bluuebunny/crossref_metadata_2025 huggingface dataset:
Recent Techniques in Geophysics with Special Applications to Engineering Geology
Authors: Caldwell R. A.
Published: April 2008

Abstract and Introduction

Geophysical field measurements are now more frequently employed to gain information about the ground conditions, so that construction projects can be economically and safely designed. This is especially the case for offshore structures and nuclear power plants or where the ground conditions are poor.

Large scale structures require aseismic design and this area of application has been greatly improved, as we can accurately analyse the dynamic properties of the ground. Instruments are also available to monitor the ground behaviour during and after construction so that the new stress conditions can be evaluated.

The fields which have been improved recently are: the seismic reflection technique for shallow exploration, the measurement of shear wave velocity to determine dynamic modulus, borehole measurement of all types and most recently radar to give a continuous high resolution section of the near surface. All these techniques have been improved by new technology enhancing the display and plotting capability and
S/N
ratio, as well as continued development of the theoretical problem.
Marine Site Investigations and BS 5930
Authors: Carter P. G. , Pirie R. M. , Sneddon M.
Published: April 2008

Marine site investigations are reviewed briefly, in terms of suitable drilling platforms and craft for various conditions, requirements for permissions and service locations, marine ground investigation methods and marine survey methods including geophysical profiling.

The wide range of marine site investigation methods is illustrated and the appreciable differences from land site investigation methods are noted. It is suggested that BS 5930 does not give sufficient guidance on marine site investigations and that this situation should be rectified.
A Rational Approach to Consolidated Undrained Triaxial Testing
Authors: Coatsworth A. M.
Published: April 2008

Because of sampling disturbance the results of unconsolidated undrained triaxial tests often show a considerable scatter and seriously underestimate the undrained strength of a natural soil.

Therefore, consolidated undrained triaxial testing is sometimes used, the fundamentally based methods being Bjerrum's, in which specimens are anisotropically consolidated to the field effective stresses, and the SHANSEP method, in which specimens are consolidated to much higher stresses, allowed to swell if the soil is overconsolidated
in situ
, and the results then normalised. The relative merits of these two approaches depend on the type of soil.

In commercial practice, however, most consolidated undrained triaxial testing is carried out on a purely empirical basis, in part because both the Bjerrum and SHANSEP methods require anisotropic consolidation procedures which are not commonly available. Approximations to actual soil behaviour can be used to devise a Modified SHANSEP method, which utilises conventional isotropic consolidation.

Two site investigations are cited as examples of the use of the method, and in both cases the derived undrained strengths were higher than those from unconsolidated undrained testing.
Simplified Descriptive Scheme and Classification System for the Logging of Cut Slope Faces
Authors: Gamon T. I. , Finn R. P.
Published: April 2008

A simplified descriptive scheme and classification system is currently being used for the systematic logging of cut slopes for a 22 ha site formation project in weathered granitic rocks in Hong Kong.

The site formation comprises the removal of some 1.5 million m
3
of soft granitic soil and 3.5 million m
3
of sound rock, and the formation of approximately 60,000 m
2
of slope face. The cut slope faces are logged as they are exposed, and the slope protection and stabilisation works designed and installed as the site is lowered.

A simplified descriptive scheme was considered essential to reduce the time for logging and eliminate the need for specialist logging personnel.

Existing descriptive schemes were compared and the most useful, compatible indices selected. Additional indices from other authors were added where appropriate. This descriptive scheme was simplified after the site investigation stage of the works and the resultant scheme checked against the faces exposed during the excavation of 300,000 m
3
of weathered granite as part of the advanced works.

The finalised simplified scheme was documented as a manual, which has been used on site to standardise the descriptions, abbreviations and presentation. Once logged, the exposed weathered profile is classified into zones, and the distribution of the zones compared with a number of standard profiles to rapidly assess the stability of the ‘soil’ slopes.

To date, 40,000 m
2
of slope face have been logged at a scale of 1:100, and appropriate slope protection and stabilisation works designed and installed.
The Choice of Test Methods in Site Investigations
Authors: Marsland A.
Published: April 2008

The appropriate choice of sampling methods, laboratory tests and
in situ
tests depends upon the type of structure or earthwork being
considered, the nature of the ground influenced by the construction and the required
accuracy of the prediction. To obtain optimum results requires considerable experience
of the design requirements and potential construction problems as well as the test
methods and their range of application. Some methods are particularly useful for
obtaining continuous profiles and giving a rough indication of the engineering
properties while others are designed to provide more basic soil parameters. The
results obtained may be sensitive to changes in equipment details, test procedures and
methods of interpretation.

When empirical relationships are invoked, care is necessary to ensure that identical
equipment and procedures have been used and that the correlations have been obtained in
similar soils. The degree to which the volumes of soil tested are representative of the
soil in the mass is important. Factors such as the orientation of the maximum stresses
applied during the tests relative to the directions of the macro fabric features, the
degree of stress anisotropy, the directions of the stresses applied to the structure
and the effects of disturbance during sampling and insertion of
in situ
devices need careful consideration.

Test data from the most appropriate
in situ
and laboratory tests
should be integrated with soil fabric studies in order to produce the best overall
assessments.
An Appraisal of Soil Index Tests
Authors: Medhat F. , Whyte I. L.
Published: April 2008

The development of liquid and plastic limit tests is reviewed. It is confirmed that the fall cone method is more reliable and reproducible than the Casagrande method for the liquid limit, and this test is adequate for index purposes. The plastic limit has remained effectively unchanged for sixty years and there is no accepted alternative procedure. The Atterberg/Terzaghi rolling bead method is not of adequate reliability and reproducibility. It is proposed that the remoulded shear strength of a fine soil provides a rational basis for index tests. Extrusion and cones have been used to investigate simple methods and it is concluded that both approaches have potential, with the cone test probably being the simpler and more economical approach. Four clay soils were used in the investigation, and it is recommended that a wider range of plastic soils be tested to confirm or otherwise the validity of this approach to index testing.
An Example of Rotary Core Drilling in Soils
Authors: Scarrow J. A. , Gosling R. C.
Published: April 2008

pAs part of a large geotechnical investigation carried out in the Middle East over 50 boreholes, totalling some 2000 m, were put down by rotary core drilling in soils. The site was located on an alluvial flood plain and, in keeping with their origin, the soils encountered were very variable with clays, silts, sands and to a lesser extent gravels being present.

This paper describes the rotary core drilling equipment used, which included both conventional drilling on rods and wire-line systems, together with the synthetic polymer flushing medium. This method of total volume sampling together with the quality of the cores, their description and photography are discussed briefly. The method ensured realistic gradings, with all fractions of the material being present, and allowed laboratory determinations of natural density and moisture content on rotary cores of granular materials leading to direct assessments of relative density.
Investigation of Ground Heave at ICI Mond Division, Castner-Kellner Works, Runcorn
Authors: Sibley M. H. , Vadgama N. J.
Published: April 2008

A serious crack was first noticed in the ground bearing floor slab of K-Unit Plant in September 1977, nine years after its construction. By 1981 measurements shoved the floor near the crack to have risen 80 mm above design level. Significant upward movement of structural columns and beams was also recorded. These movements were beginning to disrupt the working of the plant and in 1981 it was decided to investigate the phenomenon.

A desk study showed that furnaces once stood on the site, with caustic soda storage tanks nearby. A heavy wall once occupied the approximate line of the present crack. Subsoil contamination by alkali solutions was also suspected.

Ground conditions were investigated using light cable percussion boreholes. The nature of the problem, however, called for techniques not covered by BS5930. A magnetic probe extensometer was installed at the point of maximum heave, and in the laboratory soil specimens were subjected to swelling tests using special apparatus and techniques.Chemical tests and X-Ray analyses were also made.

Five possible mechanisms of swelling were investigated, and it was shown that the heave resulted from a slow alkali-clay reaction. Predictions of future movements were made and these allowed the remedial work to be planned.
The Quality of U100 Sampling
Authors: Whyte I. L.
Published: April 2008

The origins and development of the U100 (U4) thick-walled open-drive sampler are reviewed. The requirements of CP 2001 and BS 5930 are examined in relation to sample quality, and these are shown to be too favourable. Causes of sample disturbance are considered, particularly those due to volume changes, and shown to depend on moisture content, plasticity and particle size distribution. Quality classes possible with conventional U100 samples are suggested, and Classes 3 or 4 are to be generally expected. Class 1 samples are improbable. It is recommended that a general purpose sampler such as the U100 should have a maximum inside clearance of 1% and not ‘about 1%’ as recommended in BS 5930.
The ‘Valvate’ System Related to Percussive Boring and Sampling Techniques
Authors: Vallally C. O.
Published: April 2008

Accurate borehole records and water tables are the two most influential factors in any ground investigation survey. These form the basis of any early conclusions and final design. It therefore follows that the samples taken, disturbed and undisturbed, are representative of the strata encountered.

An innovation, the ‘Valvate System’, has been developed recently. The main feature of geotechnical importance is a one way control flow representing the soil profile through which the boring or sampling tool penetrates.

In a boring operation through cohesive or granular soils, the system allows a better visual examination and assessment, by the operator on site, of the soil stratum where lenses of silt, sand, drainage paths/response zones may be present. These discontinuities can be noted on site accurately and correlated later by examination of samples in the laboratory.

With the present method of percussive boring, especially in soft sensitive soils, the structure is destroyed by ineffective strokes of the claycutter causing re-gurgitation and distorting any geological sequence.

The ‘Valvate System’ has been applied to boring and sampling tools; this paper describes the equipment and various applications, which have undergone trials conducted by contractors and local authorities.

VALVATE: Having Valves—Oxford Dictionary Definition.
State of Weathering: The Search for a Rational Approach
Authors: Dearman W. R.
Published: April 2008

In BS 5930:1981 both the state of weathering of rock
material and a scale of weathering grades for the rock mass
are included in a Code for the first time. The schemes
proposed are largely derivative from those proposed by
Working Parties of the Engineering Group, which in turn
benefited from earlier studies in Hong Kong and Australia.

The descriptive terms used for rock material: fresh,
discoloured, decomposed, disintegrated, are defined, and the
stages of weathering subdivided using qualifying terms, for
example 'partially discoloured'. These descriptive qualifying
terms may be quantified if necessary, but no indication is
given as to how this should be done.

Following recent Australian practice, the scale of
weathering grades of the rock mass is described in the terms
applied to the rock material. Except in the case of Grade 1,
Fresh, discontinuities and other defects of the rock mass are
not mentioned. This implies, and it needs emphasizing, that
the descriptive terms for the degree of weathering should
provide a reliable indication of the effects of weathering on
the engineering properties or engineering behaviour of the
rock mass. The material and the defects, such as
discontinuities in the rock mass, therefore need to be
described separately.

A descriptive scheme is proposed for the simple definition
of weathering classes of rock material, and application of
these classes to the description of the rock mass is also
considered.

The effect of scale, particularly the spacing of discontinuities
and thickness of highly weathered zones, is
important in assessing the engineering properties of the rock
mass. This can be dealt with effectively in the descriptive
logging of drill core and rock exposures.
Planning and geology
Authors: McDonic G. F.
Published: April 2008

Most of those engaged in town and country planning are aware of the importance of geology regarding their subject. Indeed there are many geologists now engaged in the planning service.

There are two areas, in particular, where geological skills will be required on an increasing scale in the future.
These are in mineral planning and landfill and restoration on the one hand, and countryside planning on the other.

Land use planning is a political process and has as its basis the positive role of development plans and the negative constraints of development control. Development control involves the approval and refusal of planning applications by planning authorities and the Secretary of State for the Environment. Many disciplines contribute technical advice regarding planning but technical advice is just one of the factors influencing any decision since planning authorities are charged with considering all material considerations.
The value of geology in planning
Authors: Legget R. F.
Published: April 2008

Geology is of fundamental importance as far as the planning of physical facilities and individual structure is concerned and recognition of this allows wise use of urban and rural land. As land is the surface expression of the underlying geology, planning should not proceed without fully appreciating geological conditions. Foundation, tunnels, transportation routes, etc. depend for their stability and performance on the geological setting.

There are, however, three aspects of geology related to areal planning which are not quite so obvious. First, prior to land being developed it is desirable to know if any useful materials can be retrieved from it before construction starts. Sequential land planning is therefore important. Secondly, there is likely to be an increased utilization of underground space in the years ahead. Thirdly, all those concerned with planning must realise that groundwater is a dynamic system and that, in particular, watertables can rise and fall, and thereby can influence subsurface structures.
A review of engineering geological and geotechnical aspects of town and country planning with particular reference to minerals and the extractive processes
Authors: Hake S. S.
Published: April 2008

The objective of this paper is to demonstrate the importance of, and connection between, Town and Country Planning matters and the need for engineering geological and geotechnical assessments. A brief review is given of the development plan system including the respective aims and intentions of both County and Local Structure Plans. Current planning law and building regulations are described from the point of view of stability of structures in the long term, together with comment so far as liability is concerned. The control of mineral workings is also briefly described in both planning and engineering geological terms. In addition, mining rights are discussed in lay terms from the mineral estates point of view. The underlying theme is with regard to minerals and the extractive processes.

The paper includes conclusions and recommendations which follow consideration of these issues in the light of the experience gained from undertaking detailed assessments with respect to planning issues, environmental impact, and stability considerations associated with opencast working and construction operations in areas affected by past, present and future underground mining at various depths. These conclusions deal with the applications of engineering geology and geotechnics within the current planning framework. Finally, recommendations are made concerning the future relationship between planning and engineering geology.
Data sources for planning: geomorphological mapping of landslides in north-east Derbyshire
Authors: Al-Dabbagh T. H. , Cripps J. C.
Published: April 2008

Categorization of land and the recognition of land surface processes of significance to development proposals are a fundamental necessity of effective land use planning and route selection. It is desirable that investigations of ground conditions should be initiated at an early stage of planning so that their impact may form the basis of the process. Since, generally, in these investigations an assessment of a large development area or route corridor must be made, low cost and rapid methods must be utilized.

A number of sources of suitable geological and engineering geological data are available, although not necessarily in an appropriate form. Much could be gained by undertaking interpretation of these data, although the value of doing so could be reduced or even negated if the user fails to appreciate any shortcomings of the data. Familiarization with the techniques of data collection would provide users with some knowledge of deficiencies and also equip them to commission data acquisition and specify styles of presentation most suited to their requirements. Geomorphological mapping is a relatively cheap and rapid method of acquiring data about the ground conditions. In the paper a number of examples are considered and, in addition, geomorphological mapping of landslides in north-east Derbyshire, is demonstrated.

One particular landslide has been subjected to detailed investigations in that accurate long term measurements of movement have been made. These reveal the rate and style of movement of different parts of the landslip which when considered together with the geomorphological map could form the basis of investigations for remedial measures.

The geomorphological mapping provides data not only confirming or otherwise the stability condition of the landslides, but also gives indications of the style of instability. The studies are advocated as useful sources of information for planning surveys. This particular work demonstrates the use of a rapid and inexpensive method of obtaining information about land instability.
Geophysical mapping techniques in environmental planning
Authors: Culshaw M. G. , Jackson P. D. , McCann D. M.
Published: April 2008

Geophysical information can be used to identify geological features, some of which may be a problem during the planning, design or construction of a new development. The location of magnetic dykes, the investigation of buried channels, or of landslips, the determination of the thickness of drift deposits or the identification of natural or man-made cavities are all problems which can be studied by geophysical surveying methods on both a regional or local scale. The information obtained can then be incorporated into factual or interpreted engineering geological maps for use by planners or engineers.

In this paper, the contribution that geophysical surveying methods can make at the planning, design, construction and monitoring stages of a development is examined and illustrated with a number of case histories.
Engineering geology input to the Greater Amman Master Plan
Authors: McCrae R. W. , Al-Ammouri A. F.
Published: April 2008

A study is presently being undertaken to formulate a Master Plan for the development of the urbanized area encompassing Amman in the Hashemite Kingdom of Jordan. This work includes reviewing data on many aspects, including geology and geotechnics which will influence future development. A detailed study of all the existing geological information for the area has been carried out to obtain an overview of the geological conditions to be encountered in the area.

The objective of the engineering geological input is to identify the location and causes of geotechnical problems and to formulate preliminary engineering solutions or policy proposals to mitigate their effect (if necessary by suggesting legislation). To facilitate this work a databank is being created to contain the extensive site investigation records which have been collected in the area.
The role of surface geophysics in the assessment of regional groundwaterpotential in Northern Nigeria
Authors: Reynolds J. M.
Published: April 2008

An analysis has been made of the usefulness of surface geophysical site investigations as part of a
rural water supply programme carried out in southern Kano State, northern Nigeria. Field work was
undertaken under the auspices of the Kano State Agricultural Rural Development Project in conjunction with
Groundwater Development Consultants (International) Ltd, Cambridge. The database for this study consists
of the results of surface geophysical site investigations at over 200 rural villages and comprised electrical
resistivity and/or electromagnetic ground conductivity methods together with hydrogeological data from
boreholes drilled as tubewells. The groundwater potential of southern Kano State was determined as a result of
field studies of hand-dug wells, water table levels, geological and geomorphological mapping, the use of aerial
photographs and, in particular, surface geophysics. Areas with poor groundwater potential were successfully
highlighted. A drilling programme was planned on the basis of these field studies which allowed the drilling rigs
to be used to maximum effectiveness providing successful tubewells whilst the more problematical sites were
investigated further. Wildcat wells sited without the aid of geophysics and drilled in the Basement Complex of
the Younger Granite terrain in Kano State resulted in unacceptably high failure rates (
c.
70%). Once
geophysical methods were introduced, the failure rate fell to less than 32% and, following further development
of geophysical field and interpretation techniques, the final failure rate was around 17%. For a project whose
target was 1000 successful tubewells, each costing of the order of £15,000, the saving to the client as a result of
reduced number of failures was of the order of £5 million. The use of resistivity surveys, especially in conjunction
with electromagnetic induction methods, has proved invaluable in the evaluation of groundwater potential and
the planning of extensive drilling programme in southern Kano State.
The use of land capability and land suitability classifications for planning purposes in Scotland
Authors: Bibby J. S.
Published: April 2008

The Department of Agriculture and Fisheries for Scotland (DAFS) have a responsibility to comment on all proposed changes of use in agricultural land in Scotland, whether this be to urban and industrial use or to forestry. The Macaulay Institute for Soil Research, through its Department of Soil Survey, has mapped the soils of Scotland, demonstrating in the process very clear links between the underlying solid and drift geology, and soil development and land use. Two series of interpretative maps have been produced, one at 1:250 000 of the entire country and one at 1:50 000 of the arable lands. These incorporate both climatic and site factors with soil type to provide a classification of agricultural potential. This work will be implemented in Scotland by DAFS as part of their planning-related functions in 1987. This paper describes the links between geology and soil maps, and the approaches taken in both land classification compilation and application. In conclusion, the basis for land suitability maps for specific purposes, now being actively developed to provide further guidance for assessing the impact of land use change in Scotland, is described.
Thematic mapping of the abandoned mining hazard: a pilot study for the South Wales Coalfield
Authors: Statham I. , Golightly C. , Treharne G.
Published: April 2008

The Department of the Environment and the Welsh Office jointly sponsored a South Wales Desk Study into the feasibility of producing thematic maps of the Mining subsidence risk for planners. A method was to be developed and tested for a 25 km
2
Pilot Area centred on Ebbw Vale.

The study was started by collecting geological and mining data for the Pilot Area and compiling this information on a map. It was then intended to prepare the mining subsidence map from this map by back analysing subsidence incidents to determine the hazardous areas. This simple approach could not be followed for two reasons. First, the record of mining was incomplete and it was therefore necessary to define ‘worked’ seams and areas from the total historical record and not only from the surviving mine plans. Secondly, insufficient subsidence incidents were discovered in the Pilot Area to carry out meaningful back analysis.

The study was extended to collect all readily available records of subsidence incidents throughout the Coalfield. A total of 388 were traced, mainly dating from 1960. About threequarters were collapses through superficial materials and were either close to the outcrop or above mine entries, the remaining 25% propagated to the ground surface through rock. The upper limit of migration was typically 8 times the extracted height where the dip was shallow, incrasing to as much as 18 times for steep dips. Selected grout contracts and opencast mining sites were also examined to gain information on the present condition of old workings and to study the ‘reputations’ of the various seams for voids.

The results of the coalfield study were applied to the Pilot Area to produce a 1:10 000 scale Development Advice Map, ‘Mining Subsidence for use by developers and planners’. The map is zoned to show areas where specialist advice is necessary to support a planning application and it also shows all mine entries traced by the desk study. The method of production is general for the South Wales Coalfield and further maps could be prepared, using the Coalfield Study, quickly and cheaply.
Development of resources
Authors: Taylor R. K.
Published: April 2008

This review compares and contrasts opencast coal-mining, dolomite quarrying and an open pit tungsten proposal with the planning impacts which affect new underground coal-mines. Deep-mining is emphasised in view of its past widespread effects in urban areas of Britain. Papers in the session on mining subsidence, long-term quarry slopes and sand and gravel construction materials are also considered in the context of the present planning system.
Environmental planning and mineral development: the case of Hemerdon Mine
Authors: Jone A. R.
Published: April 2008

In 1981 a planning application was submitted to mine tungsten and tin at Hemerdon, near Plymouth, close to the edge of Dartmoor National Park. Considerable concern was expressed about the possible environmental damage which could result from this major opencast mining and waste disposal operation. Against this are set the potential benefits to the local and national economy. After a public inquiry in 1982 the Secretary of State refused permission but indicated improvements to the visual aspects of the processing plant and waste disposal area which would be regarded more favourably in a new submission. A revised plan was submitted in 1985 which, while still not satisfying objectors, was passed by Devon County Council, subject to conditions.
Planning and geotechnical considerations for redevelopment of derelictindustrial land in London docklands
Authors: Gahir J. S. , Clark A. R. , Martin P. L. , Howland A. F.
Published: April 2008

The redevelopment of former docklands, with docks frequently backfilled by end tipping through
water, requires careful planning and a proper understanding of the geotechnical properties of the materials
involved. An overall scheme for development of part of the former Surrey Commercial Docks Southwark,
disused since 1960s, was formulated by London Docklands Development Corporation to provide a new
environment encompassing housing, schooling, a shopping centre, social and recreation facilities and light
industrial units.

This paper presents a review of the development strategy and planning aspects of the development of Surrey
Quays with particular reference to the assessment of the former wharf areas and the quality of the dockfill.
Planning considerations, along with the role of geotechnics within the infrastructure development plan, are
presented. The results of geotechnical investigations which included an extensive phase of field and laboratory
testing, led to a ground improvement programme consisting of surcharge loading and vibro-replacement.
The geological input to the reclamation process in forestry
Authors: Moffat A. J.
Published: April 2008

A geological understanding of a site is important if it is to be reclaimed successfully for a forestry after-use. Comprehensive site investigations before mineral extraction enable sensible decisions to be made concerning landform and drainage design, cultivation methods and species selection. Land given back to forestry is often of poor quality, and geological information helps to maximise the opportunities available. These points are illustrated with recent examples from British forestry practice.

The Town and Country Planning (Minerals) Act 1981 is discussed with reference to reclamation to forestry. The aftercare condition imposed by the Act makes treatments of the land such as drainage, cultivation and fertilising the concern of the mineral operator for 5 years following restoration. However, compared with other land uses, forestry is more profoundly affected by the restoration process. Hence, early consultations between planner and forester are essential.
Coastal erosion in the eastern half of Christchurch Bay
Authors: Nicholls R. J. , Webber N. B.
Published: April 2008

Christchurch Bay has a long history of shoreline recession and this has given rise to some major coastal engineering problems. An area of particular concern is Hurst Beach at its eastern end, where the maximum rate of recession has increased from 1.5 m a
-1
(1867 to 1968) to 3.5 m a
-1
(1968 to 1982). Hurst Castle itself is now subject to wave attack on part of its frontage. The littoral sediment movement was assumed to be essentially continuous around Christchurch Bay, but, in fact, a littoral drift sub-cell boundary (i.e. a partial barrier to littoral drift) is present in the vicinity of Hordle Cliff. Therefore, the increased recession of Hurst Beach is a local problem. Milford-on-Sea is situated on a thick sequence of Pleistocene Gravels, whose erosion contributed substantially to the maintenance of Hurst Castle Spit as a major physiographic feature. However, a series of coast protection works were constructed to protect Milford-on-Sea between 1936 and 1968, removing this important source of sediment.

In the long term, without any further human interference, recession rates of up to 6 m a
-1
will probably occur along Hurst Beach. A breach of Hurst Beach is a major concern, as it would create an island at Hurst Castle and expose the vulnerable, low-lying, northern coast of the West Solent, including the village of Keyhaven, to increased wave attack and tidal scour. Ecologically important saltmarshes would also be destroyed.

Shingle renourishment is the only environmentally acceptable engineering solution. Limited renourishment has already commenced. Any cost benefit decisions must consider the wider implications of a breach in Hurst Beach, including environmental and ecological considerations.

This case study demonstrates the importance of a detailed understanding of both the littoral and offshore sediment movement for the planning of coast protection.
The geological input into land-use planning in Lothian Region, Scotland
Authors: Henry J. J.
Published: April 2008

Strategic land use planning in Lothian Region is administered by Lothian Regional Council while the four District Councils and the New Town Development Corporation deal with local planning issues. Lothian Regional Council's Structure Plan interprets government guidelines setting out the strategic guidance for the development of the Region which is reflected in Local Plans.

The paper describes the geological input into the land-use planning system at both strategic and local levels in relation to the stability of land and minerals required by the extractive industries.
Geotechnical input to land use planning in Hong Kong
Authors: Koirala N. P. , Hee A. , Burnett A. D.
Published: April 2008

The importance of efficient landuse and town planning in Hong Kong has been accentuated in recent years because of the shortage of readily developable natural terrain and the high price of the man-made land which is consequently required to be formed under the adverse conditions of hilly topography, difficult geology and severe rainfall. The allocation of land, for all requirements in the community, is undertaken in Hong Kong by means of a land planning procedure by which boundaries for different classes of landuse are defined and delineated on statutory Outline Zoning Plans while more detailed development proposals and site layouts are shown on Departmental Plans.

The paper describes the different types of land planning documents dealt with by the Geotechnical Control Office and discusses the objectives and techniques of geotechnical assessment of these plans. The main geological and geotechnical hazards and constraints faced during land development are also discussed and reference is made to case histories of geotechnical input to specific projects to illustrate the role of engineering geology in the land planning process.
Ground movements due to tunnelling in hard rocks
Authors: Ward W. H.
Published: April 2008

Movements caused by tunnel construction in continuous and discontinuous hard rock are discussed briefly and generally in relation to typical topographic and effective ground stress conditions. Larger displacements are found in open-jointed rocks at shallow depth, and adjacent to tunnels built too close to steep valley walls where stress conditions are adverse.

In deep tunnels, where the ground stresses are sufficiently adverse to cause local rock failure, convergence controlled by supports allows the rock to dilate locally and attenuates the movements away from the tunnel.

Reference is made to a special form of upward collapse in unsupported tunnels at moderate depth, which may migrate to the surface in discontinuous rocks with near-vertical joint sets and thin, near-horizontal and weak bedding, in the long-term.

Two case records are given of water at high pressure in adjoining strata causing bursting of intervening rock into tunnels, one from above the tunnel and one from below.
A case study of two tunnels driven in the Singapore ‘Boulder Bed’ and in grouted coral sands
Authors: Shirlaw J.N. , Doran S. , Benjamin B.
Published: April 2008

As part of the construction of the Singapore Mass Rapid Transit, two tunnels had to be driven from a shaft to Raffles Place Station. Each drive was approximately 170 m long and was mostly in the Singapore ‘Boulder Bed’. This formation underlies much of the Central Business District of Singapore, and is thought to be a colluvial deposit comprising sandstone boulders in a stiff clay matrix

The first 60 m of the upper tunnel had a mixed face with an old coral reef above axis and the Boulder Bed below it. The corals and sands of the reef were highly permeable and had to be injected with chemical grout before tunnelling commenced.

The Raffles Place area is in the commercial heart of Singapore and the tunnels passed close to two high-rise buildings. One of these buildings had an underground car park within 5 m of the upper tunnel. Shield drives in the Boulder Bed had recorded high surface settlements, and there was concern about the underground car park which was known to be sensitive to settlement. It was proposed to drive the tunnels using the New Austrian Tunnelling Method, and one of the justifications for choosing the technique was that the resulting soil movements could be minimized. In order to check this claim surface settlement arrays, inclinometers and extensometers were installed to monitor movements caused by the tunnelling.

Records of ground movements measured are presented, and compared with the movements recorded above shield driven tunnels in the same deposit. Methods of grouting and testing used in the coral and sands are also reported.
Tunnelling through frozen ground: a case history at Iver, Buckinghamshire
Authors: Griffin A. R.
Published: April 2008

As part of the Three Valleys Water Scheme a 6 km long 2.54 m internal diameter tunnel was driven from Iver Treatment Works (Bucks) to Wraysbury Reservoir. The general geology of the area consisted of 2–3 m of river terrace gravels overlying London Clay and Woolwich and Reading Beds. During investigations carried out in advance of the tunnel face anomalous ground conditions were detected. A deep gravel filled scour hollow was located which cut down 30 m into the London Clay onto the proposed tunnel line. In addition the underlying clay and water bearing sands (under artesian pressure) of the Woolwich and Reading Beds had been folded upwards.

Extensive ground treatment was carried out consisting of an initial programme of claquage and gel grouting followed by ground freezing.

Measurements of tunnel and lining movements were carried out initially in the wedge block line section and through the frozen section. Measurements indicated that ground treatment had been successful with negligible ground movement towards the tunnel face and with little lining deformation.
Ground losses during bored piling through weathered Keuper Sandstone in Bristol
Authors: Thomas G. G. , Mojabi M. S.
Published: April 2008

The redevelopment of Brunei House in Bristol required that the 1820 facade be retained. The facade was badly cracked having been constructed on only a shallow masonry strip footing in thick historical fill and up to 5 m of soft Keuper clays and-sands. The groundwater table was at approximately 3 m depth. The Keuper Sandstone, at typically 7 to 10 m depth had weathered to a loose sand and the site investigation had encountered sub-artesian water pressures in this stratum.

The new building required piled foundations, which had to be installed alongside the facade. The inevitable vibration during driven piling meant that bored piles were the preferred solution. The integrity of continuous flight auger piling had not been adequately proven in these ground conditions, and such piles were also rejected.

It was appreciated that with conventional bored piling, ‘boiling sand’ would prove to be a problem in the saturated Keuper Sandstone, which had weathered to a sand. The paper describes how the volume of ground loss was reduced to an acceptable amount by maintaining satisfactory hydraulic head. Twin telescopic casings were also experimented with in an attempt to seal the pipe casings into the underlying Carboniferous sandstone bedrock, thus reducing the ground loss.

The facade was supported with a large concrete counter balance, and a scaffolding grillage was designed to allow the facade to articulate during the piling. Details are given of the thorough programme of monitoring which was undertaken.

The ground loss into the pile bores was successfully controlled and the facade moved in the manner predicted.
A case study illustrating the use of boundary element stress analysis in deformation prediction
Authors: Price C. H. de G. , Legge T. F. H.
Published: April 2008

A case history is presented in which movements around an underground powerhouse were predicted using two dimensional boundary element stress analysis. The powerhouse, for the Kiambere Hydro-Electric Project in Kenya, is situated in fresh, very widely jointed migmatite at a depth of 128 to 162 m below ground level.

Results of early analyses which employed the vertical and horizontal
in situ
stresses are presented. These are compared with the results of analyses employing an inclined stress field more closely approximating to the true three dimensional conditions. Shear stresses, which had to be ignored in the earlier analysis, were thus reduced. Finally, the effects of minor excavations around the cavern are assessed and included into the results of the cavern analyses, producing a pseudo three dimensional analysis. The absolute values of the deflections were extremely limited but are of relatively little significance in themselves. More importantly, the case study illustrates the high degree of precision which extensometer monitoring can attain, and the level of correlation achieved between predicted and observed deformations. The
in situ
stress testing carried out for the study is put into its tectonic context adjacent to the East African Rift Valley.
Grouting-induced ground movements
Authors: Gregory B. J. , Venter I. S. , Kruger L. J.
Published: April 2008

The Far West Rand in the Transvaal Province of South Africa is the location of some of the world’s largest gold mines. The area is underlain by dolomite which is sub-divided into a series of separate groundwater compartments by dykes. The inflow of water from the overlying dolomite into these deep-level gold-mines directly influences their continued development and operation. A policy of dewatering some compartments has therefore been adopted due to economic and safety considerations. However, such dewatering has in the past resulted in large-scale ground movements in the form of sinkholes and dolines, causing damage and collapse of structures and, in some cases, loss of life.

The dewatering of the Gemsbokfontein Compartment commenced in 1986. Prior to this a field trial was conducted to assess the potential of grouting as a preventative geotechnical treatment for protecting an important traffic route against the effects of sinkhole development.

During the field trial ground movements occurred as a result of the grouting. This paper describes the monitoring of these movements and the operational procedures adopted to minimize the induced settlements. On the basis of monitoring and analysis of the settlements it was concluded that the movements were the surface manifestation of sub-surface erosion of wad at depth due to the movement of grout across steeply inclined dolomite. Following the field trial, a major grouting contract along those sections of the highway identified as high risk was completed before the start of dewatering. During this operation, ground movements were again recorded and ascribed to erosion and disturbance of the wad due to grouting. The procedures established during the field trials were reintroduced and the contract was completed with minimal damage to the carriageways.
A cost-benefit analysis for stabilizing shallow Bath Stone mine workings at Corsham, Wiltshire
Authors: Thomas G. G.
Published: April 2008

A conventional ground investigation for an elevated tank at Box Hill near Corsham in Wiltshire, proved 5 m of thinly bedded oolitic limestone, beneath a veneer of fill. Four weeks before the construction works were to be put out to tender in 1986, a plan of the Brewer’s Yard Mine came to light, which indicated that there were old stone mine workings beneath the tanks, at about 17 m depth. A geotechnical reassessment was therefore commissioned.

An examination of the workings revealed that three significant roof collapses had occurred within the mine, directly below the proposed tank. The largest fall had migrated about 3 m above original roof level. It was concluded that future falls were likely. However, an existing elevated tank was located over old workings and although it had been levelled regularly over its 50 year life, it had showed no signs of movement. Consequently a cost-benefit analysis of a number of options was undertaken.
Geotechnical influences upon longwall mining
Authors: Isaac A. K. , Follington I. L.
Published: April 2008

This paper describes geotechnical influences upon the planning, development and implementation of the longwall mining system. The effects of these factors have been assessed from a series of comprehensive investigations carried out in the South Wales and South Nottinghamshire Coalfields. All the investigations involved the setting up of monitoring sites employing specially designed instrumentation to monitor the parameters outlined in the paper. In addition, detailed structural and lithological investigations have been carried out involving underground mapping, diamond drilling and logging, geotechnical core logging and physical rock property determinations.

This information has been brought together for each site and a characteristic deformation mechanism identified. These are presented in the paper with a series of three dimensional figures indicating the primary influences.

The value of these types of studies is outlined in the paper both in the planning of subsequent extraction and as improvements to current operational systems.
Monitoring of ground movement above an abandoned limestone mine
Authors: Longworth T. I.
Published: April 2008

Precision water-level gauges, magnet extensometers and invar wire extensometers have been designed and used by the Building Research Establishment to continuously measure horizontal and vertical ground movements above the abandoned Castlefields limestone mine, Dudley. All the instrumentation operated automatically and was controlled by computerized data logger. Details are given here of instrument design and performance, and of the observed ground movements over a three year period, including before, during and after filling of the mine with rock paste.

Ground displacements have been very small, indicating general stability of strata above the mine, despite known frequent falls from the mine roof prior to filling with rock paste. Rock paste has been demonstrated to be an acceptable new technique from the standpoint of not causing a temporary increase in mine instability
during injection.

Trial borehole electro-levels are described and recommended as robust economical devices which can give warning of ground subsidence over mines.