bluuebunny/crossref_metadata_2025 huggingface dataset:
The examination of encrustations in an unlined borehole using the sidewall sampling technique
Authors: Howsam P. , Brassington F. C. , Lucey P. A.
Published: November 2007

In borehole rehabilitation, engineers usually have limited access to information about the borehole condition and the processes involved. This paper describes the use of the sidewall sampling technique to gain information about some manganese encrustations which are considered to be adversely affecting the yield of a large-diameter, unlined, Triassic sandstone borehole in NW England. Trials with the technique proved successful and suggest that it is worth considering in any rehabilitation feasibility or implementation projects in which similar conditions prevail.
Nomograms for the analysis of recovery tests on large-diameter wells
Authors: Barker J. A. , Herbert R.
Published: November 2007

A set of nomograms has been constructed to facilitate the application of the solution of Papadopulos & Cooper to recovery tests on fully-penetrating large-diameter wells in confined aquifers. The data required are: the well geometry, the abstraction rate and period, the drawdown at the end of pumping and the time taken for 25, 50 or 75% recovery to occur.
Large Byzantine water storage cisterns
Authors: Lerner D.
Published: November 2007

At least 36 cisterns, excavated reservoirs, were constructed in Istanbul during Byzantine times. The largest known covered cistern is the Basilica cistern which was probably completed in the early 6th century. Figure 1 shows a plan view of the 140 × 70 m structure, which now lies partly under a road in a busy area of Istanbul. It was originally supplied by aqueduct from springs in Marmara, west of the city. Figure2 gives a general view of the interior, where the roof is supported by 336 columns.

Figure 3 shows the base of one of the column which appears to be made from a scrap sculpture of the Medusa's head. There are constant inflows of water at various points in the roof of the cistern, as can be seen from the pool of water, splashes and drips. At the time the photograph was taken in March 1988, it had not rained for at least 15 days, hence the inflow could not have been direct recharge. The water was clear and odour-free and was certainly not sewage. The probable source was leaking water mains which, without the cistern, would percolate to the water table. Thus Figure 3 provides some evidence that leaking mains recharge groundwater as argued in recent articles (Lerner 1986, 1988a, b).

My thanks to Professor Okay Eroskay of Istanbul University for help with the photography.
Probabilistic approach for design optimization of rockfall protective barriers
Authors: Paronuzzi P.
Published: November 2007

Many alpine and pre-alpine areas of northern Italy are affected by dangerous rockfall phenomena. In designing rockfall protective barriers it is necessary to estimate the reliability of the defensive structures considering the following input parameters: (i) predicted impact energy field, (ii) possible rock block trajectories and (iii) impact strength of the barrier construction material. The reliability analysis aims at predicting the probability that a rock mass may go beyond the barrier (failure or overfly) or beyond the barrier system. The paper describes a design procedure which involves the evaluation of the probability of occurrence of a specific rock body bouncing down. This moving block is characterized by a certain rock mass (
m
), translation velocity (υ
t
) and rotation velocity (υ
r
). The paper discusses the practical application of a computer block trajectory simulation procedure used to design optimization problems in mountain sites of Friuli which are exposed to rockslide risk.
Seismic delineation of fissures associated with mining subsidence at Houghton-le-Spring, Co. Durham
Authors: Goulty N. R. , Kragh J. E.
Published: November 2007

Immediately north of Houghton-le-Spring, Co. Durham, is a low ridge of Permian Magnesian Limestone overlying the Carboniferous Coal Measures. Running along this ridge is a zone of surface fissures. These fissures are clearly associated with mining subsidence as they are of recent origin and are situated above a near-vertical fault which has acted as a barrier limiting mineworkings to the north and south in several underlying coal seams. Mining adjacent to the fault began in the last century and continued until 1960.

Seismic refraction profiles have been run across the fissured zone using shear and compressional waves. The fissured zone can be identified by its low shear-wave seismic velocity. Furthermore, the boundary of the fissured zone can be accurately located simply by observing the differences in amplitudes of compressional-wave arrivals received at geophones spanning the boundary from an explosive shot in solid ground. These observations could be useful in site investigation, and the seismic method is recommended for detecting similar fissures in brittle sedimentary rock overlying mineworkings.
The oxidation of pyrite in cement stabilized colliery shale
Authors: Thomas M. D. A. , Kettle R. J. , Morton J. A.
Published: November 2007

This paper reports a study into the long-term performance of cement stabilized colliery shale. A total of 16 samples were obtained from various UK collieries chosen to provide shales with a representative range of physical and chemical properties. Cement stabilized specimens produced from these shales were exposed to three different environments. The engineering performance of the stabilized specimens was established through the monitoring of changes in linear dimensions and strength. The sulphur-bearing mineralogy was examined at regular intervals, and the samples were analysed by X-ray diffraction and scanning electron microscopy throughout the study. It is concluded that pyrite, a component of colliery shale, oxidizes in cement stabilized shale. The products of pyrite oxidation may cause distress in the stabilized material through the generation of crystallization pressures or, alternatively, may attack cement hydration minerals. The long-term performance of the stabilized shale is reliably correlated with the original sulphur-bearing mineralogy of the raw shale. Establishment of the limits of total, pyritic and sulphate sulphur are suggested to preclude the use of shales which may cause problems to the long-term durability of cement stabilized colliery shale.
Applications of geomorphology to small hydroelectric schemes
Authors: Birch G. P.
Published: November 2007

Small hydroelectric schemes are often sited in mountainous areas where the natural processes of uplift and erosion are relatively rapid. Significant benefit has been drawn from the application of geomorphology to the siting and design of schemes in Peru. The technique is based on the use of existing air photography to detect processes which could threaten the viability of a proposed site (e.g. active earthflows or river erosion). The information is presented as a 1:5000 scale geomorphology or hazard map which provides the design engineer with an understanding of the likely geotechnical constraints at a proposed site, at low cost and in advance of a site visit.
The attenuation of the organic component of landfill leachate in the unsaturated zone: a review
Authors: Mather J. D.
Published: November 2007

Current philosophies for the landfill disposal of wastes are reviewed. A survey of research and operating experience suggests that in some geological environments biodegradation of organic components is occurring within the unsaturated zone whereas little attenuation occurs elsewhere. The most important factor controlling this biodegradation is the buffering capacity of the strata. Aquifers with a significant carbonate content are able to buffer acid leachates favouring the development of microbial populations and leachate attenuation. The lack of buffering capacity within many Permo-Triassic Sandstones maintains acid conditions and limits the development of biodegradation reactions.
CBR and shear strengths of compacted laterite soils from southwestern Nigeria
Authors: Ogunsanwo Olufemi
Published: November 2007

Laterite soils derived from the basement complex and sedimentary areas of southwestern Nigeria are compacted at the energy of the standard Proctor. The compacted laterite soils possess unsoaked and soaked California bearing ratio values that make them adequate for use as sub-base materials. Their shear strengths are quite high under total and effective stress conditions and thus with their acceptable permeability level the soils are suitable for use in the construction of embankments and dams.
Devensian periglacial influences on the development of spatially variable permeability in the Chalk of southeast England
Authors: Younger P. L.
Published: November 2007

In unconfined parts of the Chalk aquifer in southeast England, permeability generally varies laterally with the lowest permeabilities occurring beneath interfluve areas, and the highest beneath river valleys and dry valleys. Furthermore, the Chalk in the river valleys is normally in excellent hydraulic continuity with the overlying highly permeable Quaternary gravels. However, recent field investigations in the Thames Valley have demonstrated the existence of zones of anomalously low Chalk permeability associated with the development of thin discontinuous confining layers of low permeability ‘putty chalk’ at the gravel-chalk interface. Hitherto putty chalk in the Middle Thames Valley has mostly been reported from interfluve areas where it can occur as a periglacially frost-weathered mantle on the upper surface of the Chalk. The true extent and hydraulic significance of putty chalk in valley bottom positions is only now being realised. Existing models for the lateral variation in Chalk permeability cannot explain these new observations. A new model is therefore proposed in which it is envisaged that, during the Devensian, carbonate dissolution in perennial taliks (unfrozen zones) beneath the major channels of the braided palaeo-Thames caused the high-permeability zones, while permafrost beneath the interfluves restricted dissolution at those sites. Freeze-thaw action in seasonal taliks beneath minor channels would account for the formation of putty chalk at the gravel-chalk interface, and the persistence of permafrost beneath these seasonal taliks would lead to a restriction of dissolution, and thus to a zone of low permeability.
A note on the distribution, levels and temperatures of minewaters in the Northumberland and Durham coalfield
Authors: Harrison R. , Scott W. B. , Smith T.
Published: November 2007

This Technical Note presents basic data on water levels, extraction rate and temperatures of minewaters in the Northumberland and Durham Coalfield. The data were collected during a survey of the coalfield undertaken for British Gas who have an interest in utilizing groundwater sources for heating gas at pressure reduction stations.
Examination of erosion resistance of clays in embankment dams
Authors: Atkinson J. H. , Charles J. A. , Mhach H. K.
Published: November 2007

Internal erosion is a possible cause of failure in embankment dams. Erosion may occur when soil in the vicinity of a Crack disperses into suspension and is transported by the water into the drainage system. An important factor in assessing the potential of a soil for dispersion is the true cohesion defined as the strength at zero effective stress. A new test, the cylinder dispersion test, has been developed to investigate true cohesion and dispersion in soils. Tests carried out on a number of different soils demonstrated the major influence of the pore water chemistry on the true cohesion and dispersion properties, and hence erosion resistance.
Application of marine seismic surveying methods to engineering geological studies in the near-shore environment
Authors: Dobinson A. , McCann D. M.
Published: November 2007

This paper discusses the application of various marine geophysical techniques to engineering studies in coastal and estuarine environments. Sea bed morphology can be examined using echo sounding and sidescan sonar whilst geological structure is investigated using continuous seismic profiling surveys based on sparker and boomer sources. In both cases samples of sea floor sediments and rocks are collected and boreholes drilled to calibrate the seismostratigraphy in terms of geological structure. Current geophysical equipment and methods are reviewed and are illustrated by three case histories. The first describes a geophysical survey undertaken in the Wash to provide information on sediment movement as part of a feasibility study for bunded reservoir construction. The second discusses an appraisal of the engineering characteristics of the near-shore environment carried out in connection with coastal engineering studies in Lyme Bay, Dorset. Finally, a description is given of a survey which formed part of a study to investigate the distribution of sand and gravel aggregate resources off the East Anglian coast.

Whilst there have been continuous improvements in seismic profiling equipment and survey techniques, most of the underlying principles and interpretation techniques have remained the same. By combining the results from marine seismic surveys and geological sampling programmes it is possible to achieve an accurate assessment of the sub-bottom geology in the near-shore environment.
Modification of the formula used in the determination of the ten per cent fines value of aggregate
Authors: Bullas J. C.
Published: November 2007

One established method of estimating the force required for the ten per cent fines test on an aggregate is to divide the number 4000 by the aggregate impact value. However recent analysis of ten per cent fines and aggregate impact data for 79 aggregate samples of various rock types suggests that this method commonly produces too high a fines yield. From the present work it appears that use of the value 2800 in the place of 4000 would increase the probability of a valid estimate of the test load.
Shallow reflection seismic-where are we now?
Authors: Morris D. B. , Barker R.
Published: November 2007

Shallow reflection seismic surveys, which are now regularly carried out by several universities and companies in the UK for site investigations, were the subject of a well attended meeting held in the School of Earth Sciences at the University of Birmingham on 25 October 1989. The meeting was organised on behalf of the Geological Society's Joint Association for Geophysics (JAG) because of the recent increase in the use of reflection techniques to investigate shallow geological structures down to depths of 100 m or more.

Several groups from the USA, Europe and the UK have been involved in the rapid development of the technique since digital recording instruments and portable PCs became available. This meeting brought together groups from the Universities of Birmingham, Leicester, Leeds, Cardiff and Reading and the British Geological Survey to discuss a wide range of problems and applications, and was attended by more than 70 delegates.

Introductory talks by R. King (Birmingham) and I. Hill (Leicester) described the basic principles behind the technique and showed that good results could be achieved with standard portable seismic instruments. High-frequency geophones are generally laid out at 2 m to 5 m intervals from a source of high-frequency energy such as a buffalo gun (Leicester University) or a sledge hammer (preferred by Birmingham). The seismic energy returning to the surface after a reflection at sub-surface interfaces is recorded in digital form for later processing. Field techniques are designed to enhance the strength of the signals.

Although much of the sophisticated data
Port Solent Marina, Portsmouth, UK
Authors: Privett K. D.
Published: November 2007

Port Solent is a waterside development of a 36 hectare site at the north end of Portsmouth Harbour occupying what used to be the shallow, impounded Paulsgrove Lake and surrounding derelict land (SU635052). The existing lake level was lowered and approximately 310000 m
3
of accumulated silt and other unsuitable material were removed. This exposed a formation of reworked (probably soliflucted) chalk overlying deeply frost-shattered, structureless chalk, becoming more structured with depth. Groundwater was artesian and it was only the cohesive fraction of this material which prevented instability.

A total of 2.2 km of in situ concrete retaining wall was constructed and approximately 600 000 m
3
of imported fill placed to a maximum thickness of 5 m for land reclamation behind the wall. Chalk from the nearby Ports Down Hills was chosen as the fill material, from quarries at Warren Farm (SU603072), Downend (SU601066) and Paulsgrove (SU635066). An experimental excavation and embankment were used to formulate the method of working and supported by initial site trials a compaction specification was developed for 450 mm and 600 mm thick layers of chalk (
Privett 1990
). This ‘reduced effort’ compaction specification preserved the lump structure of the chalk and was designed to allow placing of chalk in adverse conditions where more severe compaction requirements would have caused problems of instability. The chalk was successfully placed on the relatively soft formation with artesian groundwater and throughout the winter season, sometimes in shallow standing water.

The integrity of the chalk fill was monitored by
Microtremor networks and seismic hazard assessment in the UK
Authors: Aspinall W. P. , Skipp B. O. , Ritchie M. E. A.
Published: November 2007

Microtremor networks have been instituted by the CEGB around the potential sites of PWR nuclear reactors at Hinkley Point in Somerset, Dungeness in Kent and at two locations in north Wales, as part of a programme for the assessment of seismic hazard. Critical attention has been paid to the quality of the data obtained and advantage has been taken of recently developed software to explore the confidence which can be attached to the findings of the networks. During the periods of operation of the networks eight microearthquakes have been recorded within 60 km of Hinkley Point and 22 close to the north Wales sites, but none within 60 km of Dungeness. Magnitudes range from 2.9 M
L
down to -0.5M
L
. Well constrained hypocentre locations indicate that mid- and lower crustal depths of origin are most common in the first two areas. Focal mechanism solutions for these events suggest that ‘mixed mode faulting’ characterizes current tectonic behaviour in both areas. These findings are exemplified by results from the Hinkley Point network. The direct and indirect implications for hazard evaluation procedures are discussed.
Experimental investigation of crosshole seismic techniques for shallow coal exploration
Authors: Goulty N. R. , Thatcher J. S. , Findlay M. J. , Kragh J. E. , Jackson P. D.
Published: November 2007

Three crosshole seismic surveying techniques have been investigated using boreholes on opencast coal exploration sites in northern England. The objective has been to determine their potential for locating old mineworkings and small-scale geological structures. The first method was to propagate seam waves between boreholes, with source and receiver at seam level, to check for coal seam continuity. This method was found not to be viable because of the strong attenuation of high-frequency shear waves in shallow strata. The second and third methods shared a common field technique, with shots at several levels in one borehole recorded on an array of receivers in a neighbouring borehole. Processing the traveltime data for only the seismic first arrivals constitutes a tomography survey. Although careful processing produces a reasonable image of the velocity structure, the tomographic method is not sensitive enough to detect changes in seismic velocity due to subsidence above old workings. However, processing the reflected arrivals from one of the tomographic datasets has produced a seismic section with a vertical resolution of less than 2 m. It is suggested that, in conjunction with hole-to-surface seismic surveys, the crosshole seismic reflection method could complement exploration boreholes in a variety of exploration and site investigation applications.
Locating the Sherwood Sandstone aquifer with the aid of resistivity surveying in the Vale of York
Authors: Hawkins T. R. W. , Chadha D. S.
Published: November 2007

The Sherwood Sandstone aquifer in the Vale of York is generally confined beneath thick clay drift in the west and by thin drift plus an increasing thickness of Mercia Mudstone towards the east. Published geological maps show a gentle easterly dipping succession cut by one major east-west fault passing through Stamford Bridge. The junction between the Sherwood Sandstone and the Mercia Mudstone is shown by a north-south trending line south of this fault. Recent boreholes for water supply have shown that the structure is more complex however, and reliable predictions of depths to the aquifer frequently cannot be made without pre-drilling surveys. Consequently the results of over 50 resistivity sounding have been used in conjunction with all available well logs to redraw the important hydrogeological boundary between the Sherwood Sandstone and the Mercia Mudstone across the central part of the Vale. The results have shown that depths to the aquifer, up to around 200 m, can generally be predicted prior to drilling to within 100y surface resistivity methods, except where the ‘Mudstone’ is very thin in the ‘feather-edge’ zone. The results have also shown the presence of many persistent east-west or northeast trending faults with vertical throws up to 80 m and some strike faults or monoclines in this part of the Vale. The significance of these faults to groundwater flow and water extraction are discussed. Wireline logs at six wells suggest the occurrence of at least two thick units of gypsum and anhydrite within the Mercia Mudstone. These cause high, 100-150 ohm m, depth averaged resistivity values to be computed for the Mercia Mudstone.
Soil gas surveying of chlorinated solvents in relation to groundwater pollution studies
Authors: Bishop P. K. , Burston M. W. , Lerner D. N. , Eastwood P. R.
Published: November 2007

Soil gas surveying is a method gaining in popularity for groundwater chlorinated solvent pollution studies, particularly in the USA. Previously published methods have advocated on-site analysis; this study presents a simple method where samples are transported to a laboratory for analysis, hence minimizing the need for specialized field analytical equipment and trained field personnel. Tests show the method provides reliable results, comparable with those of established on-site analysis methods. The soil gas surveying method has been applied to a contaminated industrial site where it was successful in defining an area of significant chlorinated solvent pollution. Preliminary analyses from investigation boreholes indicate that this area has severe groundwater pollution.
Interpreting recovery data from pumping tests
Authors: Herbert R.
Published: November 2007

The shape of hydrographs of the recovery of well water levels for pumping tests in confined aquifers is shown to depend on well storage. This demonstration suggests that the standard method of interpretation of such recovery curves, as described in Todd, will not give accurate values unless the time after start of recovery is greater than about 25
R
c
2
/
T
(see text for notation). Further, it is also demonstrated that if a leaky (low permeability) layer lies above or below the pumped aquifer the recovery curves can be modified significantly and are liable to misinterpretation.
Mackintosh-vs-vane estimation of undrained shear strength correlation for a Sabkha Clay of Saudi Arabia
Authors: Hossain Delwar , Ali Kamal Mohammad
Published: November 2007

The results of field vane shear tests and Mackintosh probings in the soft clay of Obhor Sabkha, Saudi Arabia have been compared and correlated. It is observed that Mackintosh probing is less affected by the presence of gypsum crystals than vane testing and that an approximately linear correlation is possible between the undrained shear strength of this clay measured by a field vane and the
M
-value obtained from Mackintosh probing.
Editorial
Authors: Hawkins A. B.
Published: November 2007

As we approach the 25th anniversary of the publication of QJEG it is appropriate to consider the style and content of the Journal and how it reflects the changing nature of both the academic and practical engineering aspects of applied geology.

The first issue of the
Quarterly Journal of Engineering Geology
was published on 20 September 1967. Its range of interest was to include the whole spectrum of ‘subjects within the field of geology as applied to civil engineering and mining practice’. In his foreword Professor J. E. Richey commented that ‘the variety of subjects treated is one of the noteworthy points about the publication’; an observation still true more than twenty years later.

The Board is pleased that the high reputation of QJEG amongst British workers has extended worldwide; a significant proportion of the papers published in recent volumes have been submitted by foreign authors. It is our intention that the Journal should extend its international coverage and we hope that our efficient service, high production quality and circulation of 2500 in 46 countries will encourage authors to use QJEG as the most appropriate avenue for disseminating their leading papers to an international audience.

In the 1970s an increasing number of hydrogeology papers appeared in the Journal, aided no doubt by the activities of the flourishing Hydrogeological Group of the Geological Society. This was acknowledged in 1979 when the words ‘Encompassing Engineering Geology and Hydrogeology’ first appeared on the front cover of Volume 12. In an editorial in that
Channel Tunnel: UK undersea crossover
Authors: Birch G. P.
Published: November 2007

Background

To permit interchange between running tunnels, primarily to facilitate tunnel maintenance, the Channel Tunnel project incorporates two crossover caverns positioned under the Channel about a third of the way out from each portal.

At the location of the UK crossover the service tunnel, normally positioned between the two running tunnels, deviates below and to the side to enable the running tunnels to come into juxtaposition over a distance of some 500 m. The central portion of this run is opened out as a single cavern measuring 165 m long, 22 m wide and 15 m high—large enough to accommodate a five-storey building and probably the largest undersea cavern built to date.

Geological setting

The cavern is located within clayey carbonate mudstone sequences which straddle the boundary between the Chalk Marl (Lower Cenomanian) and the Gault Clay (Albian). The cavern crown is some 35 m below the seabed, the intervening strata comprising Chalk Marl overlain by the more fractured and therefore more permeable Grey Chalk which is weathered to within 20 m of the cavern crown.

The unconfined compressive strengths of the materials fall within the range 2 MPa to 16 MPa with the highest values being associated with limestone sponge beds in the Chalk Marl and the significantly stronger calcareous sandstone of the Tourtia or Glauconitic Marl.

Formation mass permeabilities are within the region of 1 × 10
-7
m s
-1
and 6 × 10
-9
m s
-1
at the cavern horizon, rising to in excess of 3 × 10
-6
m s
-1
in the
Geotechnical phenomena associated with piling in Hong Kong
Authors: Malone A. W.
Published: November 2007

The paper is a compilation of published accounts of geotechnical phenomena associated with piling in the various geological formations of urban Hong Kong. The occurrence of some of these phenomena may give rise to design and performance problems or construction difficulties. The paper examines the extent to which these problems and difficulties are addressed in traditional pile design. Limitations of traditional practice are identified and remedies are suggested.
Chemical and biochemical weathering of pyritic mudrocks in a shale embankment
Authors: Pye K. , Miller J. A.
Published: November 2007

Following the partial collapse of a shale embankment in Derbysllire, a detailed mineralogical, chemical and electron microscopical investigation was carried out to establish whether the crushed mudstone fill had been significantly affected by chemical weathering after emplacement. Samples of unweathered and weathered Namurian mudrocks from the area were also analysed for comparison and laboratory experiments carried out to simulate abiotic and biochemical shale weathering.

It is concluded that chemical alteration of the shale is a rapid process and that significant post-emplacement chemical and mineralogical changes occurred in the embankment fill. The main reactions involve oxidation of framboidal pyrite, leaching of carbonates by sulphuric acid, formation of authigenic sulphate and iron hydroxide minerals, and leaching of cations from clay minerals. In parts of the fill forming the outer shoulders of the embankment, up to 10lume loss may have occurred due to acid leaching.
Sulphate increase in laboratory prepared samples
Authors: Hawkins A. B. , Wilson S. L. S.
Published: November 2007

Introduction

In February 1990 a large number of acid soluble sulphate analyses of Lias Clay samples were undertaken to determine the possible significance of sulphate in causing ground heave. Sub-samples of approximately 100 g were dried and powdered and representative 2g aliquots removed for analysis as recommended in BS 1377: 1975. The remaining powdered material was retained in glass bottles and stored at room temperature. In July 1990 a further analysis of the material was undertaken. In all but two of the twenty-eight powdered samples there was an increase in the acid soluble sulphate content.

Background

The samples were taken from an almost flat Lias Clay site where it was believed disseminated pyrite would. be present in the dark mudstone/silty clays. In 1987 Hawkins and Pinches drew attention to the increase in acid soluble sulphates over the seventeen-month period in which dark mudstone samples had been stored in the laboratory. In view of this, prepared Lias samples which had been taken at 200 mm vertical spacings from two of the trial pits were re-analysed after a five-month period of storage.

Analytical results

The SO3 percentages measured in February and July 1990 on the powdered samples from TPs A and B are given in Table 1. In the case of TP A low SO3 percentages were obtained on both occasions to a depth of 2.2 m, below which the acid soluble sulphates rose rapidly to about 5%. An increase was noted at each depth, a maximum of 0.50eing recorded at 2.85
Geological materials in construction: an introduction
Authors: Hawkins A. B.
Published: November 2007

To celebrate the tenth anniversary of the setting up of the geomaterials research and graduate training centre at Queen Mary and Westfield College, a conference was held in November 1989 entitled
Geological Materials in Construction: Developments in Geomaterials Research and Practice.
Most of the presentations were from current or past staff, research students and those who had completed the MSc course and were now working in the geomaterials industry. The papers concentrated on the practical research undertaken and drew attention to the increasing importance of geomaterials in the construction industry.

In most universities academic courses on economic geology deal mainly with mineral resources (high-cost/ low-volume) and fuels (coal and oil) rather than the low-cost/high-volume commodities such as aggregates. Other institutions, however, have appreciated the practical reality of an aggregate industry which is not only expanding but is in fact of great economic importance. The high-cost/low-volume minerals are frequently found in only limited areas of the world; the position of the deposits and their genesis is clearly of interest as an academic study. In contrast, however, most countries are relatively self-sufficient in geomaterials, even though the quality may vary from country to country and area to area. As there is relatively little international trade, many economic geology textbooks do not deal adequately with the low-cost/high-volume materials and consequently their value is frequently under-rated.

Within individual countries, however, transportation is often required. In the southeast of England, for instance, river terraces are the main source of aggregate and in many places these
Concrete petrography: a review
Authors: French W. J.
Published: November 2007

Concrete strength depends on the amount, composition and quality of the hydrated binder to the fine and coarse aggregate. This paper reviews the way in which concretes can be examined with the petrographic microscope using both thin sections and polished plates. It reports observations made on actual samples, noting the similarity between the densities obtained by petrographic assessment and those established in laboratory tests.

The paper highlights the value of carrying out a petrographic investigation to obtain quantitative information in support of and prior to the conventional chemical investigation, including aggregate/cement paste ratio and void content, assessment of the weight fractions of water, cement and aggregate; assessment of the composition of the binder including the slag to Portland cement ratio, assessment of the PFA to Portland cement ratio and possibly the assessment of the type of Portland cement employed in the mixture. Attention is also drawn to the implications of aggregate shape and grading.
A mechanism of marble staining
Authors: Hunt B. J.
Published: November 2007

An investigation was carried out into the cause of marble staining within the inner courtyard of a large structure in Bahrain. Thick sealant strips which infilled particular joints of a marble floor were shown to be susceptible to breakdown by alkaline solutions, from which an organic material that contained a coloration had been derived. The alkaline solutions appeared to have originated from the underlying bedding mortar cements. These solutions had then been drawn to the surface by a form of capillary action. With successive cycles of alkaline solution attack of the sealant strips, the organic material which contained the coloration had apparently spread across the marble surface as a thin film.
Quality and durability of stone for construction
Authors: Sims Ian
Published: November 2007

The use of natural stone materials in construction is now experiencing a marked revival particularly for external claddings. In contrast with most other construction materials, there are few British Standard tests for natural stone or Standard specifications defining the minimum quality requirements for various purposes. The Code of Practice for cladding is inadequate in these respects.

The range of test methods provided by ASTM and the complementary series of Standard specifications covering the major stone families are summarized but none of these directly address durability. Selected quality assessment procedures from German, Italian and other European practices and a number of different approaches to the evaluation of durability of stone are critically reviewed. The crucial importance of representative samples in such evaluations is recognized but the aspects of source selection and sampling are not discussed in detail.
The future of aggregate extraction and evaluation in Europe
Authors: Fox R. A.
Published: November 2007

Introduction

The construction industry in Europe has been extremely buoyant in the past four to five years, particularly in the UK, Spanish, French and Dutch markets. Even in West Germany the difficulties experienced until 1987 appear to have been overcome and demand for aggregates is likely to be more than the 516 Mtonnes of 1988. Thus, with some 12 0rowth in the European construction industry predicted for 1989, there would appear to be great potential for the future. Table 1 gives production figures for some EEC countries.

In the UK aggregate production rose to 270 Mtonnes in 1988, surpassing the previous record of 256 Mtonnes set in 1973. Crushed rock aggregate production at 154 Mtonnes now exceeds sand and gravel production by approximately 40 Mtonnes and seems likely to be the major source of UK aggregates for the future.

Planning control on extraction

The major Constraints on the development of any new aggregate source are those related to agriculture, landscape and ecology, with both nationally and locally based policies influencing the allowed extraction. Such constraints may restrict mineral working but are rarely an absolute bar to the granting of planning permission. However, despite a 40 0ncrease in production of aggregates in the 1980s there are few signs that local planning authorities are prepared to accept that the demand for aggregates should be provided for within their county and it is difficult to see how the increasing demand should be met.

Marine aggregates supply some of the needs of coastal markets
A new system for the objective interpretation of third-party data in assessments of regional sand and gravel resources
Authors: Morey A. J. , Stevens P. F. , Sanders M. K.
Published: November 2007

A comprehensive desk study was recently carried out to assess the potential resources of sand and gravel in the drift deposits of County Durham. The study was based on published information, limited field observations and the analysis of 6000 subsurface datapoint references and over 1700 particle size distribution results. It was necessary, therefore, to devise a system of analysis which could provide an objective and repeatable assessment of the sand and gravel deposits and their resource potential on a regional basis.

The evaluation system previously adopted by the Industrial Minerals Assessment Unit (IMAU) for the sand and gravel resource assessments conducted by the British Geological Survey was reviewed. This system comprises a statistical procedure to classify the investigation data and gives arbitrary physical criteria to determine whether a deposit can be regarded as ‘potentially workable’.

The principal data available to the IMAU for each of their resource assessments were specifically gathered for the project under their direct supervision. The IMAU system could not be applied to the Durham study because data for this study were obtained totally from third-party sources.

A system of analysis was designed which was sensitive to the variation in data quality. It is based on a flow chart comprising both question/answer and action elements and incorporates the arbitrary physical criteria adopted by the IMAU. The system is described in this paper and the effectiveness and limitations are demonstrated with reference to the Durham study.
The Carboniferous Limestone of the Bristol area: a review of the influence of the lithology and chemistry on its use as a geomaterial
Authors: Al-Jassar S. , Hawkins A. B.
Published: November 2007

Ninety-three rock samples were collected from the Carboniferous Limestone in the Clifton Gorge, Burrington Combe, Brean Down and temporary faces in Wick and Chipping Sodbury quarries. The samples were cut and peels taken to allow a petrographic description. The samples were tested for their unconfined compressive strength. Wet chemistry and X-ray diffraction were used to establish the rock mass chemistry and the nature of the insoluble residue. Attention is drawn to potentially alkali reactive constituents and the need to ensure that due consideration is given to the nature of the aggregate used in concrete manufacture.
Lessons from Loscoe: the uncontrolled migration of landfill gas
Authors: Williams G. M. , Aitkenhead N.
Published: November 2007

In March 1986 a house at Loscoe in Derbyshire was completely destroyed by a methane gas explosion, badly injuring the three occupants. Eight months later at a Public Inquiry, the sequence of events leading up to the incident was established and evidence produced to ascertain the origin of the methane. During the proceedings it became apparent that signs of ground heating had been detected approximately 100 m beyond the boundary of a near-by landfill some years before the explosion but that the phenomenon had been misinterpreted as a shallow burning coal seam. Had the geology of the area and the geochemistry of methane been known to the investigators at that time, it is possible that the landfill would have been identified as the source of methane and the Loscoe area protected from the dangers of uncontrolled gas migration.
The legacy of aquifer pollution by industrial chemicals: technical appraisal and policy implications
Authors: Lawrence A. R. , Foster S. S. D.
Published: November 2007

The problem of groundwater contamination by the common chlorinated industrial solvents is becoming increasingly apparent in Britain. Pollution is known to have occurred widely as a result of casual or accidental discharge of such chemicals over many decades. Two case histories demonstrate that the combination of solvent physicochemical properties and Chalk hydrogeological characteristics can result in both extensive transport and extreme persistence in this aquifer.

Adequately proving the source of groundwater contamination is onerous. Individual pollution problems are equally likely to be the legacy of past industrial activity as the effect of current industrial practice. At least in its most direct sense this renders the ‘polluter-pays’ principle ineffective. The situation is further complicated by the technical difficulty, excessive cost and inadequate definition of aquifer restoration. Modifications and clarifications to policy are required to provide a more rational basis for the alleviation of this ground-water pollution problem.
WRc/Soil Survey inert suction sampler
Authors: Clark L. , Gomme J. , Carter A.
Published: November 2007

As part of a survey of pesticides in the UK Major Aquifers, which WRc are undertaking on behalf of the National Rivers Authority, a site at Assarts Farm near Mansfield on the Sherwood Sandstone aquifer has been selected for the study of pesticide movement in the unsaturated zone of the sandstone aquifer.

A difficulty in studying pesticide movement in the unsaturated zone is the need to obtain large volumes of water for analysis. WRc, in co-operation with the Soil Survey and Land Research Centre (SSLRC) has tackled this problem by using a modification of the SSLRC standard soil moisture suction sampler. The modified design (Fig. 1), manufactured by SSLRC, is intended to render the installation as chemically inert as possible, so the sampler shell is of stainless steel, tubes and caps of Teflon and the filter element ceramic. No adhesives or resins were used.

At the design stage it was anticipated that each sampler would yield between about 100 ml and 500 ml depending on the soil moisture at the time of sampling. In order to be able to obtain the necessary volume of water (1.71 for three groups of pesticides) needed to analyse pesticides to the required detection limit, a total of twelve samplers in four clusters (Table 1) of three have been installed. It was intended that under optimum conditions each cluster of three samplers, when bulked, would provide sufficient water for one analysis. Under progressively drier conditions, the samples from the clusters may need to be bulked
Determination of the influence of joint orientation on rock mass classification for tunnelling using a stereographic overlay
Authors: Francis T. E.
Published: November 2007

Rock mass classification systems are commonly employed during exploration for rock tunnels. Joint orientation is an important input, affecting blasting, span widths, roof support and groundwater flow. When using Bienawski's geomechanics classification system, the favourability of joint orientations with respect to tunnel drive direction must be selected. As joint populations are generally plotted stereographically, an overlay has been prepared on which sectors defining favourability in terms of the geomechanics classification are delineated. Superimposition of the favourability overlay on a joint pole counter plot allows easy assessment of the effects of joint set orientations.
Stabilization of a dispersive soil by blending with fly ash
Authors: Indraratna B. , Nutalaya P. , Kuganenthira N.
Published: November 2007

This paper is concerned with the influence of fly ash (pozzolanic) on the stabilization of a dispersive soil commonly found in northeast Thailand. The effect of various proportions of fly ash on the rate of erosion, dispersiveness, strength and frictional properties and the compaction and consolidation characteristics, are discussed. It is noted that in general the addition of fly ash not only inhibits erosion and dispersiveness but also contributes to a significant improvement in strength and deformation characteristics. Nevertheless, excessive quantities of fly ash (>8%) generate diminishing returns and in fact promote segregation (erosion) of the stabilized soil again due to insufficient cohesion. Mineralogical studies based on X-ray diffraction analysis indicate that the reduction in the rate of erosion of the blended soil is associated with fine particle flocculation. The long term properties, however, are directly linked with the self-hardening nature of fly ash which contributes to time-dependent strengthening of the stabilized soil.
Modelling of faulted rock mass response to glaciation, thermal loading and seismicity
Authors: Stephansson Ove , Shen Baotang
Published: November 2007

Faulted rock mass response to glaciation, thermal loading and earthquake is modelled numerically by the distinct element method. The modelling results are applied to the stability and safety of a potential nuclear waste repository in hard rock. The fault deformations caused by glaciation are significantly influenced by the initial stress conditions. The thermal loading and the earthquake response cause deformation of faults and are likely to influence the groundwater flow.
The use of dating techniques to constrain the age of fault activity: a case history from north Somerset, United Kingdom
Authors: Gutmanis J. C. , Hailwood E. A , Maddock R. H. , Vita-Finzi C.
Published: November 2007

Attempts were made to obtain absolute ages constraining the most recent episode of fault activity in the North Somerset Coastal Fault Belt as part of the seismic hazard assessment for the proposed Hinkley Point ‘C’ power station. Radiometric (uranium series,
14
C) and palaeomagnetic dating techniques were applied to calcite from vein systems which cut the Hinkley Point Fault and
14
C dating was applied to bone material from undeformed Quaternary gravel deposits overlying faults in Liassic bedrock at Helwell Bay. Detailed field mapping and microscopy indicated that the samples chosen for dating had not undergone any significant fault-related deformation. Dates obtained from the radiometric techniques ranged from
c
. 33 ka to greater than 300 ka and reflect the influences of isotopic exchange and contamination as well as the inherent age limitations of the techniques. Palaeomagnetic dating techniques identified reverse polarizaton in a calcite sample from the Hinkley Point Fault, indicating an age greater than 730 ka, the time of the last geomagnetic field reversal. Palaeomagnetic vectors suggest a pre-Pliocene (and conceivably an early Jurassic) age for the calcite vein emplacement.