Chris Clayton

Chris Clayton
University of Southampton · civl Engineering

About

208
Publications
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Introduction

Publications

Publications (208)
Article
This paper gives an overview of almost 3 years of monitoring data obtained from instrumentation installed in a 90 m long reinforced concrete integral bridge in South Africa. The main objective of this structural monitoring project was to assess the effect of environmental factors on integral bridge abutment movement, with specific focus on thermal...
Article
Full-text available
It is important to be able to measure stresses in tunnel linings to verify design assumptions and validate numerical models. For sprayed concrete-lined tunnels, continuous monitoring of stresses from the time of spraying onwards is desirable, and this can only be achieved using pressure cells installed on and in the sprayed concrete lining. Althoug...
Chapter
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When testing of stiff soil specimens using a Stokoe resonant column apparatus (RCA) the compliance of the apparatus significantly influences the derived stiffness of the soil [6]. In this paper, we present a simple mathematical model that takes into account equipment compliance, and therefore improving the accuracy in derivation of the small strain...
Article
Full-text available
Gas hydrates can form more or less at the same time as seafloor sediment. They can have the effect of significantly stiffening and strengthening deep-ocean sediments. Subsequent increases in situ temperature or decreases in pressure may trigger hydrate dissociation, leading to large reductions in the strength and stiffness of the sediment and possi...
Article
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This paper reports on an experimental study on the scouring of pipe materials on the outside of leaks caused by soil fluidization. A base experiment was designed consisting of a 3 mm diameter hole angled at 45° to the horizontal in a 110 mm diameter unplasticized polyvinyl chloride (uPVC) pipe. Five parameters were investigated in a sensitivity ana...
Conference Paper
Full-text available
Small-displacement pile driving in chalk produces an annulus of crushed and remoulded putty-like material through which shaft friction is believed to be mobilised. Ultimate shaft friction is assumed to be a function of the effective angle of friction of the putty chalk interface and the radial effective stress acting on the pile shaft. The mechanis...
Conference Paper
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The installation of displacement piles in chalk involves the crushing, remoulding and densifying of the material under the pile tip. This remoulded material forms an annulus around the installed pile. Shaft friction can be expected to be significantly affected by the characteristics of this annulus. However, research on its attributes and the mecha...
Article
The stress changes experienced by soil below a railway line as trains pass are complex, involving a combination of compression and shear. Laboratory hollow cylinder tests were carried out to investigate the response of soils of different clay content to these stress changes. As the load is cycled, the build-up of pore-water pressures within the soi...
Article
Methane gas recovery from gas hydrate–bearing sands requires dissociation of the hydrate. Understanding changes in the stiffness of the sand is essential if future production scenarios are to be modelled realistically. This paper reports the results of resonant column tests conducted to measure changes in shear and flexural Young’s modulus (stiffne...
Article
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This paper presents the results of a series of hollow cylinder tests carried out to investigate the role of drainage conditions on the response of railway track foundation materials during cyclic loading. Three sand–clay mixes were tested. It was found that, below a certain cyclic shear stress threshold, and depending on the drainage conditions, ch...
Article
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The Atlantic Frontier Environmental Network (AFEN) submarine slide complex is located 95 km NW of the Shetland Islands, at a water depth of c. 1000 m. It is thought to have occurred some 2800 years ago. The slide complex is c. 4 km wide and 13 km in length, and lies on a shallow slope, between 0.7 and 2.5°. Previous sampling and laboratory testing...
Conference Paper
Full-text available
Quantifying the effect of gas hydrates on engineering properties of sediments is essential to assess its role as triggering mechanism for submarine slope instabilities, potential energy resource or accelerating climate change. Previous studies show cementation due to presence of gas hydrate in deep ocean sediments or permafrost influences the seism...
Article
The formation and dissociation of methane hydrate within sediment can lead to large changes in wave velocities, which provide valuable insights into the processes involved in hydrate formation. These are of practical importance in geophysical characterisation, as well developing strategies for the future exploitation of methane hydrates. This paper...
Article
Full-text available
The estimation of maximum travel distance of flow slides is an important topic to assess the consequence of natural disasters caused by landslides. During debris transportation, dissipation rules of pore-water pressure determine movement properties of flow slides. Based on 1-D Terzaghi consolidation theory, expressions of excess pore-water pressure...
Article
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Internal fluidization, the process whereby granular soil is transformed into a fluid-like state when liquid or gas is pumped into it, is of importance in a number of civil and geotechnical engineering processes, for example pipe leakage, flow through sheet piling, pile jetting, and spudcan extraction. This paper draws together the limited literatur...
Conference Paper
Soil element testings on the sand grains could result in successive drops in stress-strain relationships. These successive drops and formations give a stick-slip nature to the fluctuations, which might be attributed mainly to the jamming through particles, rate of loading, effective stress, pore fluid characteristics, and the compliance in the appa...
Article
The lack of correlation between test data on laboratory synthesised hydrate-bearing sediments has raised questions as to the interaction between the hydrate and the host sediment. The development of the Pressure Core Analysis and Transfer System (PCATS) has enabled the recovery of pressurised cores in liners and their subsequent transfer into other...
Article
Stiffness parameters are required for many geotechnical calculations, including numerical modelling using the finite element or finite difference methods. The measurement of stiffness is not trivial, yet the actual values of stiffness adopted during analyses can have a very significant impact on predictions, and hence the perceived viability of a p...
Article
Full-text available
Undisturbed sampling of gold tailings, especially under the water table, is difficult and in many cases impossible. For this reason laboratory testing of tailings is generally conducted on reconstituted material. It has been shown that laboratory sample preparation methods can affect the mechanical behaviour of cohesionless soil and it is generally...
Article
This paper provides the background to the 50th Rankine Lecture. It considers the growth in emphasis of the prediction of ground displacements during design in the past two decades of the 20th century, as a result of the lessons learnt from field observations. The historical development of the theory of elasticity is then described, as are the const...
Article
Full-text available
The monitoring of aerosol concentrations comprises a high environmental priority, particularly in urban areas. Remote sensing of atmospheric aerosol optical thickness (AOT) could be used to assess particulate matter levels at the ground. However, such measurements often need further validation. In this study, aerosol data retrieved from satellite a...
Article
This paper describes unusual stress–strain behaviour, involving deviatoric stress, axial strain and pore pressure jumps, observed during undrained triaxial compression testing of Leighton Buzzard sand when using syrup and silicon oil pore fluids. The materials, pore fluids, specimen preparation and test methods are described, as are the results of...
Article
Full-text available
Solar radiation reflected by the Earth's surface to satellite sensors is modified by its interaction with the atmosphere. The objective of applying an atmospheric correction is to determine true surface reflectance values and to retrieve physical parameters of the Earth's surface, including surface reflectance, by removing atmospheric effects from...
Article
Cementing of sediment occurs naturally in many soils and weak rocks, during both the early and late stages of diagenesis. This paper reports the results of a series of resonant column tests carried out on a range of sand-sized geomaterials to explore the effects of different hydrate cement morphologies on the very small strain stiffness of the mate...
Article
While many physical experimental methods have been developed to produce different relative densities, and to measure the minimum and maximum void ratios of samples of granular soil, there has been little exploration of techniques for varying the initial void ratio of numerical (e.g. DEM) ‘samples'. This paper reports a series of numerical experimen...
Article
Many geotechnical processes, for example pile driving, penetration testing, sampling and various in-situ stress measurement techniques, involve the penetration of an object into the soil. This paper presents the results of two-dimensional numerical analyses carried out to determine the stress-strain response of a soil caused by the penetration of a...
Article
This paper provides a written version of a Keynote Presentation made at the 10th International Congress of the Association for Engineering Geology and the Environment (IAEG), held in Nottingham in September 2006. It identifies the objectives of site investigation, as stated in the British Standard. It then reviews the difficulties that face the inv...
Article
Full-text available
The methods routinely used for the determination of particle-size distribution of soils were introduced about a century ago and have changed little in the intervening period. In other areas, such as chemical and process engineering and sedimentology, there has been considerable development of automated apparatus. This paper presents a critical revi...
Article
Because atmospheric effects can have a significant impact on the data obtained from multi-spectral satellite remote sensing, it is frequently necessary to make corrections before any other image processing can be started. This paper describes a robust and relatively simple atmospheric correction method that uses pseudo-invariant targets (PITs) in c...
Article
Print ISSN: 1747-6585 A timely low-cost method providing information on water quality and trophic state to various users of reservoir or dam water is a must. Conventional methods involved tedious and expensive in situ and laboratory studies. Satellite-borne sensors have the capability of providing repetitive, low-cost, multispectra, timely and reli...
Article
A realistic assessment of the whole life cost of rail track foundations requires analysis of the effects of the repeated loadings applied by trains. This paper reports the effects of principal stress rotation (PSR) during cyclic loading on the permanent deformations measured in a series of hollow cylinder tests. The tests were carried out on a numb...
Article
The methods routinely used for the determination of particle-size distribution of soils were introduced about a century ago and have changed little in the intervening period. In other areas, such as chemical and process engineering and sedimentology, there has been considerable development of automated apparatus. This paper presents a critical revi...
Article
In the companion paper we noted that a significant body of literature exists to suggest that form can have an important influence on the behaviour of an assembly of particles during shear, and that at present there are no practical methods of measuring form. A simple definition of form was adopted, and a method of measuring form was proposed for co...
Article
A small but important body of geomechanics literature now exists to show qualitatively that whether a specimen is composed of particles that are bulky or platy can have a significant effect on its behaviour during compression and shear. This particle shape characteristic has been termed 'form', which has sometimes been estimated on the basis of 'sp...
Article
This paper reports the results of a series of analyses, and physical and numerical experiments, carried out in order to investigate the effects of apparatus stiffness and mass, and specimen fixity, on the results obtained from fixed-free resonant column testing. It is shown that the stiffness of the drive head and the mass of the apparatus base can...
Conference Paper
Full-text available
This paper explores the beneficial integration of both satellite remote sensing and in-situ spectroradiometric measurements for improving the available post-processing techniques in monitoring landscape changes in the vicinity of archaeological sites. The study has been conducted in the Kato Paphos archaeological area in the Paphos District area in...
Conference Paper
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This paper describes the results obtained by the direct comparison between the visibility values obtained from satellite remotely sensed data and ground measurements in an area of interest near the Paphos International Airport in Cyprus. During the satellite overpasses, visibility values are obtained from the nearby airport and sun-photometer measu...
Conference Paper
Full-text available
Bearing in mind that the atmospheric effects are mainly caused by scattering and absorption of atmospheric gases, aerosol and clouds, the most important point in order to perform an atmospheric correction is to be aware of the optical characteristics of the atmosphere. These optical characteristics can be found from different sources such as the ge...
Article
This paper describes some recent and current research on the behaviour of railway track. The main focus is on the deflections of the track as trains pass, and how these may be linked to the stress paths experienced by the ballast and the underlying sub-base. Three questions are addressed: (1) what are the stress paths that soil elements below a rai...
Article
This study uses the psychological framework of ‘mental modelling’ to compare what experts and laypeople think about the hardness of drinking water. A drinking-water quality mental model was developed using influence-directed network procedures. This was evaluated in qualitative studies in Oxfordshire and the findings revealed gaps in laypeople's kn...
Article
The design of railway track formations has traditionally been empirically rather than analytically based, with ballast and sub-ballast layer thicknesses specified mainly on the basis of previous practice. Recent design methods are more scientifically based, and for the most advanced design methods currently in use, input parameters are typically de...
Conference Paper
Full-text available
Urban air quality has traditionally been monitored with networks of ground monitoring stations and the use of models that evaluate emissions and predict changes in air quality at discrete points. The increasing availability of earth observing satellite systems together with advances in digital image processing techniques provide a new avenue to mon...
Article
A wide variety of instrumentation was deployed during the construction of the sprayed-concrete lined tunnels at Heathrow Express Terminal 4 station. This paper presents data from the in-tunnel displacement monitoring system and for settlements above the tunnels, providing data on instrument survival and performance, and an overall summary of the di...
Conference Paper
Various numerical methods have been employed to determine soil deformations around penetrating objects. However, due to the extensive computational resource requirements for 3D analysis, soil deformations are usually estimated from 2D analysis. The adequacy of estimating soil deformations around a 3D penetrating object with a 2D plane-strain analys...
Article
Significance of the railway formation, track formation structure and their design performance in future are discussed. Significance of the railway formation include: earthworks construction comprises that more than half of the total track expenditure in the construction, majority of speed restrictions on a heavy haul line are related to poor perfor...
Article
Most design methods for railway trackbed - ballast, sub-ballast and formation - are empirical or recipe-based. Coupled with the lack of a detailed understanding of how loads are transmitted through the track system into the soil, it is not surprising that the importance of the sub-ballast and formation is usually underestimated. Research at the Uni...
Conference Paper
Push-in pressure cells are commonly used in the UK to measure in-situ stress. In common with all direct measurement techniques, the stress state of the soil is altered as the cell is advanced into the ground. This leads to an overestimate in the magnitude of the in-situ stress measured by the cells. In this paper, the existing approaches for interp...
Conference Paper
Full-text available
This paper investigates the potential of using Geographical Information Systems (GIS) and Satellite Remote Sensing (SRS) to support the high voltage electricity network in Cyprus. The current high voltage electricity network is located all over Cyprus and the location of such lines is critical for the development and design of major and minor infra...
Article
Although satellite remote sensing techniques have been widely implemented for a variety of applications, using either single or time-series images, few studies have explicitly considered atmospheric effects, and how they can most effectively be minimized. Despite the considerable number of available atmospheric correction algorithms, there is littl...
Article
The prediction of the settlements of spread foundations on in-situ chalk is best carried out using empirical methods, based on the simple behavioural model developed by Burland & Lord (1970) using results from plate tests. However, the data available to support this approach remain somewhat limited, stratigraphically, geographically and in terms of...
Article
Full-text available
The determination of realistic values of stiffness and in-situ horizontal stress is challenging in softer materials, but in weak rocks where discontinuities are typically present it is particularly difficult. Such difficulties were encountered during the site investigation for the construction of the A444 Coventry North-South road retaining structu...
Article
Full-text available
The determination of realistic values of stiffness and in-situ horizontal stress is challenging in softer materials, but in weak rocks where discontinuities are typically present it is particularly difficult. Such difficulties were encountered during the site investigation for the construction of the A444 Coventry North-South road retaining structu...