bluuebunny/crossref_metadata_2025 huggingface dataset:
The Pattan (Pakistan) earthquake of 28 December 1974: field observations
Authors: Ambraseys N. , Lensen G. , Moinfar A. , Pennington W.
Published: November 2007

Introduction

In the early evening of 28 December 1974, a magnitude 6.0 (

m
b

USGS) earthquake occurred in a remote and mountainous region of northern Pakistan, resulting in loss of life and damage to property. The Pakistani Army Engineers involved in construction and maintenance of the Kara Korum Highway, a one-to two-lane gravel road along the Indus River valley, quickly established an efficient relief operation. Since the highway was damaged and unusable during most of the relief operation, helicopters were used to carry supplies from Besham, at the end of the usable highway, to Pattan, where a hospital camp was set up.

Two seismic reconnaissance teams visited the affected area: the first arrived from Tarbela Dam on 1 January 1975, and included one of the authors (
Pennington
); the second team, with the other three authors (
Ambraseys, Lensen and Moinfar
) arrived later in January. The following report is based largely on their field studies (

Ambraseys
et al
. 1975

;
Pennington 1975
).

The earliest known earthquakes of the Northwest Frontier Provinces (NWFP)

As early as the 4th century BC, the region north of the Jhelum was reputed for its destructive earthquakes. Historians who accompanied Alexander the Great on his expedition in Swat allude to such events; they briefly state that as a result of earthquakes in this track of country even the beds of rivers are changed. Alexander must have reached Aornos (modern Pir-sar about 20 km from Besham) late in 327 BC (
Stein 1927
,
1929
; Fig. 3).
Stratigraphy and geotechnical properties of weathered lodgement till in Northumberland, England
Authors: Eyles N. , Sladen J. A.
Published: November 2007

Glacial tills in coastal Northumberland deposited by last glaciation (Devensian) ice (c. 25,000 years B.P.) exhibit a reddened post-depositional weathering profile up to 8 m thick, which has previously been misinterpreted as a separate stratigraphic unit, or ‘Upper Boulder Clay’.

Weathering profiles are developed in grey lodgement tills that form an extensive coastal lodgement till plain deposited beneath a wet-based ice sheet. The tills contain intraformational sands, gravels and laminated clays deposited in subglacial meltwater channels and lakes. These sediments have often been partially eroded and incorporated within overlying till resulting in lateral variations in the depth of post-depositional weathering. Sand and gravel lenses, for example, act as drainage layers within the till thereby increasing the depth and degree of weathering and often forming a sharply defined lower boundary to the weathering profile. These features are seen as an apparent tripartite stratigraphy consisting of an upper red till, middle sands and gravels and a lower grey till. Where the depth of the till section is less than between 2 and 3 m only a single reddened weathered till is found.

Weathering takes the form of oxidation followed by leaching of carbonates and is characterized by colour change, increasing content of rotten boulders, and prismatic gleyed jointing. Within the weathering profile four distinct weathering zones can be recognized. Clay and moisture contents increase with degree of weathering giving rise to systematic zonal changes in Atterberg indices and shear strength parameters.

Deep weathering (≏ 8 m) of Devensian till is limited in its geographical distribution to eastern Britain and can be related to the glacial erosion of sulphide-bearing lithologies. The oxidation of disseminated and comminuted sulphides in these Devensian tills is accelerated by the soil cracking that accompanies the development of summer soil moisture deficits under the lower rainfall conditions of eastern Britain.
The synthesis of fracture/strength logs using borehole geophysics: a new geotechnical service
Authors: Halker A. , Kuznir N. J. , Mellor D. W. , Whitworth K. R.
Published: November 2007

In the coal industry, the present energy situation and economic climate have increased the need for rapidly acquired, cost effective, reliable assessment of the strengths of rock which may be encountered in shafts, drifts and access tunnels, this need having hitherto been met by conventional sampling and testing procedures. This paper describes a new technique based on the processing of down-hole geophysical logs to provide a continuous, accurate record of these properties speedily and at relatively low cost.

The basis of the technique is to include a Neutron-Neutron log in the standard logging package and process it with the caliper log either to generate a Hydrogen Index log or simply a caliper compensated Neutron-Neutron log. The derived log is then split into selected lithology-dependent sub-groups and modified according to a predetermined set of calibration constants. These calibration constants have been determined by the authors for the Coal Measures of Staffordshire but can be readily re-determined, if necessary, to suit other coalfields or prospects as required.

The application of the technique has the potential to improve all forms of engineering site investigation where both stability and ‘extractability’ of rock are under consideration, often removing the need to acquire expensive rock core samples, and saving considerable labour costs. In the U.K. coal mining industry fracture logs synthesized using this technique are at present being supplied, so that their value, in the planning and location of shafts and tunnels, in the design of shaft insets and tunnel supports, in the selection of tunnelling machines and forecasting drivage rates and in predicting roof, floor and overburden characteristics may be assessed. It is believed that they will have applications in many other mining or site investigation environments.

The technique described in this paper is the subject of a patent filed by N.C.B. Patents Ltd.
Engineering aspects of weathering of low grade metapelites in an arid climatic zone
Authors: Beavis F. C. , Roberts F. Ivor , Minskaya Larisa
Published: November 2007

Examination of the weathered rock profile of low grade metapelites in arid Australia illustrates changes due to two different weathering environments. The most significant was a period of high rainfall which resulted in some important changes in mineralogy. The second, and present, climatic condition has resulted in halite, gypsum and carbonates in the near surface. Solution has been effective in increasing porosity, which results in a reduction of strength and elasticity. A tentative engineering classification of weathered metapelites is presented.
Discussion on ‘The use of a numerical model in the management of the Chalk aquifer in the Upper Thames Basin’ by E. H. Morel
Authors: Owen M. , Connorton B. J. , Greenfield B. J.
Published: November 2007

M. Owen writes: The area studied by the author is the location of the existing Stage 1 and proposed Stage 2 of the Thames Groundwater Scheme for augmenting river flow at times of severe drought. For an aquifer model to produce reliable forecasts of various management options for developing groundwater resources it must represent real conditions as closely as possible. This requirement is particularly difficult to achieve in an aquifer such as the Chalk which, except in conditions of restricted space and time, must be regarded as heterogeneous. The characteristics of the aquifer in the study area are well demonstrated by field evidence which should be the basis of the model. The representation of this evidence in the model is covered in the following discussion of this paper by Connorton.

In assessing the yield of a major groundwater resource development in relation to the aquifer and not the engineering works, the following criteria should be considered:

Resources—natural and artificial recharge and volume in storage.

Storage removal—regional drawdown in relation to effective saturated depth.

Net gain—the proportion of pumped water which is added to supply.

Connorton later explains how Morel's basic approach to modelling produces unrepresentative distributions of transmissivity and storativity in relation to the operational conditions of the scheme. The over-optimistic predictions that are likely to arise from Morel's model apply particularly to the estimates of the volume in storage and regional drawdown, and therefore lead, under criteria (i) and (ii), to misleadingly high estimates of the quantity
Hydrogeology of the Umm Er Radhuma aquifer, Saudi Arabia, with reference to fossil gradients
Authors: Bakiewicz W. , Milne D. M. , Noori M.
Published: November 2007

Much of North Africa and the Arabian peninsula, lying in the Saharan climate zone, are underlain by huge tabular sandstone and carbonate aquifers, ranging in age from Cambrian to Tertiary. These are often saturated with water of reasonable quality and form very valuable resources in an area often desperately short of water.

The Palaeocene Umm Er Radhuma carbonate aquifer is one such formation which has been the subject of intensive recent investigation. The formation contains groundwater of a reasonable quality, has adequate transmission and storage characteristics and hence considerable potential for future development.

The origin of the water in such aquifers is the subject of continuing controversy. It is not disputed that the water is moving under the influence of regional groundwater gradients but origins of these gradients are the subject of considerable argument. On the one hand, there are those who hold that the presently observed gradients are fossil remnants of conditions created by a much wetter climatic regime prevalent some thousands of years ago. Against this are those who maintain that the gradients, at least in part, reflect a present day system with groundwater discharge in approximate dynamic equilibrium with recharge.

This paper examines the hydrogeology of a typical Middle Eastern formation of the disputed kind, the Umm Er Radhuma aquifer in Saudi Arabia, and, with the aid of analytical and numerical models, attempts to resolve the problem of the origin of the observed groundwater gradients and to discover the extent to which the past must influence present day plans for future development.
The investigation and design of cuttings in stiff Pliocene clays of Lattakia, Syria
Authors: Williams R. E. , Mure R. A.
Published: November 2007

Part of the proposed route for a new highway between Lattakia and Aleppo in northern Syria crosses a sequence of stiff Pliocene clays. Unusually, for stiff clays, the natural water content is considerably above the plastic limit and it is suggested that this is due to the high proportion of smectite (montmorillonite) being strongly cemented by calcium carbonate. Railway cuttings formed at slopes of 1 on 1.5 have suffered a number of failures within 5 years of completion. Cuttings formed at 1 on 2.5 are presently stable, but, being ungrassed, have suffered severe erosion due to high rainfall intensity and lack of maintenance to drainage works. The long term stable natural slope angle varies between 6° and 10°.

The basis for the choice of the design cutting slope of 1 on 3 and associated erosion protection and drainage provisions are outlined.
The periglacial modification of the Lincoln scarp
Authors: Penn S. , Royce C. J. , Evans C. J.
Published: November 2007

This paper describes the effect of periglacial processes on that part of the Lincoln Scarp which is to be crossed by the Lincoln Relief Road. The scarp crest has been extensively modified with the development of small cambered blocks and major gulls parallel to the principal joint direction in the Lincolnshire Limestone. Geophysical investigation has revealed a marked increase in seismic velocity of the basal units of limestone as the degree of alteration decreases down dip (1855 m sec
-1
near the crest and 5000 m sec
-1
300 metres down dip). Electrical conductivity techniques have proved successful in the location of gulls.

Upper Lias clays, which form the scarp, are covered by solifluction deposits and both materials have been affected by processes interpreted as periglacial mass wasting. Relic planar slides associated with the mass wasting have been reactivated during periods of high seepage rates from the Limestone and underlying Northampton Sandstone units. Accurate topographic profiles have been used to determine the nature of complex, shallow rotational slide failures on the upper slopes of the scarp.
The distribution and engineering significance of superficial deposits in the Upper Clydach Valley, South Wales
Authors: Wright M. D.
Published: November 2007

Abernant Colliery, in the South Wales Coalfield, disposes of 300 000 tonnes of washery waste each year onto the floor of the Upper Clydach valley. Rockhead is deeply buried by 20–60 m of superficial deposits which consist of a Lower silty stony clay, Middle bedded silts, sands and clays, and an Upper silty stony clay. The Lower silty stony clay, up to 30 m thick, is of variable composition and is probably a glacial melt-out till. The Middle bedded deposits, thickest in the middle of the valley, were probably laid down immediately after the ice had melted. The Upper silty stony clay, 5 to 15 m thick, may have been largely laid down in the form of valleyside mudflows at the same time as the Middle bedded deposits were being formed, but there is also some evidence of movement of surface layers by solifluction. The presence of water-bearing Middle bedded deposits has caused engineering problems in spoil-heap construction and a slip which occurred in 1981 was in part caused by high artesian pressures in silts and sand in these beds. Many simple, low-gradient valley floor slopes in South Wales conceal highly complex drift successions. While the near-surface material may be strong, it may overlie weak, water-saturated material at a few metres depth.
Engineering geology of the Hammana landslides, Lebanon
Authors: Khawlie M. R. , Hassanain H. I.
Published: November 2007

Studies of the Hammana landslides, in the field and laboratory, enable their geological and engineering parameters to be assessed. The rocks, limestones, marls, sandstones, basalts and unconsolidated cover, possess a high variability in their lithological and geotechnical properties, inducing weakness and directly contributing to the instability of the area.

The types of mass movement correlate either with compact cliff-making rock units, (rock and debris falls and rock slides) or with surficial and other relatively unconsolidated materials, (earth flows and creep). The resulting dominant slopes, being upstanding, convex, concave and rectilinear, show differential stability. Slope stability analysis indicates a more stable “depositional” zone compared to the “erosional” zone.
A geophysical survey of the Crouch/Roach river system in south Essex with special reference to buried channels
Authors: Conway B. W. , McCann D. M. , Sarginson M. , Floyd R. A.
Published: November 2007

A detailed geological and geotechnical survey was carried out in connection with the future development of the South Essex area for a possible third London airport on Maplin Sands. Information on the position of the old buried channels of the Crouch/Roach river system was obtained by carrying out a continuous seismic profiling survey along the present channels of the two rivers. The survey provided information on the depth to the London Clay surface, the thickness and depth of the alluvial deposits, the variation of lithology within these deposits, and the position of some of the buried channels.
Vertical drains used to facilitate road construction for a Medway riverside industrial area
Authors: Finch M. T. N. , Hughes F. H. , Kilner R. A.
Published: November 2007

The paper discusses the ground engineering problems encountered during the construction of a main industrial access road to service a large riparian development on Medway estuarine alluvial deposits. Consideration of the various alternatives to speed consolidation under the road embankment indicated that the vertical band drain system was likely to be the most effective. A planned 12-week contract was completed in 9 weeks at a total saving of 6%.
Stress and slabbing in massive rock
Authors: Chappell B. A. , Williams J. R. , Pollard A. N.
Published: November 2007

Introduction

The measurement of
in situ
stresses is now much easier and more reliable than seven or eight years ago. This is primarily due to improvements, both in the solid state electronics of read out devices and in the epoxy glues used to attach strain gauges to rock. In addition the micro computer now facilitates immediate evaluation of field test data.

This paper discusses the results of a field investigation into the measurement of locked-in stress in a massive sandstone. In addition, the geological factors affecting the behaviour of the sandstone, including changes of loading and geometry due to a road cutting excavation, are examined. Finally, a remedial treatment is proposed to overcome problems which developed after construction and as a consequence of the locked-in stress.

A major road cutting constructed by the Department of Main Roads, New South Wales is located south of Wyong within the Sydney Basin of eastern Australia (Fig. 1). The general profile of the road cutting incorporating the site stratigraphy is shown in Fig. 2.> Thirty-five metres of shale overlie a massive sandstone exposed for 25 m of a known 30-m thickness. Underlying the sandstone is additional shale.

Excavation of the cutting was achieved by ripping in the shale layers and by blasting in the massive Wyong sandstone. The sandstone was presplit prior to blasting. Two years after excavation, and before the road has been opened to public traffic, continual spailing of the 1/4:1 sandstone batter has occurred and become steadily worse. Over a three
Quarrying in the Port Stanley beds
Authors: Rosenbaum M. S.
Published: November 2007

‘The upper quartzitic sandstone (of the Lower Carboniferous Port Stanley Beds) is the most conspicuous rock in the Falkland Islands. It is well seen around Port Stanley in the gaunt, barren ridges whose presence does much to chill the optimism of the stranger arriving at these inhospitable-looking shores.’ (
Baker 1924
).

These sentiments were no doubt echoed by the Task Force as they entered Stanley on 14 June 1982. However, there was little time to reflect on this wilderness as the extent of the war damage became known. The first priority was to reopen the runway at Stanley airfield which had been cratered by bombing. The craters had been temporarily backfilled during the war but now required a more permanent repair with properly graded and durable fill. The second priority was to extend the runway to permit the use of long-distance air transporters and this would require a considerable volume of fill material for pavement foundation construction. Then followed a succession of demands for durable fill including roads, jetties, and concrete aggregate to rehabilitate the Islands and to secure their defence. The urgent requirement for the supply of fill became a primary consideration for the Royal Engineers who were tasked with the location and supply of suitable material.

A number of geologists have passed through Stanley and described the nature of the local geology. The earliest scientific account was presented by Darwin who passed this way 150 years ago (
Darwin 1845
) and systematic mapping has been carried
The occurrence and mitigation of volcanic hazards in Indonesia as exemplified at the Mount Merapi, Mount Kelut and Mount Galunggung volcanoes
Authors: Suryo I. , Clarke M. C. G.
Published: November 2007

Indonesia is one of the most active volcanic areas in the world and has a population of 150 million. Natural disasters affecting large areas and numbers of people are therefore a common occurrence and the authorities have developed strategies to cope with them. On 5 April 1982 Mt Galunggung in W Java suddenly erupted after 64 years and it is still active. From April to June this activity coincided with the rainy season; the volcanic mud and boulder flows (lahars) which were generated ended in late November. Tens of millions of cubic metres of unconsolidated volcanic ejecta, mostly ash and sand size, were deposited around the newly formed crater on the slopes of the volcano and over a wider area. In anticipation of the next rains check dams and other works were planned, as it was feared that as many as 250 000 people might be affected, and further large areas of agricultural land inundated as a result of rain generated lahar. A civil defence system has been initiated, utilizing the experience gained as result of previous similar disasters. The paper summarizes the geological background, and describes the related types of primary and secondary hazards and the attempts being made to mitigate the effects of these hazards.
The application of ground conductivity measurements to geological mapping
Authors: Zalasiewicz J. A. , Mathers S. J. , Cornwell J. D.
Published: November 2007

Non-contacting terrain conductivity meters can greatly assist geological mapping of sedimentary sequences. Case histories from varied geological settings show that clays and clay-rich sediments can be rapidly and effectively distinguished from sands, sandstones and limestones. It is concluded that conductivity methods improve mapping accuracy whilst saving time and effort.
Development and application of a combined soil water-slope stability model
Authors: Anderson M. G. , Howes S.
Published: November 2007

A general one-dimensional soil water infiltration scheme is coupled to an infinite slope stability analysis model to illustrate the potential of exploring the impact of soil suction and parameter variability in stability analysis. The primary data base used for this investigation is published data for the Mid-Levels area of Hong Kong. The model is used to show that current procedures in the estimation of c′ and φ′ derived from strength tests do not perhaps accurately reflect the strength of the residual soils examined. More generally, the desirability of two-dimensional modelling in the context of both soil suction/pore pressure models and stability analysis is discussed, but the parameterization and validation problems of such a scheme are considered to be immense.
Engineering geology related to quarrying at Port Stanley, Falkland Islands
Authors: Rosenbaum M. S.
Published: November 2007

The engineering geological characteristics affecting quarrying in the area around Stanley in the Falkland Islands are described. The hardness of the highly cemented sandstone bedrock, the overburden lithologies of clay, sand and peat, and the relatively high water table are shown to be major controlling factors in the excavation of rock aggregate.
Dissolved iron in chalk groundwaters from Norfolk, England
Authors: Lin-Hua Song , Atkinson T. C.
Published: November 2007

The chemical principles governing iron dissolution in groundwaters are reviewed. In the upper River Bure catchment in Norfolk the Chalk aquifer is covered by sand and gravel drift aquifers and a leaky till aquiclude. Iron contents of groundwaters are several mgl
−1
beneath till, but less beneath valleys where the till is not present. The iron contents and redox potentials of chalk waters are related to groundwater flow in two separate circulation cells. In the larger cell, chalk beneath the higher parts of the catchment receives recharge which has high Fe and low Eh due to oxidation of pyrite in the drift formations. Iron contents in the chalk groundwater decrease with depth and towards discharge areas, probably reflecting precipitation of iron carbonate. Iron content decreases further where ground-waters discharge upwards beneath the Bure valley and mix with waters of the second circulation cell which occurs where the till has been removed by erosion. Oxygenated, iron-poor waters recharge the chalk beneath the upper parts of the valley sides and discharge through the valley floor. Mixing between waters in the two cells may cause precipitation of iron oxides. Similar flow patterns have been demonstrated elsewhere in East Anglia and it is likely that iron contents will generally be lowest where active groundwater circulation occurs beneath till-free valley floors.
Introduction
Authors: Puri S. , Puri K.
Published: November 2007

‘Exotic uses of aquifers’ was the unusual title of a Hydrogeology Group meeting held on 9th October 1984; the title was inspired by a scientific paper written by Kazmann in 1979.

The majority of U.K. hydrogeologists are concerned with fresh groundwater, usually for potable supply. Increasingly, however, they are being called upon to take part in a wider scientific debate, for example, that concerned with contaminants arising from disposal of environmentally unacceptable waste. Viewed from an alternative point of view, a ‘disposal’ site is a ‘repository’. From such alternative standpoints it is easy to see how the subsurface can be used for storage of gas, petroleum or other fluids. Similarly, pre-existing fluids in the subsurface space can be utilized by heat pumps or even for hot spas and health resorts.

The purpose of the meeting, therefore, was to compare techniques used by non-hydrogeologists who also deal with the subsurface space. To fulfil these objectives the meeting was organized in three parts: an Overview, followed by a consideration of Physical Processes and, finally, Case Histories.

In their Overview, Edworthy & Puri deal only with porous medium (granular) aquifers, arguing that fractured rocks, or those where caverns can be constructed, require a separate extensive consideration. They consider ‘exotic’ uses to be covered under four headings, stating that an exotic use is undertaken in order to obtain some form of social benefit:

Fluid Storage and Waste Disposal

Energy Conservation

In situ
Leaching of Minerals

Groundwater Quality Management.

They show that to achieve benefits
Mathematical modelling of radionuclide migration in groundwater
Authors: Herbert A. W. , Hodgkinson D. P. , Lever D. A. , Rae J. , Robinson P. C.
Published: November 2007

This paper reviews recent work on the development of mathematical models for the transport of radionuclides in flowing groundwater. These models have an important role to play in assessing the long-term safety of radioactive waste burial, and in the planning and interpretation of associated experiments.

Firstly, general multi-dimensional numerical models for the flow of water and the transport of dissolved radionuclides through permeable media are described. Their use in assessing the importance of possible transport pathways is illustrated by examples of flow in rocks with high permeability fracture zones.

Secondly, recent advances in the description of flow and transport through fractured rock masses are considered. The results of field experiments are used to examine the characteristics of single fractures such as transmissivity, the proportion taking flow and the diffusion of ions into the surrounding rock. In addition, network models are used to examine the connectivity, flow and hydrodynamic dispersion through fracture systems and to assess how well transport can be modelled by an equivalent permeable medium model. The fracture systems are defined by probability distributions for the orientations, lengths and hydraulic apertures of fractures together with information about the number of fractures per unit volume. It is found that, providing the region size is much bigger than the mean fracture length, the permeability is constant, but that hydrodynamic dispersion is not adequately modelled by a diffusion-like term.
Discussion on ‘The location of the Stour buried tunnel-valley using geophysical techniques’ by R. D. Barker & D. Harker
Authors: Cornwell J. D.
Published: November 2007

In their use of geophysical methods to supplement sparse borehole data for locating a buried tunnel-valley in the Chalk of East Anglia, the authors include an interesting application of detailed gravity surveys. The thick boulder clay in-fill of the narrow valley gives rise to small Bouguer anomaly highs and a density contrast is derived of +0.26 t/m
3
between this material and the Chalk. The sand and gravel in-fill is concluded to have a negligible density contrast. The authors then interpret gravity profiles over parts of the tunnel-valley with both types of in-fill, by adopting an ‘effective density contrast’ weighted according to the proportion of boulder clay present in adjacent boreholes.

This approach to the gravity modelling of the overall form of an anomalous multi-component body is, however, only valid if the dimensions of the individual components of the body are significantly smaller, perhaps by an order of magnitude, than that of the body itself. On the evidence of Fig. 2 in the example described, the ‘effective density contrast’ appears not to be valid for the whole tunnel-valley, as there is only one horizon of boulder clay and, at depth in the tunnel-valley, one horizon of sand and gravel in both the Cavendish and Glemsford boreholes. If the sand and gravel has no density contrast with the Chalk then it is surely not possible to derive a model from the gravity data for the bottom part of the valley, below the boulder clay. The adoption of an incorrect density contrast additionally
Electrical conductivity and saline concentrations in arid land groundwaters
Authors: Doornkamp J. C. , Ibrahim Hani A. M.
Published: November 2007

Measurements in Bahrain (

Doornkamp
et al
1980

), have shown a strong linear relationship between electrical conductivity and the ionic concentrations of sulphates and chlorides in groundwaters. Indeed, the relationship proved so strong as to imply that electrical conductivity could be used as a surrogate for sulphates and chlorides, and that the two latter could be estimated from the former in field reconnaisance surveys or even site investigations.

This is of critical importance to the construction industry, and to agriculture, in hot arid lands. Concrete is known to deteriorate rapidly in the presence of saline groundwater (
Fookes & Collis 1975
,
1976
;

Cooke
et al
1982

), and any quick estimate of the sulphate and chloride levels is of practical value. Field measurements of electrical conductivity can be made rapidly using a portable electrical conductivity meter, while the laboratory analyses of sulphates and chlorides need care and introduce time delays, particularly for the construction industry, as well as additional costs.

What is not known is whether the results obtained in Bahrain provide a universally applicable relationship. Do the regression equations obtained in Bahrain hold good for all hot arid lands? If so, can they be used as a basis for estimating sulphate and chloride concentrations from simple electrical conductivity measurements without the need to resort to laboratory tests? Some standard texts (e.g.
Davis & de Wiest 1966
) suggest this could be so.

To test these questions two further analyses have been carried out. The first is for data collected by the Egyptian Groundwater
Production of borehole logs using a microcomputer
Authors: Chaplow R.
Published: November 2007

A software package has been developed and implemented on a BBC microcomputer system which allows borehole data to be entered into disc files and full borehole logs, including both graphical and textual components, to be prepared automatically from the stored data. The operator can select the required format and scale from a menu of standard options or can set up any required special layout. Any required scale can be selected and log headings may be printed in either the English or French language. Once a set of data has been entered into a disc file, the information can be replotted at will to any required format and scale. Thus, after having prepared a detailed log at say 1:50 scale, the same data can be replotted as a summary log at, for example, 1:200 for direct inclusion in an interpretative drawing and as a simplified log at 1:100 scale.

Detailed borehole logs can be prepared using the computer system with man-hour inputs of around 300f those required to prepare similar logs manually. Overall cost savings increase dramatically if there is a need to replot the same data to produce summary or simplified logs as would be required for the preparation of interpretative reports and drawings.
Soil pipes and slope stability in Hong Kong
Authors: Brand E. W. , Dale M. J. , Nash J. M.
Published: November 2007

Introduction

A recent paper by
Pierson (1983)
provided sound evidence of the contribution of soil pipes to landslides. Whereas the existence of pipes has been documented in a good number of publications, their importance in the context of slope stability has not generally been appreciated. Attention is now focusing on pipes in Hong Kong as a major contributory factor to frequent landsliding.

Pipes in Hong Kong

The hilly terrain of Hong Kong is prone to landslides brought about by the heavy seasonal rainfall (
Lumb 1975
;
Brand 1984
,
1985
). The granites and volcanic rocks are weathered to considerable depths, the surface residual soil often being overlain by a mantle of colluvium. Until recently, it was not realized that the existence of pipes was an important factor in the overall stability of some of Hong Kong's hillsides, and that they have undoubtedly been the main cause of some of the failures that have occurred in Hong Kong cut slopes (

Premchitt
et al
., 1985

).

The pipes in the residual soils and colluvium of Hong Kong cover the range of types described in the Paper and discussed previously by
Crouch (1976)
and
Jones (1981)
. They vary considerably in diameter, in length and in depth in the soil profile. In some cases, they are suspected of comprising anastomosing networks which cover large areas (
Nash & Dale 1983
).

Pipes in Hong Kong are most commonly exposed in shallow excavations in A and B soil horizons, as described by
Crouch (1976)
. These are most commonly attributed to
Discussion on ‘The influence of ground and groundwater geochemistry on construction in the Middle East’ by P. G. Fookes, W. J. French & S. M. M. Rice
Authors: Warren C. D.
Published: November 2007

C. D. W
arren
writes: The authors are to be congratulated on several interesting observations but, with respect to the likely cause of settlement of the Dubai dry dock pier D caissons, it is important to note that their fig. 12 gives a totally simplistic and possibly distorted view of the actual geological conditions that exist beneath the settling caissons, as indicated by boreholes. It must be stated that at the levels which suffered settlement, i.e. -17mOD and to a lesser extent -21.5 mOD, the boreholes did encounter thin horizons of generally uncemented gypsiferous sandy silts, up to 1 m thick, within the more competent calcarenite rock, made up of alternating units of miliolite sandstone and bioclastic limestone (Warren 1985). Therefore a mechanical process should not be totally discounted on the information presently available, particularly in view of the fact that channelled water flow and ‘piping’ of similar material was noted during mapping the numerous excavations extending beneath the dock floor, see Fig. 1.

The uncemented fine sandy silts, present at the boundary between the bioclastic limestone and overlying miliolite sandstone, displayed a marked
variation in thickness, degree of cementation and gypsum content over short lateral distances, believed to reflect their former environment of deposition and subsequent mode of formation. Such facies variations, together with occurance of a saline groundwater intrusion beneath the dock itself, could partly explain the difference in both rock and water chemistries quoted by the author as supporting evidence for gypsum solution. However, it is to be
Site investigation practice
Authors: Hawkins A. B.
Published: November 2007

Site investigation is at the heart of engineering geology. Consequently, when the subject of the Guildford Conference was known it was not surprising that a large number of papers was offered. This interest warranted a change in the usual format of the Regional Meetings of the Group, and allowed the production of pre-prints of the Conference papers and the introduction of each session by a lead speaker. The traditional field day was also modified as a number of the leading site investigation firms had kindly offered to demonstrate the performance of in situ field testing. Fortunately, the layout of the University of Surrey campus allowed these field demonstrations to take place close to the Conference Exhibition, and hence half of the Tuesday was devoted to watching these tests and inspecting the very large display of goods and techniques in the Trade Exhibition. A number of interesting field visits were arranged for the rest of the day.

Nearly 240 people registered for the Conference, making it the largest Regional Meeting for over a decade. The forty-five papers accepted were off-set lithoed and Volume I was issued several weeks before the Conference.

The papers submitted by the lead speakers after the Conference were combined with the written discussion contributions to form Volume II of the Conference Proceedings. In view of the interest shown, the Geological Society agreed to have both volumes printed as a Special Publication of the Engineering Group.

As the full papers will not appear in the Quarterly Journal of
Groundwater management problems in abandoned coal-mined aquifers: a case study of the Forest of Dean, England
Authors: Aldous P. J. , Smart P. L. , Black J. A.
Published: November 2007

An examination has been made of groundwater related problems experienced in the Forest of Dean since abandonment of the major collieries in 1965. Careful planning prior to abandonment of collieries can reduce the number of poor quality discharges, and so substantially limit surface water pollution. Small-scale mining activity continuing after major colleries have been abandoned can have a serious hydrogeological effect by removal of
in situ
coal from drainage barriers designed to promote free drainage of the mines. In association with the deterioration of lined river channels which retard surface water infiltration, this disruption of subsurface can result in a drainage significant loss of summer base-flow from surface rivers.

Two case histories show that safe disposal of wastes to voids in mined Coal Measures aquifers is possible. Prediction of the hydrogeological behaviour of the mined aquifer is, however, difficult because of the possibility of unrecorded workings, random collapse and associated ponding, and uncertainty over the hydrological behaviour of the coal barriers. Direct investigation of the groundwater flow regime using boreholes and water tracing techniques is recommended.
Engineering properties and behaviours of stabilized compressed tropical soils
Authors: Ola S. A.
Published: November 2007

This paper summarizes the work done so far on stabilized compressed tropical soils as a replacement for sandcrete blocks. The study shows that the effects of compaction far outweight the effect of cement content in a compressed block; however, compaction pressures greater than 8 MN/m
2
will increase neither the tensile strength nor the compressive strength significantly. The ratio √length × breadth/thickness is a very important ratio for compressed blocks, and the crushing strength increases with the increase of this ratio for constant compaction pressure and constant cement content. Thus the cinva-ram press will give the highest strength whilst the tek-block will give the lowest strength. The work recommends a minimum wet (soaked) strength of 1.4 MN/m
2
for soilcrete blocks, and 2.8 MN/m
2
for dry strength to be used for building. For the most economic benefit, a compactive pressure of 4–8 MN/m
2
and a cement content of 5–9% are recommended for a commercial soilcrete venture.
The origin of structuration of the Grande-Baleine marine sediments, Québec, Canada
Authors: Locat J. , Lefebvre G.
Published: November 2007

Sediments of the Grande-Baleine River were deposited in a brackish sea about 7000 years ago; the salinity was not less than 8 g/1. This fine-grained sediment was uplifted more than 150 m above sea level. The soil is extremely sensitive (S
t
> 200 as measured by the fall cone), the liquidity index is often above 2. In the odeometer, this sediment is highly compressible and presents an overconsolidation ratio greater than 2 and this with signs of little erosion. Research work has yielded a behavioural model that includes different processes such as early cementation during or soon after deposition and leaching to the actual porewater salinity of 0.5 g/1. Both processes have resulted in a sediment with abnormally high water content (with respect to effective stress) and a high liquidity index, due in part to leaching. Field and laboratory work demonstrate that for this soil, processes responsible for its structuration are leaching and cementation (or anything that has prevented the soil from consolidating completely). No evidence could be found that would suggest the action of delayed consolidation. Today this soil appears geologically normally consolidated (i.e. there is no erosion or surcharge), mechanically overconsolidated (O.C.R. >2), and physico-chemically underconsolidated (abnormally high water content).
The use of geophysical surveying methods in the detection of natural cavities and mineshafts
Authors: McCann D. M. , Jackson P. D. , Culshaw M. G.
Published: November 2007

The use of geophysical methods for the location of cavities and mineshafts is reviewed in relation to engineering problems at the site investigation stage. Their success is limited by the resolution and penetration achieved by the particular method applied in a given situation. It is shown that no one single geophysical method will provide the answer to all the problems associated with cavity location but considerable improvement can be achieved by the application of several methods to a given problem.

It is suggested that for most standard geophysical methods it is possible to detect a cavity whose depth of burial is less than twice its effective diameter. The concept of effective diameter is shown to be of considerable importance since the presence of the cavity or mineshaft does affect the physical properties of the surrounding rock mass and, hence, gives rise to a far larger anomalous zone than that produced by the cavity on its own.
G. West replies
Authors: West G.
Published: November 2007

I would like to thank Mr Gerrard for his interest in the Technical Note, ‘An observation on Mohs' Scale of Hardness’, and his discussion of it. He is also thanked for the reference to the work of Young & Millman (reported by
Duncan 1969
) on the same topic. Mr Gerrard is undoubtedly correct in supposing that much of the variation in the abrasiveness test results for individual minerals shown in fig. 2 of the paper is due to anistropy of the specimens, probably arising from all the factors he mentions together with small variations in composition of the mineral.

Professor D. M. Cruden of the University of Alberta (pers. comm. 1986) is also thanked for drawing attention to the work of
Tabor (1954)
who showed that each standard mineral on Mohs' scale is approximately 60% harder than the preceding one, and that Mohs may have tried to obtain ‘equality of the intervals’ when he selected the minerals for his scale.
The design and construction of a grade-separated interchange over soft alluvial and estuarine soils, A38 trunk road, Plymouth
Authors: Harris J.
Published: November 2007

This paper presents a case history of the ground investigation, design, construction and performance of a grade-separated interchange on the A38 trunk road at Plymouth, which was built over a low lying, marshy site, underlain by a complex distribution of soft organic silt and clay and landfill.

The geology of the site and the integration of the geotechnical study into the design process in an interactive manner are described. Earth and rockfill embankments of up to 10 m in height were built in stages, using vertical band drains to accelerate the rate of consolidation of the soft foundation soils. Soft ground beneath one of the bridge sites was pre-loaded by a temporary surcharge of fill, before installing the pile foundations. The ground treatment and the earthworks are described, the use of extensive instrumentation to control construction is discussed and the results of monitoring are presented.

The location, design and construction of the structural elements of the interchange, including two single span bridges, three culverts and a pedestrian underpass, were severely constrained by the geological conditions at the site and are described in the paper. The contribution which careful geotechnical study integrated with ground treatment and instrumentation can make to design and construction of such schemes is discussed.
Engineering geological aspects of the Edgecumbe, New Zealand earthquake of 2 March 1987
Authors: Franks C. A. M.
Published: November 2007

A sequence of small earthquakes in the Bay of Plenty culminated on 2 March 1987 in a Richter magnitude (
M

L

) 6.3 event under the Rangitaiki Plains, which produced felt intensities of up to MMX in the epicentral area. However, the soft saturated sediments of the Rangitaiki plains suffered permanent inelastic deformation leading to structural and ground damage consistent with felt intensities of up to MMXI in the town of Edgecumbe. This earthquake, which resulted in ground surface rupture, provides a significant case history. Records of strong ground motion some 15 km from the epicentre show a similarity to the 1940 El Centro N-S record. Other ground damage included widespread liquefaction phenomena such as sand ‘boils’, lateral spreading of embankments, low angle slope failures, and minor slope and cutting failures across the plains and in the surrounding hills. The relationship between the sedimentary regime, topography, underlying geology and resulting ground damage in the region is discussed. The seismic responses of the soils and rock are shown to be generally consistent with their geotechnical characteristics and the magnitude of the event.
Durability problems associated with clinker ash/cement bricks: Windhoek, Namibia
Authors: Davies G. , Oberholster R. E.
Published: November 2007

Problems of pop-outs and associated iron staining on unplastered clinker ash/cement brick walls in Windhoek after a particularly wet rainy season were investigated. The problems were found to be due to sulphurous nodules present in the bricks. The nodules were the result of the burning of pyritic fragments present in the coal used as fuel for the local power station, which produced the clinker ash used in making the bricks. The nodules before expansion were found to be distinctly zoned, with centres consisting of free sulphur, amorphous to poorly crystalline iron sulphides (pyrite, marcasite and pyrrhotite) and unburned carbonaceous material, enveloped by a red-coloured zone of iron oxides which was in many cases surrounded by a silicate zone. In the presence of water the iron sulphides and sulphur became oxidized to iron sulphates and sulphuric acid. A resultant large increase in volume caused the pop-outs. The sulphuric acid dissolved iron oxides in the adjacent zone, enveloping the centre zone which, when free water was available, resulted in severe iron staining in the area around the pop-out.
Petrographical comparison of old and new control stones for the accelerated polishing test
Authors: West G. , Sibbick R. G.
Published: November 2007

A petrographical examination of the old and new control stones used for the accelerated polishing test shows that whilst the old control stone is an alkali granite, the new control stone is a dolerite. In spite of this difference the two stones give the same ‘polished stone value’, and it is suggested that this is because they have a similar mean hardness as calculated from their observed mineralogical composition.