Schofield Centrifuge Centre
Environmental Geotechnics Laboratory
Environmental Ground Engineering
Soil Characterisation and Element Testing
Numerical Analysis of Porous and Granular Media
Numerical Analysis of Soil-Foundation Interaction
Field Studies - Earthquake Engineering
Dr M.D. Bolton
Dr S.P.G. Madabhushi
Professor A.N. Schofield
The Geotechnical Centrifuge Centre was renamed `The Schofield Centrifuge Centre' in September 1998 to mark the retirement of Professor A. N. Schofield. The Centre continued to provide teaching for M.Eng students, and 14 students used the mini-drum centrifuge facility to study problems of foundations on soft clay. The Centre hosted Professor T. Kimura and Professor A. J. Valsangkar during their sabbatical visits.
Industry-sponsored work has continued in relation to a wide range of topics. Work on submarine pipelines has included pipe uplift resistance in sand and clays. Research has been carried out on tunnelling, including the influence of grouting on tunnel lining deformations, the driving of piles and on embankment stability.
Work has continued on the up-grade of facilities on the balanced beam, the 2m drum and the mini-drum centrifuges.
Professor A.N. Schofield
Development of the 800mm drum centrifuge continued. Drum centrifuge development led to grant of a US patent(G24).
At the opening of the academic year Professor Schofield was invited to contribute a lecture and paper(G26)on the "Mohr Coulomb error" to Professor Pierre Habib's Jubilé Scientifique in the Senat in Paris. An Oxford Seminar on the same topic was given in June 1998. A paper on this subject was published in Ground Engineering(G27).
The opening keynote speech at the Centrifuge 98 conference in Tokyo was given by Professor Schofield(G25). New Japanese centrifuge facilities have been recently inaugurated using the drum centrifuge technology pioneered at Cambridge.
Dr S.P.G. Madabhushi
Research in soil dynamics and earthquake engineering continues with the ongoing development of new earthquake actuators. The Stored Angular Momentum (SAM) earthquake actuator was modified to accommodate a self-contained swinging platform. The SAM actuator is now one the most powerful earthquake actuators anywhere in the world(G18). Also, these developments mean that dynamic centrifuge experiments
with earthquake loading can now be carried out with a quick turn-around time on the beam centrifuge. These developments were funded by an ongoing EPSRC research grant. Research is underway to further develop the Equivalent Shear Beam (ESB) model container which simulates the semi-infinite extent of a soil layer in the field(G17) and to establish the stress-state of the soil in the ESB container prior to and after earthquake loading is applied. Use of wavelet analysis techniques has been identified as the key feature in future analysis of the data obtained in dynamic centrifuge tests.
The SAM actuator was also used to study various boundary-value problems, including the seismic behaviour of gravel embankments(G21), and liquefaction resistance of bridge foundations. This work was partially supported by Mott MacDonald, UK and is expected to lead to an EPSRC grant application in near future. Work on liquefaction-induced lateral spreading, which is partially supported by Shimizu Corporation, Japan, is underway. Also the SAM actuator is currently being used to establish the seismic behaviour of waste containment facilities. This work is being carried out in collaboration with Santa Clara University, USA. The use of the Electro Magnetic Mini Earthquake (EMME) actuator in MEng projects continues. The EMME actuator can subject small payloads to strong earthquakes of desired spectral content. The seismic behaviour of rock-fill embankments and the response of tower structures founded on liquefiable deposits during earthquake loading were the main themes of these projects.
Future research needs in soil dynamics and soil structure interactions were identified and mechanisms for interaction with industry in these areas were established(G15).
Dr R.J. Lynch
Dr M.D. Bolton
Dr K. Soga
The EU-funded programme NECER (Network of European Centrifuges for Environmental Geotechnics Research) has been an important part of this year's work, involving the development of sensor technology, studies of the kinetics of contaminants in soils, and the coordination of one of the working groups of the programme. Presentations have been made at NECER review meetings in Bochum, Delft, and Lisbon. Presentations have been made at Centrifuge 98 in Tokyo(G11), at a NICOLE (European Contaminanted Land Network) meeting in Rome, and at the SUSTECH meeting in Brussels.
Dr R Lynch
Dr M D Bolton
Dr K Soga
The development of fibre-optic photometric sensors for tracking the movement of contaminants in centrifuge experiments has continued with a new design(G30) which eliminates the g effect, experienced previously. We have shared the technology with Lisbon National Civil Engineering Laboratory, with whom we are collaborating on a joint project under the NECER programme. One of our recent PhD graduates, H. Barker, spent 6 months in Lisbon helping to design and construct their centrifuge experiment. Our Electronics Development group has been successful in improving the photometric electronics performance, to give reduced drift and improved repeatability. A centrifuge model of a landfill liner clay barrier has been built and will be tested soon.
Dr K. Soga
The study on the migration of non-aqueous phase liquid (NAPL) in soils continues. The effect of soil heterogeneity on NAPL migration/entrapment in unsaturated soils was examined using a new large 2D soil tank built with support from EC and Kajima Corporation. A new infrared digital camera was provided by ESSO to monitor the movement of NAPL and estimate the NAPL content nondestructively using the image analysis system developed by T. Ablett, the senior technician of the Geotechnical Laboratory. Hydrophobic and hydrophilic tensiometers were developed to measure the dynamic changes of liquid pressures during experiments(G11). NAPL migration in inclined soil layers was investigated by a series of centrifuge and 1g tests. The influence of slope angle of the interface between two soil layers was examined.
The study on frequency-dependent dielectric properties of clay soils also continues with potential application for a method of quick contaminant detection and remediation evaluation, in collaboration with Nishimatsu Construction. The dielectric properties from the kHz up to GHz range were measured by three different dielectric probes, which are connected to impedance and network analysers. The probes were mounted in a consolidation cell so that the changes in dielectric properties with applied stress can be examined. The developed cell was tested for its suitability to make dielectric measurements in clays contaminated with pore fluids of different chemistry(G8,G9).
Dr R.J. Lynch
Dr A. Al-Tabbaa
A new type of soil probe has been developed, which is intended to help locate non-aqueous phase pollutants
(NAPL) in the site investigation of contaminated land. The principle of this probe is based on the different refractive indices of water and hydrocarbons, and initial tests are encouraging.
Dr R J Lynch
An initial project has shown that it is possible to divert and control the direction of water-borne contaminant plumes using air sparging to create low-permeability regions. It is hoped that this technology could be used as a first line of defence in the event of a hazardous spillage. The fourth-year student who undertook this project, S. Catney, was shortlisted for The New Civil Engineer National Graduate of the Year Award.
Dr R.J. Lynch
Professor A.N. Schofield
Dr J. McKinley
Earlier work on the movement of two contaminants through a landfill liner has been published(G20). This simulation was done in a clay layer made in the mini-drum centrifuge. The different movement of an organic dye and an inorganic pollutant was observed clearly, showing retention of the organic dye but deep penetration of the inorganic contaminant was evident.
A short collaboration project with Wageningen University, The Netherlands, was completed, in which the retention of various contaminants in fine sand and silt were measured using a high pressure system. It is hoped that this will provide a rapid means of predicting contaminant breakthrough in the field.
Dr R.J. Lynch
A project to assess the benefits of a portable gas chromatograph for contaminated-land site investigation has started. This is a joint collaboration with Chemex International, a local geotechnical analytical company.
Dr S P G Madabhushi
Research in Numerical Modelling of ground water flow continues. Parallelisation of a modular FE code called MODFLOW developed by USGS was carried out and applied to simple three dimensional boundary-value problems. The performance of the parallel version of the code was compared with that of the sequential version(G16).
Dr A. Al-Tabbaa
A research and development contract funded by the Department of the Environment and carried out in collaboration with industry was successfully completed. The work involved the development and application of an in situ treatment methodology on a contaminated site using physical and chemical immobilisation of the contaminants using a soil-mixing technique with a specially developed auger. Details and results of the research work have appeared in the Proceedings of the ICE(G3,G4). Work has continued since the completion of the project, testing the cored site samples over a 28 month-period; and the results have been submitted to the ICE for publication. Related work on the long-term permeability and durability of solidified contaminated sand has been published(G5). Work on the application of soil mixing to in-situ bioremediation using biofilm technology in order to combine immobilisation with eventual treatment is ongoing(G7). A three-year PhD project on contaminant transport and in-situ immobilisation using soil mixing in stratified sand has just been completed. More recent work has been investigating the effectiveness of overlapping zones of soil-mixed columns and soil mixing of dry additives. A current MPhil project is investigating the effectiveness of various materials, such as activated carbon, shredded tyre and compost, as part of an active barrier system.
Work on the re-use of waste materials in soil-waste mixtures for geotechnical and geo-environmental applications such as light-weight fill materials and landfill liners continues, concentrating on shredded tyre and waste compost(G1,G6).
Dr K. Soga
There has been progress on the accurate measurement of stiffness of soils in a triaxial cell. Using a pulse-transmission method, the S wave velocity of London Clay was measured at various stress conditions to investigate the effect of fabric anisotropy. A theoretical micromechanics model, which includes the effect of fabric anisotropy, was developed, and the model was compared to the test results. A new cantilever-type Linear Displacement Transducer (LDT) was developed by S. Chandler, the chief technician of the Geotechnical Laboratory, to measure the axial strain of a triaxial sample very accurately (to the order of 10-5 strain). In conjunction with accurate radial strain measurement, using proximity transducers, the new triaxial system is now capable of measuring the stiffness of soils even at very small strain levels. Development of a new hollow cylinder torsional shear device has been commenced.
Work continues on the study of cyclic behaviour of sands. The effect of pore fluid viscosity on damping and liquefaction behaviour in sand was investigated using data from resonant column tests, in collaboration with Shimizu Corporation, Japan. The results indicate that the relative significance of viscous damping increases with pore fluid viscosity and loading frequency, but reduces with increasing sand particle size and strain amplitude(G10).
A new three-year EPSRC project "Investigation of time effects on soil behaviour and their influence on construction activities" started in collaboration with Brown and Root Civil, Cambridge Insitu and Geotechnical Consulting Group. The primary objectives of the research are (i) to gain a better understanding of the mechanisms of rate-effect, creep and ageing of soils in relation to soil structure, and (ii) to examine the effects of time-dependent soil properties on construction activities of geotechnical structures. At the present, complex interactions between consolidation, creep and ageing of soils are still not well understood. In particular, uncertainty remains as to whether the mechanisms for the observed increase in apparent preconsolidation pressure, strength and stiffness with time are chemical, physical, or both. The research will investigate these fundamental problems in relation to construction activities.
Dr M.D. Bolton
Dr G.R. McDowell
Work continues in the area of clastic mechanics, which refers to the quasi-continuum deformation of an aggregate of elastic but brittle grains which may, fracture and slide. A statistical description of the successive fracturing of particles shows promise for the understanding of self-similarity in a wide range of materials from tectonic mélanges to sedimented clays.
Two influences on grain crushing are essential. Smallness of grains leads to some relative strengthening: small brittle components are always stronger on a Griffith analysis of fracture since the flaws within them must be smaller. But smallness of grains leads to relative vulnerability since the smallest grains have the fewest contacting neighbours (smallest co-ordination number) and the tensile stresses induced inside particles are strongly reduced if a particle is well-supported by many neighbours. For a given macroscopic compressive stress, it emerges that the coordination effect of reduced tensile stress outweighs the Griffith effect of increased fracture strength. The smallest particles are the ones which tend to break. Griffith simply provides for some hardening as the broken fragments themselves continue to break, generation by generation. Novel algorithms have been developed for the efficient tracking of fragments, and the computation of particle-size-distributions. The effects of the dispersion of particle sizes, due to crushing, can inform other facets of soil behaviour. Void filling should obviously link with changes in the soil's hydraulic conductivity. Disparity of particle sizes following crushing has also been shown to relate to the strong hysteresis observed in unloading and reloading tests on soils. The contrast in stiffness between relatively large inclusions comprising original grains, and the fractal matrix which comes to surround them, leads to progressive slippage of the smaller grains.
Dr K. Soga
A finite-element program, which simulates the coupled consolidation and contaminant transport problem, has been developed. The program has small-strain and finite-deformation options. A finite-deformation Cam-clay model was developed to model the behaviour of slurry clays, and it was implemented into the program to analyse the deformation of mineral wastes disposed of in containment ponds or impoundments.
Numerical modelling of pipeline-soil interaction continues with support from Tokyo Gas, as part of International Collaborative Soil/Pipe Interaction Research. Advanced soil models (bounding surface model and NorSand model) have been implemented into a finite-element program to estimate soil pressures applied to pipelines by lateral movements of soils due to landslides and earthquake.
Numerical modelling of compensation grouting has been conducted. Cavity-expansion type grouting was modelled and the effect of soil consolidation caused by the excess pore pressure generation during grout injection was investigated at various soil conditions. A simple compensation grouting model has been developed using the grout efficiency factor obtained from the numerical analysis. This model will be implemented in FLAC3D by Tractabel (Belgium) as part of the COSMUS project (see below). Modelling of hydrofracturing type-grouting has also begun.
Dr S.P.G. Madabhushi
Numerical analyses are currently being carried out on the response of gravity quay walls with dry and saturated backfills during earthquake loading. Efforts are underway to compare the numerical predictions of the response of gravity quay walls with those obtained for flexible quay walls.
Dr A. Al-Tabbaa
Numerical analyses, in parallel with experimental work, are being carried out on the problem of the design of piled foundations in consolidating and swelling clays in order to minimise the use of reinforcement, and hence costs. The analyses incorporate the use of a realistic soil model which predicts the behaviour of clay in overconsolidated stress states by modelling it as an elasto-plastic material rather than a purely elastic material, which is the common practice. Three-dimensional analyses have been initiated and are being compared with axisymmetric analyses. Experimental work is being carried out in the centrifuge using an instrumented pile. The change in the weight of the soil at different gravities is being used to cause downdrag and uplift of the soil. Forthcoming tests will model end-bearing and floating piles for the cases of a single pile and a pile group.
Dr S.P.G. Madabhushi
Collaboration with the Princess Margaret Rose Orthopaedic hospital in Edinburgh continues. As a part of this collaboration a new shear-testing (CAM-Shear) apparatus has been developed specifically to establish the constitutive behaviour of bone graft. This apparatus is currently being used to test both the natural (sterilised) bone graft as well as artificial materials currently being developed in the pharmaceutical industry. Research is currently being planned to study the stability of bone graft in both revision Total Hip Arthoplasties and Acetabulum repairs. Research into determining the mean pore size of the compacted bone graft is underway(G14).
Dr M.D. Bolton
Collaboration continues with the Department of Neurosurgery and the Addenbrookes Hospital Brain Imaging Unit. Numerical simulations are underway of a variety of brain deformations arising from hydrocephalus, tumour growth and associated surgery, stroke, and contusion(G22).
Dr K. Soga
A report has been produced of the field investigation of soil liquefaction effects observed in the Kobe earthquake of 1995(G29).
Dr K. Soga
Dr M.D Bolton
Professor R.J. Mair
Work continues on the EC funded COSMUS project, in collaboration with Soletanche-Bachy, Tractabel, Glotzl, CEA-LETI and EPFL. The project aims at developing a tunnel construction system using improved monitoring techniques, a soil-characterisation system and an advanced computer-simulation model. The contributions from Cambridge are (i) to develop methods to help characterise in-situ soil conditions from drilling parameters and (ii) to model compensation grouting and tunnelling operations by the finite-element method. The standardised Soletanche-Bachy's ENPASOL drilling method has been tested at the Kennington site in London. The signal analysis of the data showed that the standardised method provides consistent data to identify the variation of soil layers in the ground. Based on extensive signal analysis of the data, a new method of eliminating the noise from the EPNPASOL signals has been proposed. Work continues to develop new drilling parameters for soils and to correlate them to soil properties.
A new finite-element program, which simulates the advancement and excavation processes of shield tunnelling operations, has been developed in collaboration with Dr K. Komiya of Chiba Institute of Technology as part of a COSMUS project. In this program, a new excavating finite element, which models the disturbed soil in front of the cutting face, is introduced, and the operation of shield advancement and of soil excavation is simulated by using the finite- element remeshing technique at each time step of the analysis.
A study of the effects of compensation grouting on tunnel linings has started with support from Nishimatsu Construction. Field monitoring was performed at the Docklands Extension Tunnel construction site, in London. Measurements of surface settlements and displacements of the tunnel lining were made during the construction of the tunnel. Centrifuge modelling of the problem has been undertaken and the influences of width of the grouted zone and its distance above the tunnel have been explored.
A new two-year EPSRC project "Investigation of ground loading applied to an old London Underground Ltd (LUL) tunnel" commenced in conjunction with London Underground and Geotechnical Consulting Group. The aim of the project is to assess the long-term ground-loading acting on tunnel linings in London Clay. A tunnel, which is part of the Kennington Loop on the Northern Line, was identified as being suitable for detailed field measurements. In order to determine the in-situ soil parameters, a series of self-boring expansion pressuremeter tests, self-boring load-cell pressuremeter tests and self-boring permeameter tests was performed. Other ground investigation included rotary-cored sampling for advanced soil testing and the installation of vibrating-wire piezometers from the ground surface and from inside the tunnel. The information obtained is to be used to interpret the long-term behaviour of the ground and of the tunnel lining and to assess the implications for current tunnel design methods.
G1. Al-Tabbaa, A., Aravinthan, T. Engineered clay-shredded tyre mixtures as barrier materials. Proceedings, International Containment Technology Conference and Exhibition, St Petersburg, FL, USA, 621-627 (February 1997).
G2. Al-Tabbaa, A., Aravinthan, T. Natural clay shredded tire mixtures as landfill barrier materials. Waste Management, 18, (1), 9-16 (1998).
G3. Al-Tabbaa, A., Evans, C.W. Pilot in situ auger mixing treatment of a contaminated site. Part 1: treatability study. Proceedings of the Institution of Civil Engineers, Geotechnical Engineering, 131, (1), 52-59 (January 1998).
G4. Al-Tabbaa, A., Evans, C.W., Wallace, C.J. Pilot in situ auger mixing treatment of a contaminated site. Part 2: Site trial. Proceedings of the Institution of Civil Engineers, Geotechnical Engineering, 131, (2), 89-95 (April 1998).
G5. Al-Tabbaa, A., King, S.D. Time effects of three contaminants on the durability and permeability of a solidified sand. Environmental Technology, 19, (4), 410-407 (1998).
G6. Al-Tabbaa, A., Nicholson, E.J. Geotechnical applications for engineered soil-waste compost mixtures. Environmental Geotechnics: Proceedings, 3rd International Congress, Lisbon, Portugal (September 1998); Edited by P.S. Sêco e Pinto, 2, 609-914 (Balkema, Rotterdam, 1998). ISBN 90 5809 006 X
G7. Brough, M.J., Martin, R.J., Al-Tabbaa, A. In situ subsurface active biofilm barriers. Ground Engineering, 31, (3), 32 (March 1998).
G8. Carrier, M., Soga, K. Dielectric measurements of clay as a potential method of contaminant detection. Environmental Geotechnics: Proceedings, 3rd International Congress, Lisbon, Portugal (September 1998); Edited by P.S. Sêco e Pinto, 2, 491-496 (Balkema, Rotterdam, 1998). ISBN 90 5809 006 X
G9. Carrier, M., Soga, K. Dielectric measurements of clay as a potential method of contaminant detection. Proceedings, 6th International FZK/TNO Conference on Contaminated Soil, ConSoil 98, Edinburgh (May 1998), 2, 807-808 (Thomas Telford, 1998). ISBN 0 72 772675 7
G10. Ellis, E.A., Soga, K., Bransby, M.F., Sato, M. Effect of pore fluid viscosity on the cyclic behaviour of sands. Centrifuge 98: Proceedings, International Conference on Centrifuge, Tokyo, Japan (September 1998); Edited by T.Kimura, O. Kusakabe, J. Takemura, 1, 217-222 (Balkema, Rotterdam, 1998).
G11. Garnier, J., Thorel, L., Lynch, R., Bolton, M., Kechavarzi, C., Treadaway, A., Coumoulos, H., Soga, K., Konig, D., Rezzoug, A., Heibrock, G.,Weststrate, F., van der Poel, J., Oung, O., Shrijver, R., Taylor, R., Robson, S., Spiessl, S., Allersma, H., Esposito, G., Davies, M., Burkhart,S., Merrifield, C., Craig, W. NECER Network of European Centrifuges for Enviromentally Geotechnic Research. Centrifuge 98: Proceedings, International Conference on Centrifuge, Tokyo, Japan (September 1998); Edited by T. Kimura, O. Kusakabe, J. Takemura, 2, 33-55 (Balkema, Rotterdam, 1998).
G12. Gui, M.W., Bolton, M.D. Geometry and scale effects in CPT and pile design. Geotechnical Site Characterization: 1st International Conference on Site Characterization, ISC 98, Atlanta, GA, USA (April 1998); Edited by P.K. Robertson, P.W. Mayne, 1063-1068 (Balkema, Brookfield, VT, USA, 1998). ISBN 9-05-410939-4
G13. Gui, M.W., Bolton, M.D., GARNIER, J., CORTE, J.F., BagGe, G., Laue, J., Renzi, R. Guidelines for cone penetration tests in sand. Centrifuge 98: Proceedings, International Conference on Centrifuge, Tokyo, Japan (September 1998); Edited by T. Kimura, O. Kusakabe, J. Takemura, 1, 155-160 (Balkema, Rotterdam, 1998). ISBN 9-05-410987-4
G14. Howie, C.R., Gillespie, W.J., Brewster, N.A., Madabhushi, S.P.G., Usmani, A.S., Fairbairn, D.R. Achieving optimal stability in impaction grafting. Proceedings, 10th Combined Meeting of the Orthapaedic Associations of English Speaking World, Auckland, New Zealand (March 1998).
G15. Madabhushi, S.P.G. Mechanisms for industry/academic interactions. Proceedings, Society for Earthquake and Civil Engineering Dynamics Workshop on Research Needs in Earthquake Engineering, London (April 1998).
G16. Madabhushi, S.P.G., Belloti, D., Clematis, A., Fernandes, P. Parallelisation of a finite difference code for modelling ground water flow. Proceedings, 12th International Conference on Computational Methods in Water Resources, CMWR XII '98, Crete, Greece, 1, 372-378 (June 1998).
G17. Madabhushi, S.P.G., Butler, G., Schofield, A.N. Design of an equivalent shear beam (ESB) model container for use on the large US army waterways experiment station centrifuge. Centrifuge 98: Proceedings, International Conference on Centrifuge, Tokyo, Japan (September 1998); Edited by T. Kimura, O. Kusakabe, J. Takemura, 1, 117-122 (Balkema, Rotterdam, 1998).
G18. Madabhushi, S.P.G., Schofield, A.N., Lesley, S. A new stored angular momentum (SAM) based earthquake actuator. Centrifuge 98: Proceedings, International Conference on Centrifuge, Tokyo, Japan (September 1998); Edited by T. Kimura, O. Kusakabe, J. Takemura, 1, 111-116 (Balkema, Rotterdam, 1998).
G19. Madabhushi, S.P.G., Zeng, X. Seismic response of gravity quay walls. II: Numerical modeling. Journal of Geotechnical and Geoenvironmental Engineering (ASCE), 124, (5), 418-427 (May 1998).
G20. McKinley, J.D., Price, B.A., Lynch, R.J., Schofield, A.N. Centrifuge modelling the transport of a pulse of two contaminants through a clay layer. Geotechnique, 48, (3), 421-425 (1998).
G21. Peiris, L.M.N., Madabushi, S.P.G., Schofield, A.N. Behaviour of gravel embankments founded on loose saturated sand deposits subjected to earthquakes and with different pore fluids. Centrifuge 98: Proceedings, International Conference on Centrifuge, Tokyo, Japan (September 1998); Edited by T. Kimura, O. Kusakabe, J.Takemura, 1, 263-270 (Balkema, Rotterdam, 1998).
G22. Pena, A., Bolton, M.D., Pickard, J.D. Cellular poroelasticity: a theoretical model for soft tissue mechanics. Poromechanics: a Tribute to Maurice A. Biot: Proceedings, Biot Conference on Poromechanics, Louvain-la-Neuve, Belgium (September 1998); Edited by J.F. Thimus, and others, 475-480 (Balkema, Brookfield, VT, USA, 1998). ISBN 90 5 809003 5
G23. Robertson, D., Bolton, M.D., McDowell, G.R. Numerical representation of fracturing granular materials. International Journal for Numerical and Analytical Methods in Geomechanics, 21, (12), 825-843 (December 1997).
G24. Schofield, A.N. Centrifuges and associated apparatus and methods. United States Patent 5,634,876 (June 1997).
G25. Schofield, A.N. Geotechnical centrifuge development can correct soil mechanics errors. Centrifuge 98: Proceedings, International Conference on Centrifuge, Tokyo, Japan (September 1998); Edited by T. Kimura, O. Kusakabe, J.Takemura (Balkema, Rotterdam, 1998).
G26. Schofield, A.N. The Mohr Coulomb error. Colloque Mécanique et Géotechnique, Jubilé Scientifique de Pierre Habib, Paris, France (May 1998); Edited by Luoung, 19-27 (LMS Ecole Polytechnique, 1998).
G27. Schofield, A.N. Mohr Coulomb error correction. Ground Engineering, 31, (8), 30-32 (August 1998).
G28. Springman, S.M., Schofield, A.N. Monotonic lateral load transfer from a jack-up platform lattice leg to a soft clay deposit. Centrifuge 98: Proceedings, International Conference on Centrifuge, Tokyo, Japan (September 1998); Edited by T. Kimura, O. Kusakabe, J. Takemura, 1, 563-568 (Balkema, Rotterdam, 1998). ISBN 9-05-410987-4
G29. Soga, K. Soil liquefaction effects observed in the Kobe earthquake of 1995. Proceedings of the Institution of Civil Engineers, Geotechnical Engineering, 131, (1), 34-51 (January 1998).
G30. Treadaway, A.C.J., Lynch, R.J., Bolton, M.D., Barker, H. Pollutant tracking with in-situ fibre-optic photometric sensors in a geotechnical centrifuge. Environmental Geotechnics: Proceedings, 3rd International Congress, Lisbon, Portugal (September 1998); Edited by P.S. Sêco e Pinto, 2, 441-447 (Balkema, Rotterdam, 1998). ISBN 90 5809 006 X
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Last modified: October 1999