bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dispersive soils: a review from a South African perspective
Authors: Bell F. G. , Maud R. R. 
Published: November 2007

Abstract
Dispersive soils deflocculate in the presence of relatively pure to form colloidal suspensions and are therefore highly susceptible to erosion and piping. Such soils contain a higher content of sodium in their pore water than other soils. However, there are no significant differences in the clay contents of dispersive and non-dispersive soils. Unfortunately no one test is successful in identifying these soils in every instance. Because the principal chemical factors influencing dispersive behaviour in a soil are exchangeable sodium and cation exchange capacity, these two parameters are frequently used in South Africa to help distinguish between dispersive and non-dispersive soils. Nonetheless it is recommended that more than one test is used to identify these soils and pehaps a rating system could be adopted. Dispersive soils are widely distributed in South Africa and are derived from a variety of rock types. They are commonly found in regions where the annual rainfall is less than 850 mm. Suspicion of their presence is indicated by the occurrence of erosion gullies and piping. In some parts of South Africa dispersive soils have to be used for construction purposes since no other soil material is available. Hence dispersive soils have been used in the construction of earth dams and embankments. Serious piping and failures have occurred, especially when they have been used for earth dams. However, if an earth dam is properly constructed, incorporating filters, impermeable core and, in particular, correctly compacted, then it should perform satisfactorily. Dispersive soils sometimes can be stabilized by treatment with lime or gypsum.
Mechanical properties of jet grouted soilcrete
Authors: Fang Yung-Show , Liao Jyh-Jong , Lin Ta-Kang 
Published: November 2007

Abstract
To investigate the mechanical properties of jet grouted soilcrete, uniaxial compression tests, Brazilian tests and ultrasonic tests were conducted on a number of samples. It was found that the uniaxial compressive strength, modulus of elasticity, failure strain, tensile strength and P-wave velocity of soilcrete increase with increasing dry density. Dry density should be one of the critical criteria to control the quality of jet grouting. Significant variation of strength was monitored for soilcrete from the same depth because of the non-uniform mix of soil and grout with a high-pressure jet. The maximum axial and lateral strain at failure were found to be 0.62% and 0.20%, respectively. These values are relatively close to the failure strains for concrete, rather than for soil. The Brazilian tensile strength varied between 1/10 and 1/30 of the uniaxial compressive strength.
The effect of crystal size on geotechnical properties of Neogene gypsum in Crete
Authors: Papadopoulos Z. , Kolaiti E. , Mourtzas N. 
Published: November 2007

Abstract
The gypsum deposits to the southwest of the city of Heraklion, northern Crete, have been widely used as a construction material from early times either as structural or ornamental stone or foundation rock. In the study area, they were exploited and used extensively for the construction of the Knossos Palace. Although gypsum is considered as a basically weak and soluble material, it has withstood the test of time and the occasional failure problems have been observed only recently after the excavations and especially after the completion of the early restoration works. The paper attempts to highlight the geotechnical properties of gypsum and relate them to the various gypsum formation mechanisms and environments.
Discussion on ‘Engineering Geology of North Lantau’ by C. A. M. Franks & N. W. Woods
Authors: Franks C. A. M. , Woods N. W. 
Published: November 2007

M. D. Howat writes: The authors' review is admirably complete yet makes no mention of the sensitivity of the marine clays, especially in relation to the problems posed by the so-called “lower marine deposits” which could be attributed either to the base of the Hang Hau or the top of the Chek Lap Kok Formations.

The sensitivity of the marine soils of Hong Kong, first reported by Holt (1962), was noted in North Lantau boreholes by Fung
et al.
(1984) and observed in situ by Howat (1985, 1987) in excavations and tunnels for the Island Line of the Hong Kong Mass Transit Railway. The sensitivity can be gauged on Fig. 1 which compares the Chek Lap Kok liquidities with those of the sensitive clays analysed by Skempton & Northey (1952). There was at the time of publication some discussion on its engineering significance (Endicott 1984; Howat 1984).

While this sensitivity may not pose a particular problem for the very weak upper marine deposits, whose yield stresses are exceeded during large-scale reclamation allowing consolidation to occur (Koutsoftas & Cheung 1985), it could be vital for the stiffer lower marine deposits whose higher yield stresses are approached, but not exceeded, and can therefore find themselves in a rather delicate metastable condition after a considerable thickness of fill has been placed. The gradual breakdown of the resulting highly stressed soil structure with time can explain the 'stagnation of pore pressure dissipation' (continuous regeneration of excess pore pressures?) to which the authors allude.
The
Review of Transport Research Laboratory research on highway drainage
Authors: Farrar D. M. 
Published: November 2007

Abstract
Drainage measures are an important means of ensuring the stability of highways and associated structures. Much of the TRL research on highway drainage has been directed towards examining the field performance of drainage systems, usually over extended periods. This paper describes studies mainly by TRL on edge of pavement drainage, slope drainage, drainage to retaining structures, and drainage blankets. The results are described in relation to current UK practice.
Swelling behaviour of calcareous clays from the Eastern Province of Saudi Arabia
Authors: Abduljauwad S. N. 
Published: November 2007

Abstract
The development of heave and swelling pressure in the natural calcareous expansive soils in the Eastern Province of Saudi Arabia causes major damage to structures constructed on or in them. The behaviour of expansive soil depends on the predominant type of clay minerals present, the cementing agents that bind these clay minerals and other physical and chemical properties. This paper presents the problems and the geotechnical and physicochemical properties of the calcareous expansive soil deposits in the Eastern Province of Saudi Arabia. X-ray, thermal and chemical analyses and scanning electron microscopy were used to estimate the type and quantity of clay and non-clay minerals and fabric of the investigated soil. The swelling potential was determined using a conventional oedometer test. A field test conducted for measurement of heave was compared with heave estimated from laboratory- tests, Results showed that the investigated soil had moderate to very high swelling potential and the heave estimated from the suction method was very close to the value measured from the field test.
Landslide and erosion hazard mapping at Ok Tedi copper mine, Papua New Guinea
Authors: Hearn G. J. 
Published: November 2007

Abstract
Landslides and erosion pose significant hazards to mining and engineering activity in the remote mountainous terrain of Western Province, Papua New Guinea. The investigation and containment of these hazards have been the concern of the Ok Tedi open-cast copper mine since engineering feasibility studies began in 1978. Subsequent terrain hazard mapping has identified numerous landslides and rock avalanche deposits in the Ok Tedi catchment and in the immediate vicinity of the mine, ranging from very low frequency, catastrophic rock avalanches through to mudslides and mudflows that recur on a daily or weekly basis. This mapping formed part of a multidisciplinary geotechnical study instigated by Ok Tedi Mining Limited and comprised detailed slope inventory, geomorphological mapping combined with air photograph interpretation nd a review of pre-existing structural geological and geotechnical data. The study area was sub-divided into 245 zones and assigned hazard and risk categories or levels derived from the field data. These classifications were presented in map form at 1:10 000 scale along with prioritized recommendations for further investigation, monitoring and remedial action, where appropriate.
The geomorphological controls on seismically triggered landslides during the 1908 Straits of Messina earthquake, Southern Italy
Authors: Murphy W. 
Published: November 2007

Abstract
Investigation of landslides which have been located from contemporary accounts of the Straits of Messina earthquake of 1908 reveals that a failure envelope for the slopes may be drawn on the basis of slope height-slope angle relationships for static and dynamnic stresses. As would be expected there is a decrease in stability during the earthquake to a degree which is almost certainly linked to the generation of pore water pressures. However, a region of the failure envelope shows much greater decrease in stability; this section of the curve describes the stability of low slope height-high slope angle forms. The area for which this stability curve has been calculated is affected by a nearfield earthquake. It is suggested that these slopes are suffering from forced vibration from high-frequency accelerations. In support of such a hypothesis of a geomorphological control is the observations that many of the landslides along this section of coastline occurred at topographic irregularities.
Engineering performance of some coarse-grained arid soils in the Libyan Fezzan
Authors: Fookes P. G. , Gahir J. S. 
Published: November 2007

Abstract
Arid engineering soils are those whose properties have been conditioned by an arid climate: they differ from soils in temperate or humid climates mainly in the role played by water. In temperate climates coarse-grained materials having less than 12 0.000000ines will generally behave as free draining soils. This case study shows that in a hot desert environment some sands with up to 30 0.000000ines, of low plasticity or no plasticity, also demonstrate behaviour which is consistent with that of free draining soils.
The near-surface materials studied were the subject of a small investigation by the contractor during Phase II of the Great Man-made River Project, Libya. They were mainly rounded to subrounded granular particles resulting from mechanical action of wind and water. The particles are predominantly limestone and quartz fragments derived from the local Cretaceous and Palaeocene shallow marine, carbonate-rich bedrock sources: mid-Tertiary basic volcanics and younger Tertiary continental deposits also contribute.
Windblown, mainly carbonate, silt-sized dust is characteristic of the local desert conditions. It is generally angular and often mixed with the sands. Occasional wetting and subsequent evaporation have resulted in a very weak cementation (calcite and occasionally gypsum) of the granular particles. This holds the grains, preventing them from being free-flowing, and the resulting soil has some special properties, including for example, large variations in grain size distribution between dry and wet sieving; low plasticity index of the fines in predominantly granular soils; high dry density upon compaction and good load bearing characteristics.
These sands are considered typical of hot arid, coarse grained deposits in a carbonate rich geomorphological environment. Vast areas of sands in the Middle East and elsewhere with carbonate bedrocks are likely to be similar to these and their behaviour is also likely to be influenced by a carbonate fines content.
Effect of fly ash with lime and cement on the behavior of a soft clay
Authors: Indraratna A. S. , Balasubramanian A. K. , Khan M. J. 
Published: November 2007

Abstract
The effect of fly ash on the strength and deformation characteristics of Bangkok clay is discussed in the paper. Lime or cement has been added as secondary constituents to further enhance self-hardening of the blended mix. For example, unconfined compression tests reveal that after two weeks of curing, a 18 0.000000ly ash and a 5 0me treated Bangkok Clay attains a compressive strength 2-3 times greater than that of the natural clay. However, if lime is replaced by cement, the initial rate of strength development increases significantly. Excessive fly ash contents (greater than 25%) cause tensile splitting of unconfined specimens. The compressibility of fly ashcement treated soil is considerably less than that of the natural clay. As the fly ash content exceeds 10 0.000000or a constant cement content of 5%, the increase of the equivalent yield pressure becomes significant. The reduction in compressibility is also associated with a corresponding increase in the coefficient of consolidation. The triaxial tests confirmed that fly ash-lime and fly ashcement treated specimens indicate a much higher sheafing resistance by improving the apparent friction angle, although the effect on the cohesion intercept is marginal. The stressstrain response changes from a normally consolidated state to an over-consolidated state as a function of the fly ash content. The findings of this study present a rational basis for the development of appropriate constitutive models for chemically modified soils.
Engineering geology of the Bukit Timah Granite for cavern construction in Singapore
Authors: Zhao J. , Zhou Y. , Sun J. , Low B. K. , Choa V. 
Published: November 2007

Abstract
The Bukit Timah Granite forms one-third of the surface area of Singapore. In recent studies, the engineering geology and hydrogeology as well as the rock mass properties of the granite formation were investigated to assess its potential as a host medium for large rock caverns. This paper presents the results of the recent field and laboratory investigations, including engineering and mechanical properties, weathering characteristics, discontinuity systems, groundwater regime and general rock mass quality. The results conclude that the Bukit Timah Granite has good potential for underground cavern construction.
The survey and recording of historic monuments
Authors: Emerick Keith 
Published: November 2007

Historic monuments are a valuable asset and provide information on man's past activities. They also provide the engineering geologist with useful guidance on rates of weathering. Man has, at a known time, taken rocks from the ground and combined them with other building materials such as mortars and renders. All of these materials have been exposed to weathering, which is now well advanced in some stones or structures. The work of the conservation bodies records,
inter alia
, the present status of the weathering process.

The photographs were all taken at Fountains Abbey, near Ripon in Yorkshire. The Abbey was founded in 1132 but has been without a roof or windows since the Dissolution of the Monasteries in 1539. Some remarkable contrasts in weathering are apparent. The severe weathering shown in Fig. 4 is probably related to winds coming in through the large open East window; conversely the render and limewash seen in Fig. 7 is still in very good condition after over 400 years of exposure, albeit in a less exposed location. The records of such a building provide documentation on rates of weathering in engineering time, and also provide insights into the effect of various processes on a range of different materials.
The obligation to record historic monuments satisfies a number of criteria. The survey produced is known as an ‘as found’ record of the building, i.e. its appearance before works take place. This can be used as a record of archive standard and also as the base for detailing
Engineering in weathered rock
Authors: Hencher S. R. , McNicholl D. P. 
Published: November 2007

Abstract
The potential problems to be faced when engineering in zones of weathered rock are reviewed. Difficulties in formulating realistic geotechnical models by standard methods of site investigation and routine testing are emphasized and the consequences of being wrong are illustrated by examples. Alternative approaches for delineating weathered zones for design are presented. The constraining influence of particular characteristics of weathered zones on methods of construction are discussed with reference to brief case histories.
Honeycomb weathering of Carboniferous sandstone in a sea wall at Weston-super-Mare, UK
Authors: Pye K. , Mottershead D. N. 
Published: November 2007

Abstract
Blocks of Forest of Dean Stone, an arkosic, clay-rich sandstone of Lower Carboniferous age, which were used in the construction of a sea wall at Weston-super-Mare in the 1880s, now display extensive honeycomb weathering features. Spatial variations in the degree of weathering, together with geochemical evidence, suggest that marine salt spray has played a key role in the development of the honeycombs. Petrographic microscope and SEM studies indicate that the principal weathering mechanisms involved are granular disintegration and micro de-lamination induced by chemical alteration along inter-grain boundaries and differential swelling and contraction of clays within the rock.

Salt crystallization and hydration pressures within the rock pores appear to have played a minor role in this case. The formation of alveoli has been favoured by initial irregularities on the surfaces of the stone blocks which allowed differential ingress and retention of saline solutions. Progressive enlargement of the alveoli continues until the boundary walls between adjacent cavities are breached and the honeycomb layer disintegrates. Over the past century the maximum rate of surface lowering of the honeycombed surfaces at Weston-super-Mare has exceeded 1 mm a
-1
.
Three-dimensional geomodelling for offshore aggregate resources assessment
Authors: Orlić B. , Rösingh J. W. 
Published: November 2007

Abstract
Use of a three-dimensional geoscienfific modelling system in offshore sand resources analysis is described. The benefits of a three-dimensional approach to geological modelling are that geologists can concentrate on geological interpretation without the constraints embodied in a two-dimensional approach and geological models can be used directly for aggregate volume assessment, in terms of global and local estimates, with no need to construct isopachytes. An algorithm has been developed which, on the basis of the geological model and variable extraction criteria, yields parameters required for detailed extraction design: depth of dredging, volume of aggregate and ratio of aggregate to waste in the total extracted volume. In addition, the algorithm also accepts as input a three-dimensional geostatistical model of aggregate resource. Data from an offshore site investigated in relation to land reclamation for the Chek Lap Kok Airport, Hong Kong, are modelled, and results are presented for demonstration.
Borehole performance in alluvial aquifers: particulate damage
Authors: Blackwell, I. M. , Howsam P. , Walker M. J. 
Published: November 2007

Abstract
Particulate damage is often cited as a cause of permeability impairment around boreholes, producing a decline in well performance. The mobility of particles within a formation, with respect to both damage and recovery mechanisms, is not easy to quantify
Removal of such damage from the formation has been attempted using water and a variety of low concentration drilling fluids. The results demonstrate that, in normal stable media, the fluids' formation sealing properties outwiegh any special viscosity and particle carrying abilities they may have compared to water, even at low concentrations. Only where the medium was fluidized did the polymers show any advantages over water.
Particulate movement and redistribution under borehole operating conditions has been assessed for a range of artificial and natural formations. It has been shown that movement is limited mainly to formations with a bimodal particle size distribution. In formations with a log-normal distribution, particle movement is restricted to all but the finest particles. The key factor governing particle mobility is therefore the structure of the porous medium.
Particulate damage, however caused, cannot always be effectively removed using normal development and rehabilitation techniques, and should therefore be avoided in the first place, by taking greater care during the drilling, sample collection and analysis, design, construction and development of a borehole.
Reappraisal of time-dependent subsidence due to longwall coal mining
Authors: Goulty N. R. , Al-Rawahy S. Y. S. 
Published: November 2007

Abstract
Subsidence due to longwall coal mining may conveniently be considered as taking place in two phases: active subsidence as the face advances, and residual subsidence after it has come to a halt. Published data show that the dynamic subsidence profile at low face advance rates is independent of the advance rate itself. This finding is incompatible with the common practice of modelling subsidence as a simple viscoelastic process. Qualitative consideration of the mechanical processes taking place during active and residual subsidence shows that different timedependent behaviour during the two phases of subsidence is to be expected. We infer from reported observations of timedependent subsidence that the relaxation times involved during active subsidence are of the order of days, whereas the relaxation times involved during residual subsidence are of the order of one year. As different mechanical processes are involved during each phase, one should not attempt to predict the duration of residual subsidence from observations of active subsidence.
The hydrogeology of Western Europe: a basic framework
Authors: Crampon N. , Custodio E. , Downing R. A. 
Published: November 2007

Abstract
The principal hydrogeological provinces are identified and briefly described. The main aquifers are in the Mesozoic and Cenozoic cover which overlies the Hercynian basement. North of the Hercynian Front, an older cover of the Devonian and Carboniferous rocks, resting on Caledonian basement, contains aquifers of secondary importance. Groundwater is a very essential component of freshwater supplies in Western Europe.
Discussion on ‘The Chalk as a karstic aquifer: evidence from a tracer test at Stanford Dingley, Berkshire, UK’
Authors: Banks D. , Davies C. , Davies W. 
Published: November 2007

M. Price writes: Banks
et al.
(1995) address the nature of the permeability of parts of the Chalk aquifer, provide useful data from a tracer test, and draw attention to the potential dangers of disposing of agricultural and road run-off to swallow holes. The paper includes a calculation of fissure conductivity and aperture from the results of the tracer test. In this it has to be emphasized that the calculations relate to Darcian flow in an equivalent smooth, plane, parallel-plate opening, not the more likely turbulent flow in a natural fissure. The true average aperture of the fissure is therefore likely to be significantly greater than that calculated (Price 1987, 1996).

The situation described at Stanford Dingely is one where drainage originating from impermeable Tertiary strata flows onto the Chalk and sinks into the aquifer. The majority of active Chalk sinks appear to be of this type; the drainage sinking into them originates as run-off from other strata. Rain falling anywhere on the outcrop of the Chalk is normally able to infiltrate, so water flowing across the Chalk outcrop is almost invariably allogenic drainage or water that has infiltrated the Chalk and emerged as baseflow. Drainage to sinks is therefore a minor component of recharge to the Chalk.
The tracer test undertaken into at Stanford Dingley involved introducing tracer into a known point of entry in the aquifer, and observing its arrival at a known point of emergence. Such tests almost inevitably measure the speed of groundwater movement along a