Periodic random fields to perform site response and liquefaction susceptibility analysis

Free-field site response analysis is a standard technique used to predict soil deposit dynamic response and liquefaction susceptibility. Such analyses are typically carried out by implementing periodic boundaries to guarantee the same speed of the dynamic waves travelling across them. However, when using random fields to consider the impact of...

Machine learning for prediction of undrained shear strength from cone penetration test data

This research focuses on investigating the relative performance of a range of machine learning algorithms, namely the artificial neural network, support vector machine, Gaussian process regression, random forest, and XGBoost, for predicting the undrained shear strength from cone penetration test data. This is to assess how machine learning could...

Predicting subsurface stratigraphy using an improved Coupled Markov Chain method

Geological uncertainty can significantly influence the computed response of a geotechnical structure. For example, ignoring the presence of a weak soil layer embedded within a stronger layer and assuming a deterministic stratigraphic boundary can significantly underestimate the probability of failure. In this paper, the coupled Markov chain...

Predicting subsurface classification in 2D from cone penetration test data

Uncertainty is inevitable in the characterisation of a geotechnical site, especially due to the inherently heterogeneous nature of the ground. In this paper, a method for characterising a subsurface with limited cone penetration test (CPT) data is proposed. The method is based on integrating predictions of CPT parameters with a probabilistic...

Reliability-Based Partial Factors Considering Spatial Variability of Strength Parameters

The stability of six regional dyke cross-sections in the Netherlands was re-assessed using the random finite element method (RFEM), which explicitly accounts for the spatial variability of strength parameters. The RFEM assessments of the cross-sections were shown to result in significantly narrower response distributions than those obtained...

Effect of uncertainties in geometry, inter-layer boundary and shear strength properties on the probabilistic stability of a 3D embankment slope

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...

Geotechnical uncertainties and reliability-based assessments of dykes

This thesis utilises the random finite element method (RFEM) to provide practical guidance and tools for geotechnical engineers to account for the influence of soil spatial variability. This has involved: (a) practical insight and guidance on the choice of characteristic soil property values and scales of fluctuation; (b) a robust approach to...

On characteristic values for calculating factors of safety for dyke stability

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...

Modified Semi-Analytical Method for 3D Slope Reliability

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...

An improved semi-analytical method for 3D slope reliability assessments

An improved semi-analytical method for calculating the reliability of 3D slopes with spatially varying shear strength parameters is proposed. The response of an existing semi-analytical method has been compared with that of the computationally more intensive, but more general, random finite element method (RFEM), demonstrating that the simpler...

On characteristic values and the reliability-based assessment of dykes

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...

3D slope stability analysis with spatially variable and cross-correlated shear strength parameters

The paper investigates the stability of slopes with spatially variable and cross-correlated shear strength parameters in 3D. The influence of various cross-correlation coefficients between these parameters on the probability of 3D slope failure has been considered for different levels of anisotropy of the heterogeneity in the shear strength....

Influence of Spatial Variability of Shear Strength Parameters on 3D Slope Reliability and Comparison of Analysis Methods

A 3D slope stability problem with spatially varying shear strength parameters has been analysed using the 3D random finite element method. This method links random fields of the random variables, in this case, cohesion and friction angle, with the finite element method within a Monte Carlo framework. The influence of spatial variability on...