bluuebunny/crossref_metadata_2025 huggingface dataset:
Geomorphology and foundation conditions around Grangemouth
Authors: Sissons John Brian
Published: November 2007

Study of the geomorphic history of the Grangemouth area, based particularly on borehole data, has revealed a series of relative sea-level changes. Each major change in sea-level resulted in a particular set of drift deposits and, in one instance, in widespread marine planation. Through an understanding of the geomorphic history of the area some 2000 drift borehole records have been correlated and the areal and altitudinal limits of various deposits established. Much of this information can be portrayed on simple maps of value in site investigations and in local and regional planning. It is suggested that many badly planned site investigations involving expensive boring operations could be avoided not only in this area but in the country as a whole if such maps were available. This problem could be dealt with by the establishment in a centre such as the Institute of Geological Sciences of a computer data bank of drift borehole records linked with an advisory service staffed by suitably qualified specialists.
The geological setting of the bridges of the Lower Tay Estuary with particular reference to the fill of the buried channel
Authors: McManus John
Published: November 2007

Three bridges span the lower Tay estuary at Dundee. Construction techniques and geo-technical exploration differed with each of the bridges. Aspects of scour and channel migration are considered with respect to foundation depth of the early bridges. Buried channels and fill patterns reveal details of late glacial history related to three repeated histories of estuarine sedimentation.
A new technique of vane testing
Authors: Denness Bruce , Green Michael William
Published: November 2007

A means of detecting sample disturbance and the anisotropy of undrained strength of clay soils by use of the standard vane is presented. If the sample is appreciably disturbed it is not possible to derive any values for the anisotropy of undrained shear strength from the analysis. The technique permits the determination of this anisotropy using only one vane by considering the elliptical distribution of strength in a plane perpendicular to bedding.

The standard vane, with a length/breadth ratio (
k
) of 3/2, theoretically permits the determination of an average strength within 18 per cent of the true value for real soils depending on the angle of insertion. A vane with
k
= 2/3 is theoretically the least sensitive to anisotropy of strength and would consequently be the best shape for determining an average value in preliminary investigations. For real soils the average strength recorded would be within
2
per cent of the true value no matter what the angle of insertion of this vane.
Sample representability
Authors: Fookes P. G.
Published: November 2007

1. Introduction

F
or the engineering geologist
, site investigation forms a vital part of the project feasibility study and his role in investigation is usually concerned with the planning and perhaps control of the aspects of the fieldwork. As a member of the project team his particular contribution is based on a thorough grounding in the fundamentals of geology and his working knowledge of the requirements and procedures of foundation engineering.

Considered in rather broad terms, site investigation has two main objectives—firstly to obtain a qualitative picture of the sub-surface conditions in the project area and secondly to obtain quantitative estimates of the engineering properties of the soils and rocks. The latter is used in the analytical predictions of the behaviour of the proposed construction (Davis & Poulos, 1967).

In this contribution only one aspect of investigation will be considered, that is the taking of samples in the field. It has long been recognised by engineers that the actual method used to obtain the sample during an investigation is of major significance to the accuracy and value of the test results subsequently obtained in the laboratory. The disturbance which the sample
*
receives during its collection directly affects the engineering properties of the test specimens. Broadly speaking this effect is at a minimum in hard rocks, e.g. granite, and is at a maximum in sediments or soils, e.g. soft clay. The comments which follow are therefore largely concerned with clayey sediments. Not only has much work been done on these materials, but
Superficial structures in reconnaissance and feasibility studies
Authors: Higginbottom I. E.
Published: November 2007

I
n reconnaissance and feasibility studies
the geological information available to the civil engineer usually comprises the official geological map/maps showing, in an idealized manner, the distribution of the main ‘solid’ formations and superficial ‘drift’ deposits. Certain broad inferences regarding the three-dimensional structure of these formations can generally be drawn. However, the civil engineer is most often concerned with the geotechnical properties of the near-surface zone, and it is within this zone that the processes of weathering, gravitational movement, post-erosional stress relief, etc., operate most effectively. These processes often cause local departures from the situation depicted on the map. Failure to appreciate the possible range and extent of these changes underlies many of the past misapprehensions held by civil engineers of the value of geological information. From his knowledge of geological processes however, the engineering geologist should be able to make useful predictions concerning those departures from the mapped situation that might be expected in a particular area, and to devise investigational techniques best suited to disclose them, since most smaller superficial structures are not directly discernible from surface evidence in the course of routine geological mapping.

Effects due to the surface-operating agencies mentioned above may form only a transient stage in a continuously changing situation, leading from simple fracturing through increasing degrees of structural disturbance, to the complete redistribution of the original deposit and the creation of an independently recognizable superficial deposit, as for example in the process of solifluction. However, it is proposed to limit this short account
Author's reply to letter from S. C. A. Holmes
Authors: McDowell P. W.
Published: November 2007

Mr. Holmes seems to have missed the point of this paper by implying in his letter that the resistivity results were interpreted without reference to the available geological information, but based only upon the preliminary borehole information.

The main reason for the publication of this particular case history was the availability of information from holes drilled both before and after the resistivity survey. This enabled the advantages and limitations of the methods to be assessed for this particular site.

In the introduction a simple geological section based upon three boreholes was drawn to show how such sections are unfortunately drawn up from borehole information, with little reference to available geological information. The author, well aware of the varied lithology of the area, carried out the resistivity survey to prove and possibly define this variability.

The remarks of Mr. Holmes concerning the importance of careful literature study at an early stage of site investigation are, however, heartily endorsed.
The planning of site investigations for highways
Authors: Wakeling Thomas Roy Maylor
Published: November 2007

A site investigation covers three stages, a preliminary appreciation of the site, a ground investigation in which borings and laboratory testing are undertaken, and a final stage in which the conclusions of the ground investigation are checked against the actual ground conditions as revealed by the constructional excavations. This paper considers the planning and implementation of the ground investigation under conditions normally prevailing in the British Isles.

Various procedures are described for boring in soils and rocks, for trial excavations, for probing, and for geophysical surveying. Sampling procedures are considered on the basis of the quality of the sample thus obtained. Sample quality ranges between almost fully-undisturbed soil samples as taken by a thin-wall piston sampler, and fully disturbed samples taken from the drill tools.

The choice of procedure for boring and sampling is determined by the technical requirements of the investigation, by the practical problems arising from site conditions and by economy. It is considered that investigations should start using standard equipment and that the more sophisticated and expensive procedures should be employed only when the nature of the geotechnical problem has been determined.

The paper concludes with a discussion of the management and organization of site investigations.
The planning and implementation of a site investigation for a highway in tropical conditions in Fiji
Authors: Lovegrove Geoffrey William , Fookes Peter George
Published: November 2007

The paper outlines the planning and implementation of a site investigation carried out on a limited budget for 110 miles of proposed new highway in Fiji. A comparison is drawn between the cost of investigation of earthworks and general foundation conditions, rock materials, and engineering structures, estimated during the planning stage by allocating funds in the same proportion as the estimated construction cost, and the actual cost of investigation of each. The programming and staffing of the investigation are considered.

Examples are quoted showing how economical results were obtained by the use of geotechnical expertise in tropical soils. Attention is drawn to the method of classifying residual soils in grade zones developed during the investigation according to their geotephnical properties. Problems of laboratory investigations of tropical materials are considered.

The value of large scale tests such as trial embankments as a means of assisting in the preparation of a realistic compaction specification for residual soils, and also as a means of testing construction methods in swamp areas are discussed.
Discussion on W. B. Evans
Authors: Arrowsmith E. J. , Morris A. G. , Bradley L.
Published: November 2007

E. J. Arrowsmith, A. G. Morris and L. Bradley (North Western Road Construction Unit) described slips and remedial measures in cuttings at three localities on the M62. With major slips occurring either during construction or after completion of excavation, and with the need rapidly to establish stable slopes, detailed investigations could not be undertaken.

Subsequent observations showed that the slopes had certain features in common. The strata consist of alternating beds of sandstone and shale of the Millstone Grit and beds at the base of the Lower Coal Measures. Bedding dips gently into the cuttings at 6° to 20°. Modes of failure appeared to have been similar in all cases and were interpreted as translational slides on low shear strength materials in a geological setting of partially confined aquifers and potentially high seepage forces.

The authors assumed a general form of wedge failure illustrated in Fig. 1, and presented simplified diagrams and geological cross-sections showing the slope profiles and the suggested limits of rock movement behind the face (Figs. 2, 4 & 5.

Piezometers were installed in boreholes in the north batter of Windy Hill Cutting (Fig. 2) and the recordings from them gave some indication of the response of the several perched water tables to the incidence of rainfall (Fig. 3). They were used to check the effectiveness of the drainage measures in depressing the water-levels below critical values. Low strength materials encountered in the cuttings were probably
clay mylonites
and appeared in each case to have been the
Relations between the acoustic and geotechnical properties of marine sediments
Authors: Buchan Sinclair , McCann David Michael , Smith Denzil Taylor
Published: November 2007

1. Introduction

V
arious theories
have been advanced to relate the attenuation coefficient and the velocity of propagation of compressional waves through a two phase medium, such as a marine sediment, to the elastic moduli, densities and relative concentration of the two constituents. The main difficulty in a natural sediment is the mathematical formulation of the complicated interaction between the particles. In general, the usefulness of most of the developed equations has been restricted by the simplifying assumptions that were used to formulate this interaction.

The relationship between the acoustic and geotechnical properties of a marine sediment is essentially a multivariate problem. In this case, where the understanding of the underlying control of the various geotechnical parameters on the acoustic parameters is incomplete, a large quantity of data must be analysed. Large quantities of apparently unrelated data, or data related in some obscure manner, can often be analysed numerically and in this respect multiple regression analysis is a very powerful method. By this means an effective prediction equation can be developed for the dependent variable in terms of several independent variables. Some of the variables considered maybe redundant and, as such, may be eliminated to concentrate the final computation on the variables ranking highest in their control of the dependent variables. As a result of finding the most significant variables, some idea may be then obtained of the physical relationships between the dependent and independent variables. With this knowledge of the main control parameters, the fundamental relationships between the acoustic and
Some engineering aspects of rock weathering with field examples from Dartmoor and elsewhere
Authors: Fookes P. G. , Dearman W. R. , Franklin J. A.
Published: November 2007

Dear Sir,

We would like to draw the attention of readers to four references on the weathering of Dartmoor granite and erosion surfaces in South Devon. We have just found in a South African publication an interesting paper by Duncan & Dunne (1967) which deals largely with residual soils on the Dartmoor granite. Three papers (Orme 1964; Waters 1964; Brunsden 1964) from the book ‘Dartmoor Essays’ are particularly relevant to understanding the geomorphological and weathering history of the Dartmoor region. We apologize to the authors for not having found these references and included them in our own work.
Water seepage in rock slopes
Authors: Londe Pierre
Published: November 2007

1. Introduction

Rock slopes are loaded by three categories of forces:

(a) weight of the rock mass,

(b) thrust and weight of the dam, and

(c) seepage forces of percolating water.

In order to study the stability of an abutment it is necessary to know all these forces. The seepage forces, however, are often ill-known and sometimes not known at all. So far, engineers use artificial means to confine the seepage field within well defined boundaries. The available means are grouting and drainage.

Thanks to recent developments in rock mechanics, it is now possible to evaluate the respective roles of grouting and drainage on the safety of dam abutments, particularly for arch dams. This is vital as a misunderstanding of these roles could lead to designs that are either needlessly costly, or, worse, give a false impression of safety. A number of findings are valid for rock slopes not supporting a dam.

It is proposed here to develop the latest ideas on this difficult subject. Some of the concepts are still of a speculative nature and numerous field measurements are required to confirm their validity. The few observations made so far do, however, justify the approach.

2. Basic concepts

Consider a rock mass containing a great number of fissures, each of them having a constant width, and assume that the seepage flow is:

(a) steady

(b) laminar

The second condition is valid for rocks with fine fissures and moderate hydraulic gradient. Excluding physico-chemical action, seepage of water can have three
Rapid groundwater flow in fissures in the chalk: an example from south Hampshire
Authors: Atkinson Timothy Christopher , Smith David Ingle
Published: November 2007

Projected road improvements in south Hampshire included plans to dispose of surface drainage into soakaways to be sited near an area of swallow holes in the Chalk. An experiment was undertaken to establish if there was a direct connection between the swallow holes, located near the junction of the Chalk and the Lower Tertiary strata, and major springs used for water supply in the Havant area. As the swallow holes are dry except in periods of storm rainfall a tracer, the fluorescent dye Rhodamine WT, was injected together with a large volume of water into one of the swallow holes. Water samples were collected from the springs at Havant and analysed for Rhodamine WT using a Turner fluorometer. The tracer was found at both sets of springs sampled and the straight line velocity from input point to spring was in excess of 2 km per day. Computations based on the concentration of dye recovered from the springs show that in the event of a tanker spillage within the proposed drainage scheme severe contamination would be expected to occur at the springs. The experiment and the results obtained make it clear that extreme caution should be exercised to avoid contamination of fissure-flow within the Chalk aquifer.
A study of one special type of mudflow in the French Alps
Authors: Azimi Chahrokh , Desvarreux Pierre
Published: November 2007

One of the most dangerous movements in the French Alps is a special type of mudflow sometimes affecting masses of several millions of cubic metres with a high velocity of propagation and large spread if the mudflow is directed by a valley profile.

Forecasting the phenomenon is of great practical importance and for this reason it is necessary to understand the mechanism of formation of this type of mudflow. Generally, these mudflows are observed in larger masses of scree in which there is water circulation. The screes originate from rapidly weathered cliffs of rock. The rocks concerned include sedimentary rocks easily transformed mechanically into silt size particles.

In order to forecast the occurrence of this type of mudflow, the authors have attempted to explain the mechanism of formation of such mudflows in the bed of the River Ravoire (Savoie). One other example is given, for which the above mentioned mechanism seems to be the cause of the mudflows.
Engineering geology of ‘d’ power station Yallourn, Australia
Authors: Beavis Francis Clifford
Published: November 2007

Geological investigations for the ‘D’ extension to the Yallourn Power Station and auxiliary works are described. The investigation included field mapping, boring, and the field and laboratory testing of materials. Brown coal was an important material in the foundations. Under load it behaves as an elasto-plastic substance. On exposure the saturated coal dries out rapidly, with marked shrinkage. Drying of the brown coal resulted in cracking and the opening of joints and bedding separation surfaces.
Development of the groundwater resources of small limestone islands
Authors: Mather John David
Published: November 2007

The lenses of potable groundwater which exist on small limestone islands are a valuable natural resource and their rational development is considered to be of great significance to the inhabitants. Using the assumption that abstracting groundwater from a freshwater lens is equivalent to reducing vertical recharge, an estimate of the sustainable yield of the lens is made. This estimate is refined by taking into account the amount of storage which must remain within the lens so that abstraction can continue during drought periods and also the reduction of the freshwater head and consequent increase in the thickness of the transition zone brought about during pumping. The most effective method of developing the resource depends on the depth to the water table, the thickness of the lens and the permeability and nature of the aquifer. Boreholes are recommended where lenses are thick and shallow infiltration galleries where the available thickness of freshwater is limited.
Stabilization and control of local rock falls and degrading rock slopes
Authors: Fookes Peter George , Sweeney Michael
Published: November 2007

The paper describes design and construction techniques for the stabilization and control of local rockfalls and the products of general degradation from rock slopes. Stabilization measures are discussed and illustrated by a series of idealized cross-sections and examples. Simple nomograms are developed for the design of rockbolt installations and rock-trap ditches.
Geochemistry of groundwaters in British Triassic Sandstones: The Wolverhampton-East Shropshire Area
Authors: Edmunds W. Michael , Morgan-Jones Martin
Published: November 2007

This paper presents a reconnaissance of naturally occurring trace element levels in the Triassic sandstones of the Wolverhampton area, and compares these with levels resulting from contamination.

The three dimensional water quality variation is discussed in terms of major element geochemistry, carbonate equilibria, oxidation-reduction and tritium.

All groundwaters to a depth of at least 100 m below the water table are oxidizing. In the Bunter Pebble Beds and the Upper Mottled sandstones, groundwaters are considerably undersaturated with respect to calcite and dolomite, although in formations above and below, saturation occurs. Post-1953 groundwater occurs only in the uppermost groundwater but some is drawn down under influence of pumping. Low nitrate levels correlate with low tritium. Natural trace metal levels generally have values within the range 1-10 μg/1.
A composite net for the rapid analysis of rock slope stability
Authors: Cruden D. M.
Published: November 2007

The composite net, a combination of a polar equal area net and the great circles of a Schmidt net, simplifies the rapid analysis of rock slope stability by Markland's method. It reduces the number of overlays necessary to one plain transparent sheet and reduces to one the number of rotations of the overlay during the graphical constructions.
Engineering geological investigations for the Kielder Tunnels
Authors: Carter Paul Gilbert , Mills David Audley Corbett
Published: November 2007

The Kielder Tunnels, which commenced driving in summer 1975, will total some 32 km in length. Located between the rivers Tyne and Tees, they will traverse a predominantly gently dipping series of sediments of Carboniferous age, of widely differing lithologies and engineering characteristics, with limited faulting and folding.

This paper describes the geology of the route, and the planning and implementation of the site investigations, which included field survey, boreholes, rock mechanics testing and hydro-geological investigations all designed to determine likely tunnelling conditions.
Engineering geological mapping of the Tyne and Wear conurbation, North-East England
Authors: Dearman W. R. , Money M. S. , Coffey J. R. , Scott P. , Wheeler M.
Published: November 2007

Preparation of an engineering geological map of the Tyne and Wear Metropolitan County, North-East England from available archival, geological and site investigation data has involved appraisal of the general engineering geological conditions of the area. Characteristics of drift-covered areas underlain by Permian magnesian limestones and Carboniferous coal measures are illustrated.

A general classification of engineering geological maps based on purpose, content and scale has been adopted. The principles of mapping in an urban environment are elucidated using large-scale plans to illustrate problems associated with the infilling of a natural valley, old coal workings near the surface, and variable superficial deposits.
Morecambe Bay feasibility study—sub-surface investigations
Authors: Knight Derek John
Published: November 2007

The paper presents a case history of the sub-surface investigations carried out in 1967/68 as part of the Morecambe Bay feasibility study. The planning, scope and methods of execution of the investigations are described, together with the effect of field limitations on the data obtained. The results are summarized and discussed in terms both of the overall stratigraphy of the Bay sub-surface, and also the properties of the principal strata, namely the two main sand layers and the various clays and silts. Particular reference is made to the
in situ
and laboratory permeability testing of these strata, to the obtaining of relatively undisturbed samples of the sands, to the fabric of the clays and silts and to its effect on their shear strength. The application of the work to engineering design is described, its limitations assessed, and conclusions drawn on aspects requiring particular attention in any future sub-surface investigation of the Bay.
Middle East—Review and Bibliography of Geomorphological Contributions
Authors: Cooke R. U. , Goudie A. S. , Doornkamp J. C.
Published: November 2007

It is the purpose of this brief review to provide the engineer with some background information and bibliographic sources to geomorphological studies relating to arid areas, especially the Middle East.

Table 1 summarises some aspects of engineering work in deserts in which geomorphological studies have a role to play, especially with respect to resource appraisals and to the environmental hazards in arid and semi-arid areas.

The analysis of aerial photographs and field survey to map features and deposits of engineering significance can be carried out on a variety of scales (see below). Landforms can be used as indicators of other environmental phenomena of importance to engineering (see Fookes, this vol.). Hazard maps including maps of flooding, unstable sand dunes and salt-weathering processes are frequently produced, and hence the geomorphologist can also help to establish the ways in which undesirable hazards and environmental processes can be ameliorated.

Tricart & Cailleux (1969) and Cooke & Warren (1973) give general treatments of desert landforms and processes and provide extensive multilingual bibliographies. Two important bibliographies are those by Lustig (1968) and by Perrin & Mitchell (1969). Many of the modern techniques of quantitative geomorphological analysis and monitoring that have been applied to deserts have been brought together by Schick, Yaalon & Yair (1974), while desert sediments and sedimentary structures of ephemeral streams have been investigated by Glennie (1970) and Picard & High (1973) respectively. Bagnold’s classic work on wind processes remains an essential introduction to aeolian geomorphology (Bagnold 1941).

Certain specific desert features have
Middle East—A Reappraisal of the Seismicity
Authors: Ambraseys N. N.
Published: November 2007

The Middle East covers a land area of 13.5 million square kilometers, approximately 2.8 times the size of Europe. Its population amounts to more than 185 million as compared to 450 million in Europe, distributed unequally with most living in a mere 6 percent of the total area which is regarded as cultivable and also in the cities. Also, its gross national product per capita is distributed unevenly ranging from about £38 in Ethiopia to £725 in Israel and £2200 in Kuwait with an overall average of only £120 as compared to £760 for Europe.

Until recently the rate of investment in large urban and industrial developments in the Middle East was small and in places insignificant. Consequently there have been essentially no significant economic losses from the large number of damaging earthquakes that occur in this part of the world. Although during the first 70 years of this century earthquakes have taken a toll of 130 000 lives in the Middle East, of which 73 000 perished in 22 earthquakes in Iran and 57 000 in 26 earthquakes in Turkey, damage in economic terms has remained relatively small. The average replacement cost of the 300 000 adobe houses destroyed in Turkey during the period 1900–1966 hardly amounts to a few tens of millions of pounds (Ambraseys 1972). The replacement cost of similar types of construction destroyed in other, less developed parts of the area, is even smaller. For instance, the Silakhor earthquake of 1909 in Iran, in which more
Middle East—Inherent Ground Problems
Authors: Fookes P. G.
Published: November 2007

The arid and extremely arid areas of the Middle East are outlined, and the past and present climatic regimes within these areas considered and related to the existing rock and soil conditions.

A system of classification of the ground into four simple zones based on their desert characteristics and the natural processes operating within the zone is described. The general engineering character of each zone is discussed and particular problems highlighted. Zone I is the mountainous areas, zone II the large gravel fans bounding mountains, zone III the alluvial plains beyond the fans, and zone IV the central base level plains between mountains or adjacent to coasts.

The great majority of desert soils are granular and their engineering behaviour is directly related to their grading characteristics. Flooding is an important hazard in the fans and alluvial plains, while in the base level plains high water tables are of major importance. Ground conditions of significance in deserts, which do not generally occur elsewhere include aggressive salty ground, wind blown sands and silts, and hard and soft duricrusts. These and certain other ground conditions are described.
Middle East—Offshore structures
Authors: Dennis J. A. N.
Published: November 2007

In the last few years, the attention of the public has been increasingly drawn to the subject of offshore structures, particularly as a result of the television and press coverage of the platforms recently installed in the North Sea.

Although North Sea activity has publicised offshore engineering work, structures remote from land have been built for many purposes for some considerable time; however, offshore structures tend to be related to oil operations, and it is to this technology that most offshore structures in the Middle East relate.

In contrast to the severe environment conditions of the North Sea, the conditions of the Middle East are comparatively benign. Fig. 1 illustrates a steel structure being built in conditions typical of the Arabian Gulf. The main area developed to date is the Arabian Gulf, the existing wells and oil related structures generally having been located in relatively shallow waters of less than 60 m depth (
cf.
180 m in the North Sea). New concession areas elsewhere extend to the 1000 m contour and working in these depths will no doubt pose their problems. Concession areas exist off most of the coastline of the Red Sea, parts of the Gulf of Aden, and off the coast of Oman. The latter two areas the relatively unexplored and therefore apart from the more severe weather conditions which are known to exist, difficulties as yet unknown may be met. For example the southern Red Sea areas will pose technical difficulties owing to the coral reefs and
Middle East—Dock and Harbour Problems
Authors: Tarrant L. F. C.
Published: November 2007

In 1971 Dubai was one of seven Trucial State sheikhdoms which formed a loose federation, now known as the United Arab Emirates.

A decade ago Dubai was relatively unknown; today however, with a modern international airport and a 15-berth deep water harbour, it has now become a thriving township and the entrepot capital for the whole of the Gulf Area. Indeed, when the current harbour works are complete, Dubai will have one deep water berth for each 1000 of the indigenous population.

The main harbour developments have been two-fold. Currently a 22-berth harbour extension is being completed, and work on a 74-berth harbour at Jebel Ali has recently begun. In late 1976 however, the main interest centred on the de-watering of the dry dock scheme, the largest dry dock being 525 m × 100 m.

Geology of the area

The stratigraphy within this region of the UAE coast comprises recent carbonate sands, lying upon carbonate sandstone, which in turn overlies interlayered deposits derived from the mountains. Fig. 1 is a schematic section of the regional geology.

Although there are local variations, the general succession encountered during the harbour/dock works in Dubai has been:

On the seabed adjacent to the shore there is a layer of cemented sand, shells and coral up to 1.5 m thick; this bank forms a harder crust layer, a caprock or duricrust, a common phenomena in the Gulf. Generally this hardened layer occurs at the rock surface, but also it can be found in an intermediate
Discussion on ‘The analysis and planning of step drawdown tests’ by L. Clark
Authors: Connorton B. J.
Published: November 2007

May I congratulate Lewis Clark on his paper covering the analysis and planning of step drawdown tests. I think the subject of well performance is due for a ‘shake-up’ and this paper will hopefully initiate some useful scientific discussion in the right direction.

I have two main criticisms to make. The first one is that the author considers only
continuous
step drawdown tests; he makes no mention of conducting discontinuous or
intermittent
step drawdown tests in which each drawdown step is followed by a recovery period of at least equal duration. I have used both types of test and have found the latter provides the more reliable results for the following reasons:

(i) the problem of errors caused by fluctuations in pumping rate within a given step affecting the reliability of data from subsequent steps does not arise;

(ii) the problem of errors caused by extrapolating the time-drawdown trend in order to calculate incremental drawdown does not arise;

(iii) the analysis of transmissivity from the time-drawdown data is straightforward; each drawdown step is treated simply as a short constant rate test, and since errors caused by (i) and (ii) will not exist, the values thus obtained will be more reliable;

(iv) there will be as many recovery steps to analyse as there are drawdown steps, and hence more ‘stabs’ at transmissivity. The recovery ‘
Q
’ values are the same as the preceding drawdown step value; the problem of estimating an averaged or weighted effective ‘
Q
’ for the recovery test does not
An osmotic method for determining rock and aggregate suction characteristics with applications to frost heave studies
Authors: Jones R. H. , Hurt K. G.
Published: November 2007

A recently developed laboratory method in which suction is applied by osmosis has been used to determine the suction/moisture content relationships (suction characteristics) of limestone rock and compacted aggregate specimens. The method, which is described in detail, gave results which were comparable with those from the suction plate and pressure membrane apparatus. It is, however, much superior to these other methods and for the first time permits aggregate suction characteristics to be determined easily.

The suction characteristics have also been used to rank the frost susceptibilities of four limestones. Pore size distributions inferred from the results are consistent with microscope studies.
Engineering geology of small water storage structures in Australian arid regions
Authors: Beavis F. C. , Beavis J . C. , Reade L. M.
Published: November 2007

Embankment stability, inadequate catchment areas, seepage losses and high salinity are the main problems in the successful construction of small water storages in arid and semi-arid regions. It is essential for success that storages be correctly sited, and that the design be suited to the materials available. The investigation for an excavated tank-earth dam system near Broken Hill, Australia, is described as an example.
A review of water well drilling methods
Authors: Cruse K.
Published: November 2007

The paper describes the water well drilling methods currently in use throughout the world and explains the operation, tooling, and application of each system. Notable developments are reviewed and the problems which fostered them are examined. While the main systems of drilling are dealt with, mention is made of the less common methods, some of which may be selected for areas where local conditions warrant their use.

Cable-tool (percussion), rotary and other types of drilling are discussed and also the use of clay-based and organic polymer muds, air-flush, and foam.
Geotechnical, mineralogical and chemical interrelationships in weathering profiles of an overconsolidated clay
Authors: Russell D. J. , Parker A.
Published: November 2007

Weathering of Oxford Clay has been studied in five profiles from different areas. The well-known weathering reaction (pyrite + calcite→gypsum) is the major compositional change. The calcite distribution in vertical profiles is distorted by the introduction of calcite-rich solifluction material above
in situ
weathered clay. Although the correlation of calcite with depth is low, that of calcite with undrained shear strength is high. It is concluded that, although interparticle bond weakening by calcite solution is occurring, the calcite introduced from overlying material may be acting as a cement. Variations in bulk clay mineralogy are small and do not follow consistent patterns. However, the crystallinity of illite in the clay fraction decreases towards the surface; this may reflect the degradation of the crystal structure at the particle margin, where bonding occurs. The weakening of overconsolidated clays is interpreted in terms of bond weakening following oxidation of pyrite; most weathering changes are concentrated near the base of the weathered zone, where this reaction occurs.
An example of the value of infra-red multispectral remote sensing in mapping
Authors: Patoureaux Y.
Published: November 2007

Infra-red multispectral remote sensing can supply data to supplement the information provided by aerial photographs for geological and geomorphological mapping of areas of the earth's surface.

The shades of colours obtained by combining the black and white images of the spectral bands are due partly to differences in the spectral emissivity of the surface, and partly to variations in the thermal properties of the surface materials, themselves dependent upon the nature and state of the surface.

In this paper, the author describes a case study carried out in the vicinity of Carcassonne (Aude, France) where, at several scales, the imagery obtained by aerial survey has helped to define boundaries, for example, between the alluvial terraces and the molassic formations of Lutetien, and between various types of alluvial sediments.
Rapid geomorphological assessments for engineering
Authors: Doornkamp J. C. , Brunsden D. , Jones D. K. C. , Cooke R. U. , Bush P. R.
Published: November 2007

Geomorphological mapping is being used increasingly in engineering projects (especially at the reconnaissance and site-investigation stages) as a rapid, highly cost-effective means of assessing both potential hazards and resources. This is normally achieved through a field mapping programme which is dependent on the availability of aerial photographs, and which involves the correct interpretation of landforms as to their origins, material composition, and associated present-day geomorphological processes. The results of such a survey need to be presented in a form which is of direct use to an engineering geologist and/or engineer. This is best achieved, in most cases, by the production of problem or site-orientated maps derived from the primary geomorphological survey.

The case studies, drawn from several investigations in arid land environments, were made by a small team of (3-5) geomorphologists and geologists, working for short but concentrated periods of time in the field. A search for fine aggregates in Bahrain was closely associated with the identification and mapping of contributing drainage networks and source areas for alluvial fan deposits. Thelocation of trial pits and boreholes at a site in Dubai was rationalised in terms of a reconnaissance map of both landforms and their constituent materials; while at Suez, extrapolation between existing trial pit and borehole sites was made possible from the geomorphological mapping of landform boundaries. Hazards to engineering from flooding (at Suez) and dune migration (in Dubai) were identified, assessed, and mapped on the basis of a knowledge of their place in the overall geomorphological system.
Engineering geological aspects of dock and harbour engineering in Southampton Water
Authors: Barton M. E.
Published: November 2007

A brief survey of the main dock and harbour engineering works in the estuary of Southampton Water is given with particular emphasis on the development of the Port of Southampton. The geology of Southampton Water is reviewed in terms of the lithology of the main formations and the recent geological hisotry. An outline is given of the geotechnical characteristics of the various formations with some quantitative results, although much soil testing is still required. Particular applications of the engineering geology selected for description are those for which detailed studies of the geology contribute significantly to both the design and construction of the engineering works.

Particular engineering works and problems treated include foundations for quay walls and dry docks, control of artesian pore pressures, selection of berthing areas and channels, stability of slopes including underwater slopes, dredging and the characteristics of the reclaimed lands. Those aspects of the geology which are of the most help in respect of these various engineering works and problems are the geological structure and lithological characteristics of the Bracklesham Beds, the nature of the sub-Pleistocene erosion surface, the nature and disposition of the superficial deposits, the geohydrology, and the recent evolutionary history of the estuary.
Development of piping erosion conditions in the Benson area, Arizona, U.S.A.
Authors: Masannat Y. M.
Published: November 2007

Piping is a subsurface form of erosion which involves the removal of subsurface soils in pipe-like erosional channels to a free or escape exit. Although it develops in different types of soils and under a wide range of physico-chemical conditions, piping materials are commonly highly erodible. The present study in the Benson area, Arizona shows that piping commonly develops in alluvial deposits in the vicinity of arroyo-cuts and deeply incised gullies actively trenching in the flood plain deposits. It shows also that soils susceptible to piping usually comprise silts and silty sands with a low clay content, and that they are generally of low dry density, high void ratio, and have collapsing properties.

It was found that overgrazing the area of study in the past and misuse of the land, combined with the climatic conditions of long dry summers with intermittent short rain storms, have contributed to the initiation and development of piping erosion. Gully erosion and badland topography are quite extensive in the area of study due mainly to the collapse of the pipes at an advanced stage of their development.
Itacolumites: the flexible sandstones
Authors: Dusseault M. B.
Published: November 2007

Itacolumites (flexible sandstones) display a bimodal stress-strain behaviour resulting from an unusual inter-digitated grain-to-grain fabric. The sandstone can move freely over a limited arc, then locks, and displays only elastic behaviour. Grain contacts are all open about 5 μm, thereby permitting some free movement. Each quartz grain is interdigitated with its surrounding neighbours, therefore the specimen has appreciable fabric cohesion despite a lack of true mineral cement. Fabric cohesion, as opposed to cementitious cohesion, is strongly stress dependent, and itacolumites can be expected to have highly curvilinear failure criteria.
Experimental assessment of pollutant migration in the unsaturated zone of the Lower Greensand
Authors: Ross C. A. M.
Published: November 2007

In Britain most groundwater resources are held in bedrock aquifers and the unsaturated zone forms an important buffer between landfill disposal sites and the water table.
The processes which control the transfer of (1) persistent organic compounds, (2) inorganic anions and (3) heavy metals, in the unsaturated zone have been evaluated using experimental lysimeters constructed in the Lower Greensand at a site near Uffington, Oxfordshire. Complementary monolith and column experiments were conducted.

Biodegradation is the primary mechanism for the attenuation of the inorganic anions and the organic species, but the migration of heavy metals is limited by interactions with the sediment. Sequential, selective chemical extraction indicates that the stability of the geochemical phases retaining heavy metals controls their rate of movement. Although the processes which regulate the partition of the heavy metals are complex, uptake by sesquioxides and clay minerals are particularly important.
Design of foundations of dams containing soluble rocks and soils
Authors: James A. N. , Kirkpatrick I. M.
Published: November 2007

Four major classes of soluble rocks or soils have been found on dam sites. They are represented by the minerals gypsum, anhydrite, calcium carbonate and halite. Dissolution of these materials can constitute a risk in terms of potential settlements and leakage paths within the foundations of dams. Engineering solutions depend on the solubility and specific rate of solution of the minerals; also upon hydraulic conditions imposed on the foundations.

This paper demonstrates a quantitative basis for the design of safe structures which contain these soluble minerals within their foundations. Site investigation procedures are described so that potential estimates of relevant ground parameters may be obtained and used in engineering design.
Discussion on ‘The littoral sediment budget between Selsey Bill and Gilkicker Point, and its relevance to coast protection works on Hayling Island’ by D. A. Harlow
Authors: Sims P. C.
Published: November 2007

The author is to be congratulated on this interesting paper, the implications of which extend beyond purely local considerations in terms of coastal protection schemes and coastal zone management. It is also encouraging to note that sediment sampling was achieved by diving and ‘visiting the actual environment, so that it can be described in qualitative detail’. This technique has much to commend it. The conclusions on erosion and littoral drift indicate the extreme importance of considering coastal units in which closed cells of sediment movement may occur.

However, the author has omitted to place the model he develops into a wider or longer term context. The coastal area between Selsey Bill and Gilkicker Point is extremely interesting on a number of counts. For example, each harbour entrance possesses double northward recurving sand or shingle spits. The process of recurving is not explained, yet is of obvious relevance to the origin and development of the landforms observed in this coastal unit. A ‘Cuspate type’ foreland exists also at the south-western end of Portsea Island (now largely built over) in addition to Gunner Point on Hayling, indicating a very long history of longshore current driven sediment accumulation in these areas. The strong ebb tidal currents in the harbour entrances, e.g. 5.3 knots (at springs) through Chichester and 4.5 knots at Langstone, probably operate to feed offshore bars such as the West and East Winner banks off Langstone Harbour entrance and the East and West Pole sands off Chichester entrance. This is not