International Journal of Physical Modelling in Geotechnics, 2003
Presented in this paper are measurements from five different laboratories with four different pro... more Presented in this paper are measurements from five different laboratories with four different probes to determine the moisture content of sand samples in flight on a geotechnical centrifuge. The sensors are resistivity probes, capacitance probes, TDR sensors and Geiger Müller tubes. Experiments were carried out with a sand-water-air system, resistivity probes and TDR sensors were additionally tested in the sand-water-NAPL system. All probes were fast responding and gave reliable and reproducible results during centrifuge tests at up to 40 g. The work presented in this paper was carried out as part of the NECER programme funded by the European Commission.
In recent years the use of physical modelling aboard large centrifuges has been considerably exte... more In recent years the use of physical modelling aboard large centrifuges has been considerably extended in many areas of geotechnical research. In offshore and coastal engineering, where loadings on structures are often complex and non-static, such models have been widely used and are believed to have given considerable qualitative insights into the modes of behaviour of a number of different structural forms on both uniform and stratified soil deposits, as well as yielding quantitative data for performance predictions which add to the confidence of designers, operators, insurers and regulatory agencies. Perhaps surprisingly, the mobile jack-up structure has only recently been the subject of model studies of this type. Such studies as have been carried out are very preliminary and the present paper aims to add to these and consider possible areas of useful future extension.
International Journal of Physical Modelling in Geotechnics, 2015
Although the concept of using a centrifuge to model engineering structures arose in the nineteent... more Although the concept of using a centrifuge to model engineering structures arose in the nineteenth century, the practice began only in the 1930s, in America and Russia. This paper provides details of the careers of four pioneers, primarily in the period prior to 1945 – Bucky, Davidenkov, Fedorov and Pokrovsky. There is some discussion on the effects of dissemination of Russian work on practice in the USA and elsewhere following the disclosure of Pokrovsky's work at the time of the 1973 International Conference on Soil Mechanics and Foundation Engineering (ICSMFE) in Moscow. Physical modelling using centrifuges continues to be considered as one of the most efficient experimental methods for research into the behaviour of soil constructions.
Prefabricated bituminous surfacing was developed during World War II to meet the need for rapid c... more Prefabricated bituminous surfacing was developed during World War II to meet the need for rapid construction of roads and runways in the military context. It was made from bitumen and hessian and commonly referred to as 'bithess'. The roots of this development are presented, along with a review of its usage during this conflict, with reflections on further developments after 1945. This form of construction found little use subsequently, being displaced by other geosynthetic developments, but could still have a role in developing countries. Ground Improvement Volume 168 Issue GI2 The use of prefabricated bituminous surfacing geosynthetic in World War II and beyond Craig, Gallagher and Wang
Proceedings of the Institution of Civil Engineers - Geotechnical Engineering, 1998
j Outline results are presented from a single experiment in which a 1:100 linear scale model of a... more j Outline results are presented from a single experiment in which a 1:100 linear scale model of a spud-can foundation was loaded on a strati®ed foundation alongside a group of tubular piles. The loading sequence simulated initial landing, static preload proof testing consistent with the usual offshore philosophy for accommodating anticipated in-service cyclic load combinations, through to ®nal removal, of an offshore jackup rig alongside an existing structure.
The adsorption process is largely a surface-action phenomenon. In this study, sorption capacities... more The adsorption process is largely a surface-action phenomenon. In this study, sorption capacities for heavy metals on a solid waste matrix were investigated. Five heavy metals (iron, copper, zinc, nickel and cadmium) were chosen because of their availability in any landfill site. The conditions during all the experimental runs were pH 7.0, temperature 32 • C and suppressed microbial degradation. For adsorption isotherm (Freundlich and Langmuir) calculations, fixed quantities of heavy metal ions were mixed with variable quantities of solid waste. The ratio of mass of adsorbate per unit mass of adsorbent was changed five times, by changing only the adsorbent amount. The results showed that the time required to reach equilibrium varied from metal to metal but all reached equilibrium within the first 32 h. The relative potential of sorption of the individual metals and mixed metals on the solid waste matrix is Fe > Zn > Cu > Ni > Cd. The sorption capacity of domestic solid waste matrix for heavy metals is quite significant and this property might prove helpful for the in situ removal of heavy metals in landfill operation.
International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1990
Winkler soil model was also carried out. Analytical results for pile strain distribution and surf... more Winkler soil model was also carried out. Analytical results for pile strain distribution and surface displacements compared reasonably well with measured values. 906357 Analysis of pile groups with variable shnft-ioad over point-load ratios. Technical note Ciemente, J L M
A critical review is presented which draws together results from model tests and computations on ... more A critical review is presented which draws together results from model tests and computations on the mechanisms by which the spud-can foundation of an independent leg offshore jack-up structure can penetrate deeply into the seabed through both uniform and stratified deposits. Particular consideration is given to the so-called punch-through mode in layered soil profiles, where a strong stratum overlies a weaker one. Little evidence has been found to support the mechanical basis of two methods of analysis commonly used in the offshore industry where foundations often have dimensions in excess of 10 m while conventional laboratory models have rarely exceeded 100 mm. New model tests performed in a centrifuge with stresses appropriate to offshore foundations are reported and these show different mechanisms from many unit gravity models. The need for a reappraisal of the basis of analysis is established. Where large volumes of soil are displaced by spud-can preloading, offshore analysis s...
A series of centrifuge model tests, at acceleration levels of 105 g, is reported, in which loosel... more A series of centrifuge model tests, at acceleration levels of 105 g, is reported, in which loosely placed vertical sand columns and densified sand columns have been used to improve the performance of oil storage tank foundations. A simulated tank of 34 m diameter, with a flexible base, has been subjected to incremental fluid loadings typically to 160 kPa, with foundation drainage permitted. Model preparation included the installation of as many as 572 sand columns in a single foundation. Comparison is made between the experimental results and the analysis of Priebe, which indicates that that analysis will overestimate the improvements if three-dimensional considerations are not taken into account. Comments are also included as to the extent to which model column formation may be deficient.
International Journal of Physical Modelling in Geotechnics, 2003
Presented in this paper are measurements from five different laboratories with four different pro... more Presented in this paper are measurements from five different laboratories with four different probes to determine the moisture content of sand samples in flight on a geotechnical centrifuge. The sensors are resistivity probes, capacitance probes, TDR sensors and Geiger Müller tubes. Experiments were carried out with a sand-water-air system, resistivity probes and TDR sensors were additionally tested in the sand-water-NAPL system. All probes were fast responding and gave reliable and reproducible results during centrifuge tests at up to 40 g. The work presented in this paper was carried out as part of the NECER programme funded by the European Commission.
In recent years the use of physical modelling aboard large centrifuges has been considerably exte... more In recent years the use of physical modelling aboard large centrifuges has been considerably extended in many areas of geotechnical research. In offshore and coastal engineering, where loadings on structures are often complex and non-static, such models have been widely used and are believed to have given considerable qualitative insights into the modes of behaviour of a number of different structural forms on both uniform and stratified soil deposits, as well as yielding quantitative data for performance predictions which add to the confidence of designers, operators, insurers and regulatory agencies. Perhaps surprisingly, the mobile jack-up structure has only recently been the subject of model studies of this type. Such studies as have been carried out are very preliminary and the present paper aims to add to these and consider possible areas of useful future extension.
International Journal of Physical Modelling in Geotechnics, 2015
Although the concept of using a centrifuge to model engineering structures arose in the nineteent... more Although the concept of using a centrifuge to model engineering structures arose in the nineteenth century, the practice began only in the 1930s, in America and Russia. This paper provides details of the careers of four pioneers, primarily in the period prior to 1945 – Bucky, Davidenkov, Fedorov and Pokrovsky. There is some discussion on the effects of dissemination of Russian work on practice in the USA and elsewhere following the disclosure of Pokrovsky's work at the time of the 1973 International Conference on Soil Mechanics and Foundation Engineering (ICSMFE) in Moscow. Physical modelling using centrifuges continues to be considered as one of the most efficient experimental methods for research into the behaviour of soil constructions.
Prefabricated bituminous surfacing was developed during World War II to meet the need for rapid c... more Prefabricated bituminous surfacing was developed during World War II to meet the need for rapid construction of roads and runways in the military context. It was made from bitumen and hessian and commonly referred to as 'bithess'. The roots of this development are presented, along with a review of its usage during this conflict, with reflections on further developments after 1945. This form of construction found little use subsequently, being displaced by other geosynthetic developments, but could still have a role in developing countries. Ground Improvement Volume 168 Issue GI2 The use of prefabricated bituminous surfacing geosynthetic in World War II and beyond Craig, Gallagher and Wang
Proceedings of the Institution of Civil Engineers - Geotechnical Engineering, 1998
j Outline results are presented from a single experiment in which a 1:100 linear scale model of a... more j Outline results are presented from a single experiment in which a 1:100 linear scale model of a spud-can foundation was loaded on a strati®ed foundation alongside a group of tubular piles. The loading sequence simulated initial landing, static preload proof testing consistent with the usual offshore philosophy for accommodating anticipated in-service cyclic load combinations, through to ®nal removal, of an offshore jackup rig alongside an existing structure.
The adsorption process is largely a surface-action phenomenon. In this study, sorption capacities... more The adsorption process is largely a surface-action phenomenon. In this study, sorption capacities for heavy metals on a solid waste matrix were investigated. Five heavy metals (iron, copper, zinc, nickel and cadmium) were chosen because of their availability in any landfill site. The conditions during all the experimental runs were pH 7.0, temperature 32 • C and suppressed microbial degradation. For adsorption isotherm (Freundlich and Langmuir) calculations, fixed quantities of heavy metal ions were mixed with variable quantities of solid waste. The ratio of mass of adsorbate per unit mass of adsorbent was changed five times, by changing only the adsorbent amount. The results showed that the time required to reach equilibrium varied from metal to metal but all reached equilibrium within the first 32 h. The relative potential of sorption of the individual metals and mixed metals on the solid waste matrix is Fe > Zn > Cu > Ni > Cd. The sorption capacity of domestic solid waste matrix for heavy metals is quite significant and this property might prove helpful for the in situ removal of heavy metals in landfill operation.
International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 1990
Winkler soil model was also carried out. Analytical results for pile strain distribution and surf... more Winkler soil model was also carried out. Analytical results for pile strain distribution and surface displacements compared reasonably well with measured values. 906357 Analysis of pile groups with variable shnft-ioad over point-load ratios. Technical note Ciemente, J L M
A critical review is presented which draws together results from model tests and computations on ... more A critical review is presented which draws together results from model tests and computations on the mechanisms by which the spud-can foundation of an independent leg offshore jack-up structure can penetrate deeply into the seabed through both uniform and stratified deposits. Particular consideration is given to the so-called punch-through mode in layered soil profiles, where a strong stratum overlies a weaker one. Little evidence has been found to support the mechanical basis of two methods of analysis commonly used in the offshore industry where foundations often have dimensions in excess of 10 m while conventional laboratory models have rarely exceeded 100 mm. New model tests performed in a centrifuge with stresses appropriate to offshore foundations are reported and these show different mechanisms from many unit gravity models. The need for a reappraisal of the basis of analysis is established. Where large volumes of soil are displaced by spud-can preloading, offshore analysis s...
A series of centrifuge model tests, at acceleration levels of 105 g, is reported, in which loosel... more A series of centrifuge model tests, at acceleration levels of 105 g, is reported, in which loosely placed vertical sand columns and densified sand columns have been used to improve the performance of oil storage tank foundations. A simulated tank of 34 m diameter, with a flexible base, has been subjected to incremental fluid loadings typically to 160 kPa, with foundation drainage permitted. Model preparation included the installation of as many as 572 sand columns in a single foundation. Comparison is made between the experimental results and the analysis of Priebe, which indicates that that analysis will overestimate the improvements if three-dimensional considerations are not taken into account. Comments are also included as to the extent to which model column formation may be deficient.
Uploads
Papers by William Craig