may be used to incorporate them. In this paper, we combine conditional random fields with sparse polynomial chaos...
conference paper 2015
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Thajeel, J. (author), Al-Bittar, T. (author), Ahmed, A. (author), Soubra, A-H. (author)
The failure probability of geotechnical structures with spatially varying soil properties is generally computed using Monte Carlo simulation (MCS) methodology. This approach is well known to be very time-consuming when dealing with small failure probabilities. One alternative to MCS is the subset simulation approach. This approach was mainly...
conference paper 2015
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Daryani, K.E. (author), Mohamad, H. (author)
This paper studies the effect of soil spatial variability on bearing capacity of shallow foundations. The stochastic soil property is the undrained shear strength considered as a non-Gaussian random variable. The random variable is simulated using Local Average Subdivision Method. A Monte Carlo simulation approach is followed in combination with...
conference paper 2015
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Nie, X. (author), Zhang, J. (author), Huang, H. (author), Liu, Z. (author), Lacasse, S. (author)
In the past few years, random field theory has been increasingly used to model the inherent soil variability. The scale of fluctuation is one of the important parameters describing a stationary random field. In this study, the factors affecting an accurate estimation of the scale of fluctuation were studied with numerical experiments to show how...
conference paper 2015
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Zhang, L. (author), Yan, W.M. (author)
Soil slopes are generally unsaturated in which the soil-water characteristic curve (SWCC) plays an important role in its hydro-mechanical response. The commonly used Mohr-Coulomb failure criterion in saturated soil mechanics could be extended to take SWCC into account which is then able to determine the shear strength of unsaturated soil. Like...
conference paper 2015
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Effati Daryani, M.B. (author), Bahadori, H. (author), Daryani, K.E. (author)
The paper contrasts results obtained by the partially factored limit state design method and a more advanced Random Finite Difference Method (RFDM) in a benchmark problem of slope stability analysis with random undrained shear strength parameter. Local Average Subdivision method was used to simulate a non-Gaussian random variable. The key...
conference paper 2015
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Jiang, S. (author), Li, D. (author), Wei, B. (author)
The effect of probability distributions on the slope reliability is highlighted in this study since the lognormal distribution is often used to characterize the variability of soil properties to avoid negative values. A multiple response-surface based MCS method for slope reliability analysis in spatially variable soils is proposed. A...
conference paper 2015
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Lundberg, A.B. (author), Li, Y. (author)
A full geotechnical risk analysis includes site investigation, model simplification and analysis. The site characterization forms the basis for the choice of the soil parameters used in the subsequent analysis, but the soil data is normally analyzed with crude methods that do not include the effect of the soil variability. A case study is here...
conference paper 2015
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Low, B.K. (author)
Spatial autocorrelation arises in geological material by virtue of its formation by natural processes acting over long geologic time (millions of years). This endows geomaterial with some unique statistical features (e.g. spatial variability) not commonly found in structural material manufactured under strict quality control. For example, by the...
conference paper 2015
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De Visser, M.M. (author), Kanning, W. (author), Koopmans, R. (author), Niemeijer, J. (author)
Research to the failure mechanism piping (internal, backward erosion) in the Netherlands shows that the dikes require costly berms to meet the required safety standards. According to the Sellmeijer piping-formula, the d70 (70%-quantile of the grain size distribution by weight) is an important parameter in the resistance against piping. Therefore...
conference paper 2015
Searched for: subject:"spatial%5C+variability"
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