bluuebunny/crossref_metadata_2025 huggingface dataset:
Waste disposal in steep-sided quarries: geomembrane-based barrier systems
Authors: Jones D. R. V.
Published: April 2008

The use of geomembrane liners on landfill sites in the UK has been widespread since the mid-1980s. Various types and thicknesses exist although high-density polyethylene (HDPE) liners are the most widely used for basal and side lining. Planning authorities still regard the import of waste materials as one of the best means of restoring worked mineral voids. The waste disposal industry must therefore continue to develop old quarry sites in order to provide a reasonable land bank of refuse disposal sites for the community. The engineering of these sites has become increasingly more difficult as the requirements for lining have tightened due to the need to contain leachate and landfill gas. This paper discusses the use of geomembrane liners for landfill applications, with particular reference to steep sided-quarries.
Ground investigation and design for a landfill at Seater, Caithness
Authors: Croxford A. J.
Published: April 2008

This paper describes the site investigations and design considerations for a landfill development near Wick in Caithness, Scotland. The site is underlain by the Caithness Flagstone Series of the Middle Devonian with a thin cover of boulder clay and peaty topsoils. The location is on raised ground sloping gently to the north with poor natural drainage. The near-surface geology was investigated with a combination of ground-probing radar and trial pitting. Radar profiles from traverses across the site were correlated with the lithological information from the trial pits to provide an estimate of the thickness and nature of the superficial deposits. Groundwater and surface water conditions were investigated and a water balance calculated for design considerations. The final design allows for a 25-year landfilling facility operated on the containment principle. Perimeter, sub-level and internal drainage systems were incorporated in the design.
Stability considerations in landfill lining design
Authors: Dixon J. H. , Bentley S. P.
Published: April 2008

Modern landfills are generally designed with a composite base and side lining system consisting of a low-permeability mineral layer overlain by a geomembrane. Methods of installation, quality assurance procedures and chemical compatibility are well addressed in most contract specifications. However, fundamental stability considerations including the control of tensile strain are often overlooked in the design. These factors may be critical to the performance of the lining system. This paper examines designs using structural geogrids to avoid stability problems associated with the lining system.
Application of induced seismicity to radioactive waste management programmes
Authors: Young R. Paul
Published: April 2008

Induced seismicity can make a unique contribution to our understanding of rock mass response due to excavation and thermal-induced loads, during the site characterization and performance monitoring of a nuclear waste repository. Field data, with supplementary laboratory studies, are presented to show how induced high-frequency acoustic emission/microseismicity (AE/MS) can be used as a tool for passive volumetric remote sensing of failure processes. Case studies are described using results
from experiments carried out at Atomic Energy of Canada Ltd's (AECL) Underground Research Laboratory (URL). This site has been operated for the last ten years to investigate the concept of safe disposal of nuclear waste fuel in a granitic rock mass at 420 m depth.
Storage of hazardous waste at shallow depths
Authors: Christiansson R. , Jernlås R.
Published: April 2008

The possibilities of depositing environmentally hazardous waste in crystalline rock are evaluated for the special case where the waste is placed above the groundwater table. Layouts are proposed together with the siting process and costs. The environmental aspects are discussed for three types of waste. It is concluded that storage of hazardous waste could be done with good long time stability at many locations in Sweden. However, depending on the amount of dilution, some wastes might need
improvements.
Factors affecting the containment properties of natural clays
Authors: Arch Jonathan , Stevenson Emma , Maltman Alex
Published: April 2008

Natural clays are often relied upon to provide containment for the safe disposal of wastes, either as an
in situ
material or as an engineered fill material. It is generally assumed that these materials will permanently exhibit a low permeability, and that they are isotropic and homogeneous. However, anisotropies and discontinuities are often present in clays, or may be induced by deformation which can occur during or after construction of waste disposal sites. Anisotropic fabrics may also be developed or enhanced within clays as they are compacted and consolidated. Many landfill sites are dynamic environments where deformation will occur both within the waste and in the material surrounding the waste. When clays deform, for example due to slope instability or differential settlement, the deformation will generally be accommodated by the development of discrete microscopic shear zones which have the potential to significantly change the containment ability of clays. This paper presents the results of a study to investigate the variation in the permeability of clays as a result of their deformation. Natural examples, theoretical studies and experimental data are combined to demonstrate that fluids will preferentially flow along shear zones or induced fabrics. The data are used to demonstrate that, in a dynamic environment such as a waste disposal site, the permeability of clays can increase substantially in materials which become heavily deformed.
The containment properties of glacial tills: a case study from Hardwick Airfield, Norfolk
Authors: Gray J. M.
Published: April 2008

Although of relatively low permeability, glacial tills may have deficiencies that make them less suitable as natural leachate containment materials. These deficiencies include sand lenses, fissures, and weathering zones. Geotechnical investigations of proposed unlined containment sites on tills must fully assess the impact of these and other deficiencies. This paper examines the proposals for a household and commercial waste containment site on Lowestoft Till at Hardwick Airfield, Norfolk, and concludes that the site deficiencies had not been adequately investigated or recognized. This led to difficulties for the consultants at a public inquiry into the proposals.
Suction-controlled oedometer tests in montmorillonite clay: preliminary results
Authors: Villar M. V. , Martin P. L.
Published: April 2008

A Spanish montmorillonite clay is being characterized in its unsaturated state for use as a sealing material in high-level radioactive waste repositories. The ‘water content versus suction’ curve has been determined and oedometer tests are being performed under suction pressures, ranging from 0.1 to 100 MPa, controlled by air pressure or sulphuric acid solutions. The methodology of the tests is described and the first results are presented.
Resistivity (Ω-method) method for environmental monitoring: a new approach
Authors: Narayan Satyendra , Dusseault M. B.
Published: April 2008

A large number of landfills and waste disposal sites have been located on or in alluvial and glacial deposits. Fine- grained silts and clay layers in these alluvial deposits, or man-made liners of rolled clay, perhaps combined with a polymer sheeting, are important barriers and retardants to vertical leachate migration underneath the landfills. Ideally, these barriers prevent leachates from contaminating groundwater, and resistivity surveys are useful to study site integrity, provided a sufficient resistivity contrast exists. In this article, we introduce a different approach for resistivity monitoring of landfills, waste fluid ponds, salt storage sites, or other sites where environmental concerns exist as to the migration of materials through porous or fractured media. The method is based on the measurement of the horizontal gradient of the vertical electric field as a function of receiver distance. Numerical model responses over a hypothetical landfill model are presented to demonstrate the method. Model results show that monitoring the vertical electric field and presenting the horizontal gradient of the vertical electric field as a function of sampling distance provides good sensitivity to track the movement of an anomalous resistivity zone. The theory is complete, but the method needs to be field tested to determine operational sensitivity and repeatability.
The geotechnical value of ground stiffness determined using seismic methods
Authors: Matthews M. C. , Hope V. S. , Clayton C. R. I.
Published: April 2008

Geotechnical design routinely requires that the
in situ
strength, stiffness and permeability of the ground be determined. Most satisfactory designs for constructions such as buildings, excavations and tunnels ensure that an adequate margin of safety is maintained, and, under these conditions, measurements of the stiffness of the ground are required so that movements in the ground, both during and after construction, can be calculated.

Over the past two decades the careful back-analysis of the behaviour of the ground around constructions such as tunnels and excavations has repeatedly shown that the
in situ
stiffness of soils and rocks is much higher than was previously thought, and that stress—strain behaviour of these materials is non-linear in most cases. Numerical analyses, using finite element and finite difference computations and field observations, have demonstrated that when margins of safety are adequate the strain levels in the ground around retaining walls, foundations and tunnels are small, and typically of the order of 0.0-l%–0.1%. Improved measurements in the laboratory have confirmed the non-linear stress-strain behaviour of soil, and shown that stiffness is much higher when measured locally and at small strain levels than when determined using conventional laboratory techniques.

The realization that strain levels around construction are small, and that field stiffnesses are much higher than previously measured in the laboratory, has led us to re-appraise the value of stiffnesses derived from field seismic geophysical methods. Such methods allow stiffnesses to be determined on representative volumes of the ground, and at the
in situ
stress state, and for this reason may provide valuable data. This paper reviews the importance of stiffness in
geotechnical design and how seismic methods are used in ground stiffness investigations.
Radar tomography applied to foundation design in a karstic environment
Authors: Corin L. , Couchard I. , Dethy B. , Halleux L. , Monjoie A. , Richter T. , Wauters J. P.
Published: April 2008

A case history illustrating an innovative application of borehole radar tomography to foundation problems in a karstic area is presented. The principles of the method and the geotechnical interpretation of the results are discussed. It is shown that, although ground conditions may be considered as very unfavourable for reflection radar techniques, good results were achieved in the crosshole mode, giving valuable information on both the geometry and the characteristics of the subsurface.
Seismic tomography survey under the La Gileppe Dam
Authors: Demanet D. , Jongmans D.
Published: April 2008

A tomographic survey of 15 panels was performed under the La Gileppe dam (Belgium) to assess the degree of fracturing in the rock foundation which consists of steeply dipping beds of sandstone and shale. A particular aim of the study was to locate fracture zones likely to cause leakage under the dam. The panel dimensions range from 9 by 15 m (between 2 boreholes) to 60 by 40 m (between 4 boreholes). An explosive source and a 12 hydrophone string were used for the experiment. The data inversion was made with the Rai2D software of the L.C.P.C. (Laboratoire Central des Ponts et ChaussÉes), based on the SIRT algorithm with circular ray paths. The velocity values were influenced both by rock type and fracturing. The tomography method has been shown to image successfully low velocity fracture zones which could not have been determined by classical cross-hole tests. In some cases, tomograms showed cross shape images with a high velocity zone along the diagonals. These artefacts have been explained by numerical modelling as a result of the poor angular ray coverage of the section.
Contribution of electrical and acoustic methods in the evaluation of the condition of accessible underground pipework and its environment
Authors: Cabassut L. , Bourget M. , Frappa M. , Al Heib M. , Viguier C. , Guérin J.F.
Published: April 2008

In the maintenance of main drainage sewers it is necessary to characterize their mechanical behaviour along their length. This can be achieved by indirect geophysical methods in which ultrasonic and electrical resistivity measurements are used to locate the main zones subjected to high external stresses. Both approaches have been verified by a programme of
in situ
measurements.
Resistivity sounding: two case studies from the Cretaceous Chalk at Boxgrove, West Sussex and Barnham, Suffolk, UK
Authors: Roberts C. L. , Lewis S. G.
Published: April 2008

Resistivity sounding is successfully used to determine depth to Cretaceous Chalk bedrock at two contrasting sites. The trend of a buried cliff-line is highlighted at Boxgrove, where the ancient cliff is modelled at around 40 m O.D. with a seaward Chalk platform between 35 m and 40 m O.D.. At Barnham, the configuration of a Middle Pleistocene glacial river channel is constrained and resistivity variations in response to lithological changes noted. Solid Cretaceous Chalk reveals a resistivity value of 105 Ωm, rising to 130–142 Ωm at weathered horizons.
Downhole geophysical investigations for a proposed deep highway cutting adjacent to a rail tunnel at Murrurundi, NSW, Australia
Authors: Won G. W. , Raper R. W. J.
Published: April 2008

Downhole seismic methods have been used to characterize the rock mass for a proposed deep highway cutting adjacent to an existing rail tunnel at Murrurundi, northern NSW, Australia. Site geological conditions are complex and with a major reverse fault intersecting the cutting. Two 120 m deep boreholes adjacent to the tunnel were geophysically logged through a sequence of basalt lavas, tuffs and agglomerates. Multichannel P and S wave sonic, density and dual focussed electric logs were used. Geophysical field tests results have been correlated with laboratory static and dynamic tests on selected rock core to characterize the
in situ
rock mass properties for finite element analysis.
Seismic refraction survey in Bernburg, Germany: an application of the generalized reciprocal and phantoming methods
Authors: Horrent C. , Brouyère S. , Demanet D. , Michiels T. , Jongmans D.
Published: April 2008

The paper presents a case study of a seismic refraction survey in Bernburg, Germany. The interpretation was made using the GRM method and phantoming concept. The aim of the survey was to map the depth of the bed-rock over a distance of 2 km. The survey was divided into five linear profiles ranging from 150 to 640 metres in length. The resulting interpreted sections show substantial variations in velocity (1300 to 4500 m/s) and depth (5 to 18 m) of bed-rock. Correlation with existing boreholes shows that the top of the bed-rock is located with an accuracy of the order of 1 metre.
Engineering and environmental geophysics: the future
Authors: Annan A. P.
Published: April 2008

The field of engineering and environmental geophysics developed slowly until the last decade. The traditional use of geophysics for engineering was typically limited to refraction seismic for depth to bedrock and rippability. As technology evolved, applications expanded in a slow but steady manner.

The geophysical community has been slow in learning the requirements of the engineering community. Historically, geophysicists have often been focused on the exploration aspect with the primary emphasis on finding the pot of gold. This pot of gold may have been either oil or minerals; in both cases, a major return on investment for a successful utilization of geophysics could be realized.

In engineering and environmental geophysics, quantifying the cost benefits of using geophysical methods is much harder. Furthermore, geophysical information is difficult to convey in a format which is understandable by the civil engineer, engineering geologist, hydrogeologist or lay person (i.e. lawyer) who must use the information but is not well versed with the idiosyncrasies of geophysical methodology, data presentation and interpretation.

Over the last five years a substantial improvement in data presentation has been noticeable. In part this is due to a better understanding of the end-users’ needs and, in part, due to the availability of low-cost computer technology, which permits much more enhanced data presentation than ever before.

Investment in instrumentation and software development for the engineering and environmental geophysics field has been limited. Now, as the technologies become identified as useful, development of technology specifically for the engineering environmental market is occurring.

The engineering and environmental field is developing but must become much more professional with improved education and standards during the next decade. Price resistance to quality geophysics has been a major obstacle to advances. Recent examples of price cutting, particularly evident in North America, are undermining capacity for professional advancement and improvement in service quality. In the future, profit margins for engineering geophysical services must not be sacrificed if the value of the product is to be perceived and the cost benefits of professional engineering geophysics realized in the engineering community.
Rock engineering rating system for assessing the suitability of armourstone sources
Authors: Lienhart D. A.
Published: April 2008

The process involved in assessing and selecting a potential source of armourstone of suitable quality is one of great complexity. The process involves the inspection and evaluation of the quarry and its production methods, testing of the processed stone, evaluation of the quality of both intact and processed stone, and consideration of both the transportation methods and placement techniques. The entire process, from quarry selection to placement at the project, may be viewed as a rock engineering system. The use of a rock engineering interaction matrix simplifies an understanding of how various factors affecting the quality of quarried armourstone are interrelated. Through this understanding of the various interrelationships a weighted rock engineering rating system may be developed for the assessment of the suitability of various armourstone sources. Such a rating system is designed to pull together all the factors related to both the field and laboratory investigations of a potential source, enabling geologists at all experience levels to arrive at a well-founded conclusion concerning the potential quality of stone produced from a particular armourstone source.
Opening and operation of the Pasir Panjang quarry: a dedicated armourstone quarry in the Malaysian jungle
Authors: Van Meulen J. A.
Published: April 2008

In August 1993 Baggermaatschappij Boshalis was awarded a contract for the construction of a breakwater (1400 m parallel to the coast) and four rock groynes (180 m each) in Malaysia. The award was based on the company's alternative design, which was to use 11 and 20 t concrete armour units (tetrapods) totaling 115 000 m
3
of concrete and 2.1 x 10
6
t of rock with sizes from 50 mm to 9.0 t. The quantities of the various rock grades chosen in the alternative design were optimized to suit the assumed production possibilities of rock block sizes from sources in the area. After award of the contract, a new quarry only 8.0 km from the construction site was opened, the nearest existing quarry being 38 km away. The new quarry started deliveries on 1 April 1994 and completed them on 17 April 1995.

A case history of the quarry is presented, emphasizing the economic importance of the rock fragmentation and the logistics common to most dedicated armourstone quarry operations. It describes the tender stage, the choice of quarry location and the choice of the various specified rock gradings made during the breakwater design process. The blasting procedures used to obtain the required gradings and quantities are discussed. The particular features and problems associated with opening and operating a dedicated armourstone quarry — for example, the selection plant, the stockpiling procedures, shipping and materials quality control procedures — are amplified upon.
Abrasion of a series of tracer materials on a gravel beach, Slapton Sands, Devon, UK
Authors: Latham J.-P. , Hoad J. P. , Newton M.
Published: April 2008

While increased attention is being paid to the use of quarried rock in groynes, revetments and breakwaters, and to beach recharge, the large volumes of materials and the associated environmental costs of obtaining these resources has begun to focus minds. Interest in the possible future use of a wider range of material sizes and qualities for beach recharge and in the use of smaller armour block sizes which move during profile adjustment has been growing. Deployment of these dynamic materials for coastal protection structures has focussed research on the long-term performance of these materials and the implications for design life. This reflects a growing concern about the more intelligent use of finite material resources.

The vast range in intrinsic resistance of different rock types to laboratory mill abrasion is well reported and these results, when presented as the QMW mill abrasion resistance index, can give relative lifetimes of differing shingle types. However, field studies and/or degradation models of the type discussed in this paper are needed to convert these relative laboratory lifetimes to prototype environmental lifetimes in years so that they are appropriate for predicting the long-term changes in beach material volumes.

The author's 1991 rock degradation model, which gives an absolute prediction of weight loss rates, was proposed for armourstone placed within structures designed for static stability. It encorporates the mill abrasion test result for the rock type in question. However, it also attempts to embrace dynamically stable rock protection structures from gravel beaches up to berm breakwaters, depending on the mobility parameter. Before this laboratory and field study, no prototype data was available to check its applicability to gravel-sized material.

This paper presents the field results for pebbles consisting of three rock types. Their rates of weight loss with respect to interactions with indigenous beach materials in both laboratory and field trials are given. Whereas weight losses from flint or gneiss pebbles in a field experiment will be negligible, their long-term losses may be predicted from experiments and observations on beaches such as Slapton Sands, where pebbles of rapidly abrading rock types have been measured.
Possible problems with high PSV aggregate of the gritstone trade group
Authors: Woodside A. R. , Lyle P. , Woodward W. D. H. , Perry M. J.
Published: April 2008

This paper considers the methods of assessment of high PSV greywacke aggregate from the Longford Down Massif. It reviews current specification requirements concluding that PSV is regarded as the most important surfacing aggregate property in the UK. Using a set of data, PSV is correlated with other test properties including AIV, TFV, MSSV, AAV and MDE. Despite poor correlations, the data shows general trends between properties indicating that PSV is achieved at the expense of other test properties.
An investigation of some alternative aggregates for use in concrete
Authors: Butler A. K. , Harrisson A. M.
Published: April 2008

The use of some waste materials as aggregate for concrete has been investigated. Three specific materials were examined, china clay waste, slate waste and pulverized fuel ash. The project investigated methods of utilising alternative materials as aggregate either by low cost processing, novel mix design or by the use of admixtures.
Capillary influences on the operation and effectiveness of LNAPL interceptor trenches
Authors: Chapple Martin C. , Vittorio Louis F. , Tucker William A. , Richey Melissa G.
Published: April 2008

Interceptor trenches are commonly used to recover light non-aqueous-phase liquids (LNAPL) from the subsurface and are particularly effective in the recovery of floating hydrocarbons. Interceptor trenches function by creating a zone of high permeability within the aquifer either as an open excavation (where the formation permits) or filled with a suitable backfill (typically gravel) that retains the high permeability and effective porosity required of a collection system.

Numerous texts suggest that placement of an impermeable membrane is required on the down-gradient side of the trench to prevent captured LNAPL from exiting the trench on its downgradient side. Installation of such a liner can be difficult if not impossible under certain soil conditions. Simple calculations show that the membrane may not be necessary due to the hydraulic conditions created by installing the trench. Using these calculations in the preliminary design will result in an effective trench installation and correspondingly reduce installation and operation costs.

LNAPL has been shown to migrate primarily near the top of the capillary fringe in porous media. Since the high permeability and effective porosity of the trench backfill do not support a capillary fringe of similar magnitude, LNAPL rests essentially on the water table in the trench. The zone of capillary saturation on the downgradient side inhibits LNAPL migration from the trench into the native soil. Provided that recovery of the LNAPL is maintained and the thickness of LNAPL in the trench is less than the capillary fringe height in the native soil, the LNAPL will remain hydraulically trapped.

To demonstrate this condition, a review of some of the methods used to calculate the capillary fringe height was performed. To verify the magnitude of the calculated capillary fringe height and its effects on LNAPL retention within a trench, a simple laboratory-scale simulation was undertaken.
The legacy of contaminated land in Portsmouth: its identification and remediation within a socio-political context
Authors: Walton N. R. G. , Higgins A.
Published: April 2008

The unique situation of Portsmouth with regards to the historical development of large areas of filled and contaminated land is described together with the methodologies which have been developed over the past decade for identifying, investigating and remediating such lands. This happened under the impetus of both Portsmouth City Council's specific strategy for contaminated land and the increasing volume of environmental guidance which has recently been released prior to the introduction of copious new government legislation.

Three typical case histories are presented which show how different approaches to risk evaluation have evolved during the 1990s and demonstrate how Portsmouth has applied these evolving methodologies in a pragmatic way in an attempt to optimize environmental improvements and financial returns whilst minimizing both public and political risks.
Human health risk assessment using UK Guideline Values for contaminants in soils
Authors: Ferguson C. C. , Denner J. M.
Published: April 2008

In recent years the UK Department of the Environment has, with others, developed a framework for contaminated land risk assessment, including the derivation of new Guideline Values. These are an important component in an integrated procedure for site-specific risk assessment which combines consistency of approach with flexibility to ensure that local circumstances are taken into account.

Guideline Values are derived using the Contaminated Land Exposure Assessment model (CLEA) which calculates human exposure via ten different exposure pathways. The relative contributions of the pathways vary according to site use, and hence the Guideline Values may also vary. This is consistent with the UK Government's ‘suitable for use’ policy. Guideline Values may also vary as a function of soil pH, soil organic matter, etc., reflecting the influence of such parameters on contaminant partitioning between soil solids and soil solution. The research described here is underpinned by complementary work to choose the most appropriate toxicological criteria for each contaminant.

Where Guideline Values are exceeded, the intention is that either a further phase of risk assessment or remedial action is triggered. If the former is chosen the emphasis will be on establishing whether exposure conditions differ significantly from the generic conditions assumed in CLEA. This is expected to be more cost-effective in general than site-specific risk assessment procedures. It does, however, require that the exposure assumptions and data values used in deriving the Guideline Values are understood by the risk assessor so that the necessary comparisons with site-specific conditions can be made.
Professional training for geologists in contaminated land management
Authors: Nathanail C. P. , Nathanail J. F.
Published: April 2008

Contaminated land management comprises the identification, investigation, assessment and remediation of contaminated land. It is a multi-disciplinary, rapidly developing subject which involves input from, and communication between, a wide range of science, engineering and other professionals. Geologists have a key role to play at the investigation and assessment stages and have much to offer at the identification and remediation stages.

The undergraduate and post-graduate education of geologists provides many of the skills required, but many other skills can only be developed ‘on the job’. To ensure that early industrial experience covers a broad range of subjects, there is a need for training to be formalized.

The training needs for geologists working in contaminated land management have been evaluated and a training guide for geologists in contaminated land management has been written. Use of the guide will ensure that on the job training is comprehensive, relevant and assists trainee graduate geologists gain chartered geologist status within a reasonable timeframe.
The delineation of capture zones around small sources
Authors: Keating T. , Packman M. J. , Peacock A.
Published: April 2008

The delineation of capture zones and the subsequent designation of protection zones around groundwater sources is a key element of the Environment Agency ‘Policy and Practice for the Protection of Groundwater’. The protection principles apply to all sources, but priority in defining protection zones has been afforded hitherto to the major public supply sources. The EA recognizes the need to have available a methodology for establishing protection zones around the smaller sources, of which there are upwards of 76 000 in England and Wales, compared with some 4000 larger sources used principally for public water supply. The delineation of capture zones around the smaller sources presents a number of technical and practical problems which tend not to arise when carrying out such procedures for the larger sources. This paper reviews the methods for delineating groundwater source capture zones which are readily available; it discusses the practical issues associated with the application of these methods to the smaller sources, and presents recommendations for their use in a range of hydrogeological settings.
Groundwater contamination from a coal carbonization plant
Authors: Broholm Mette M. , Jones Ian , Torstensson Daniel , Arvin Erik
Published: April 2008

The Rexco coal carbonization plant near Mansfield in the UK East Midlands produced coke by the process known as ‘Rexco’ in the 1950s to early 1960s. In the process gas and coal-tar were also produced. The gas was cooled with water whereby ammonia and coal-tar in the gas were dissolved/condensed. Ammonia liquor and coal-tar are known to have leaked into the subsurface from cracked tanks at the site. Based on this, a large plume of ammonium and coal-tar compounds was expected to be present in the aquifer. Effluent compositions have been determined, and an extensive reconnaissance study of the groundwater contamination in the sandstone aquifer has been carried out. The coal-tar contained phenols, naphthalenes and BTEXs, and low levels of PAHs. The ammonia liquor contained very high concentrations of phenols and ammonium. Extensive contamination with ammonium has been encountered, indicating the ammonia liquor as the primary source of contamination. No significant contamination with specific organic coal-tar compounds is present today in spite of the extensive leaks of coal-tar and ammonia liquor in the past. The organic coal-tar compounds released with the ammonia liquor have likely been degraded/transformed in the saturated part of the aquifer as well as in the vadose zone.
Transport of dissolved creosote compounds through fractured clay: column and field experiments
Authors: Broholm K. , Jørgensen P. J. , Hansen A. B. , Nilsson B. , Sidle R. C. , Arvin E. , Fredericia J.
Published: April 2008

Transport of selected creosote compounds and tracers in two column experiments and a field study in fractured clayey till are presented. Twenty-five organic compounds were used in the column experiments and 12 in the field experiment. This paper focuses on three organic compounds: phenol, naphthalene and dibenzofuran. One column was biologically inactive, and the other was biologically active with denitrifying conditions in the beginning and aerobic/denitrifying conditions later on in the experiment. The infiltration water at the field site was aerobic in the beginning and anaerobic (no oxygen, very little nitrate, and some sulphate) later. The results showed very rapid transport through clayey till of the tracers and the organic compounds. Despite the rapid transport through fractures, biodegradation may be an important process in fractured media at least for the easily degradable organic compounds.
The problem of flooding in Ladysmith, Natal, South Africa
Authors: Bell F. G. , Mason T. R.
Published: April 2008

Ladysmith was founded in the mid-19th century alongside one of the meanders of the Klip River. The location was chosen for protection against native tribesmen, but in the last 110 years, Ladysmith has experienced 29 notable floods. The most recent floods occurred in February 1994, when the highest water levels in the last 71 years were recorded. An attempt to control flooding was made with the construction of the Windsor Dam in 1949. Unfortunately, the reservoir has been largely silted up so that its live storage capacity has been reduced to around 5%. The present flood walls in Ladysmith can be overtopped by a flood with a recurrence period of once every five years. This happens when channel flow exceeds 700 m
3
s
-1
.

A number of flood alleviation schemes have been discussed over the years including the construction of artificial levees and river canalization. The scheme in vogue at present would involve the construction of another dam and reservoir. Although the reservoir would offer protection to the town, to do so it would have to remain at 10% of its storage capacity in order to retain a 100 year flood. An alternative solution, which would be less expensive, would be to relocate those properties affected most by the recent floods.
A combined geotechnical/geophysical method for the prediction of liquefaction, with particular reference to the Fraser River Delta, British Columbia
Authors: Pyrah James , Davis Angela , Huws Dei
Published: April 2008

Over the past decade or so, much work has been undertaken into the development of various techniques for the measurement of seismic shear wave velocity, offshore, onshore and in the laboratory. Previous research has suggested that the shear wave velocity of an uncemented sand may be a useful index to its liquefaction potential. The research described in this paper has combined the concepts of critical/steady-state soil mechanics and the measurement of shear wave velocity in order to provide a new index of sand consolidation state, enabling the prediction of flow liquefaction in laboratory-prepared samples. Results obtained from the laboratory are then applied to the field situation, in this case, the Fraser River Delta, British Columbia, which is an example of a site currently undergoing a major earthquake stability evaluation. A preliminary analysis of the data indicates that the sediments around Roberts Bank, on the southwestern portion of the delta, are potentially liquefiable. This conclusion is confirmed by other, more conventional, investigative techniques.
The performance of some coastal engineering structures for shoreline stabilization and coastal defence in Trinidad, West Indies
Authors: Maharaj Russell J.
Published: April 2008

Coastal erosion in Trinidad has caused a loss of land and subsequent damage to many coastal engineering structures. Damage includes roadway failures, loss of agricultural land, coastal flooding and damage to property. In many areas, structural engineering measures have been implemented to prevent these from recurring. An example of erosion and structural measures used in a segment of rapidly eroding coastline along the east coast of the island is presented. The site is part of a coastal section of the largest wetland on the island, the Nariva Swamp, through which drains the largest river system, the Nariva River. Structural measures used include steel sheet piled revetment, steel-reinforced concrete retaining walls, gabion basket retaining structures, boulder splash aprons, a steel-reinforced concrete pile cluster, concrete columns and blocks and boulder riprap. All these an show signs of structural failure, and some have already collapsed. Failures include spelling and cracking of concrete; rebar corrosion; steel pile corrosion; foundation settlement under retaining walls and structures, with subsequent surfical cracking; basal foundation sediment scour and undermining; wave and fluvial induced removal of rip-rap and splash apron boulders, and seasonal burial and sedimentation of the splash apron and concrete pile cluster. Based on this study, it appears that construction-induced high energy conditions and oversight in design and construction were partly responsible for failures.
Earthquake-mail (E-mail?) for low-seismic zone earthquake hazard assessment
Authors: den Outer A. , Maurenbrecher P. M.
Published: April 2008

The Roermond earthquake of 13 April 1992 in the Netherlands, of magnitude 5.8 on the Richter scale, although claiming only one fatality through a heart-attack, caused significant damage estimated at £30–40 million. The low recurrence determined at 135 years for an earthquake of this magnitude, does not encourage the funding of research despite the large quantity of data assembled, especially in connection with surveys to assess compensation grants from the earthquake hazard fund set up by the Netherlands government.

Electronic mail (E-mail) is a tool made used both to transfer information and solicit information. An earthquake mail facility could be integrated in a Seismological Engineering Information System (SEIS). Such a facility is being set up to provide links between users and suppliers of the data and analysis methods in the SEIS. An earthquake discussion box, on E-mail, concerned with problems in earthquake engineering in low-seismicity countries in northwest Europe is a cautious preliminary initiative to provide a communication platform between researchers in seismology and earthquake engineering.
Landslides and their control in the Chinese Loess Plateau: models and case studies from Gansu Province, China
Authors: Meng Xing-min , Derbyshire Edward
Published: April 2008

Over much of the western part of the Loess Plateau of north China, aeolian silts averaging 150 m in thickness drape the mountainous pre-Pleistocene bedrock. The semi-arid climate with its violent monsoonal rainstorms, and the recurrent earthquakes associated with the continuing uplift of the adjacent Tibetan Plateau, contribute to frequent and rapid failure of the loess-mantled slopes. Losses of livelihood and life are amongst the most serious in all China. Landslides in eastern Gansu total more than 40000 and affect over 27% of the total area of the Province. Accelerating population growth and associated expansion in both industry and agriculture, especially since the 1950s, has added urgency to the need to improve control and management of the landslide hazard. Several approaches to control and prevention have evolved, tailored to failure type and stage of development. Some of these are discussed, particular attention being paid to certain successful procedures employed in the control of two large landslides in the major city of Tianshui. It is suggested that these slides provide a useful model for future landslide control and prevention strategies in similar urban agglomerations in the Chinese Loess Plateau.
Small is beautiful: investigations and remedial works for minor slope failures
Authors: Reid J. M.
Published: April 2008

Minor slope failures receive much less publicity than major failures such as the Scarborough landslide, but can cause considerable damage and inconvenience. The engineering geologist is often required to carry out investigations into the failure and decide on appropriate remedial works in a very short timescale and with a limited budget. Difficulties of access to the slipped area limit the use of conventional ground investigation methods, but specialized lightweight methods such as hand-operated shell and auger boring can be very useful. It is important to define the geological situation as soon as possible, in order to understand the nature of the failure and the processes driving it. Remedial works which are appropriate can then be designed. Two case studies are presented to illustrate the process of investigation, design and construction; the collapse of a sewer on the bank of the River Tay in Perth, and the subsidence of a minor road on a steep hillside near Lanark. A gabion wall and mattress was adopted in the first case; a bored pile retaining wall in the second.
An extension of probabilistic slope stability analysis of china clay deposits using geostatistics
Authors: Pascoe D. M. , Pine R. J. , Howe J. H.
Published: April 2008

An understanding of the reasons for the distribution of highly kaolinized zones in the St Austell granite is useful to the china clay industry because a better understanding of shear strength distribution spatially should lead to improved models and give better insight into the progressive development of failure surfaces.

A field cone penetrometer survey of a bench in a working china clay pit has been correlated with laboratory shear strengths of samples from the same slope. A 3-D block model produced using a commercial integrated mining software package was then incorporated into a slope stability analysis.

The results were compared with analyses in which the spatial variability of the same shear strength data were incorporated using geostatistics. The factors of safety from the probabilistic analysis were log-normally distributed but those from the two geostatistically generated analyses were outside the extreme ranges of the probabilistic data. This emphasizes the importance of any concentrated zones of weak or strong material within a section with the same overall average frictional shear strength values. This is not correctly captured by a purely random strength assignment. The use of other geostatistical analysis techniques such as indicator kriging and conditional simulation are also under consideration to accommodate extreme variations in shear strength as occur over short distances in the china clay host material, kaolinized granite.
A basic downhole geophysical approach to the investigation of shallow mineworkings
Authors: Weston Stephen
Published: April 2008

Present investigations for shallow mineworkings generally consist of a desk study followed by rotary openhole or corehole drilling. The former, although relatively cheap, produces relatively low quality and quantity data. Investigations can maintain a high data retrieval at a low cost by combining openhole drilling with the downhole measurement of natural gamma radiation.

Detailed analysis of these data will allow a more confident interpretation to be made. This includes the correlation of solid mineral seams, collapsed workings and voids, and therefore more precise recommendations can be made. Examples of the benefits of natural gamma logs, rotary openholes and detailed analysis are shown.
Incorporation of information on geohazards into the planning process
Authors: Marker Brian R.
Published: April 2008

Urban areas require geological resources for construction and maintenance. Most of these come from rural areas and are often considered separately from the planning of the urban area. Uncontrolled urban growth may sterilize resources or lead to contaminative activities occurring close to vulnerable aquifers. Foundation problems may influence both rate and costs of urban development and geological hazards may threaten property or public safety. Urban areas may grow across potential problems of their own making, such as waste disposal sites. Such problems can be minimized if (a) development takes place in the right places and is properly designed and executed; and (b) the implications of urban development are considered in the context of the availability and supply of minerals, water and land, and the environmental effects of exploiting these.

To achieve balanced consideration of planning and development options, sound geological and geomorphological information is needed at (a) the site level, for specific developments; and (b) the regional level, to guide general allocations of land for particular uses and alert those designing site investigations to the range of problems to be considered.

Geological and related factors relevant to decision making are often neglected. There have been increasing efforts by geologists to secure adequate basic information for selected urban areas but results often have been presented in a form which does not meet the requirements of planners and other decision makers, who may have had no geological training. Whilst planning of land use in urban areas will always be led by economic, social and conservation pressures, it is important to involve planners in identification of relevant issues and the design and presentation of results.