bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geotechnical evaluation of untreated and cement-treated Ajali Sandstone from southeastern Nigeria
Authors: Eze E. O. , Suoware O. P. 
Published: November 2007

Abstract
The grain size analysis and the Atterberg limit values indicate that the Ajali Sandstone falls into the A-3 and SP-SW classes of the AASHTO and the Unified Soil Classification systems respectively. The low values of the coefficient of uniformity 2.9-3.4 show the deposit is uniformly graded and the soil is deficient in silt-clay fractions. At the optimum moisture content of 8% the untreated soil has a maximum dry density of 1.77 Mg/m3. The CBR of the soil when compacted to the standard Proctor optimum and soaked for three days is 10%. To establish the effective cement requirement of the soil, 5, 7, 9 and 110y weight of Portland cement was added to the soil. Results show that 80f the stabilizer meets the required minimum CBR of 100% and the 7-day uniaxial compressive strength of 1.4MPa (l.4 N/mm2). On ageing, the stabilized A-3 soil gains appreciably in strength.
Decay of building stones: a mineralogical model for Konark Sun Temple, India
Authors: Raymahashay B. C. , Sharma S. 
Published: November 2007

Abstract
The rapid decay of the famous sun temple at Konark is mainly due to the use of a highly weatherable khondalite rock as the construction material. A computer based weathering model indicates that the measured porosity of 7 to 8 0n weathered khondalite could have been produced if an original rock with 3 : 1 quartz to garnet weight ratio decayed to such an extent that 70 to 900f the garnet was altered. From the kaolinite and goethite generated as weathering products, the mole fractions retained would be 0.5 and 0.1 respectively.
Interpretation of field and laboratory shear strength data of a soft marine clay
Authors: Indraratna B. 
Published: November 2007

Abstract

Soft Muar Clay in Malaysia is of marine origin, and is characterized by a high water content that is close to or greater than its liquid limit. The variation of
in situ
vane shear strength is compared with various undrained laboratory tests conducted on undisturbed specimens recovered from different depths. The effects of the overburden pressure and Atterberg limits on the vane shear strength are discussed. Correlations between the field vane shear strength and the cone penetration resistance are also determined, and the effect of plasticity index on the normalized cone resistance is discussed. The results obtained for the Muar Clay are compared with other available data for selected soft marine clays. The use of the corrected and uncorrected vane strengths in the prediction of slip surface is also discussed.
Swelling characteristics of Madinah clays
Authors: Hossain Delwar , Matsah Mohammad Ibrahim , Sadaqah Bahaeldin 
Published: November 2007

Abstract
Six expansive clays from the city of Madinah, Saudi Arabia have been investigated. The expansive nature of these clays is due primarily to the presence of smectite. The basaltic lava around Madinah is considered to be the source of this mineral. Kaolinite and illite also present in these clays are thought to be derived by the alteration of smectite. Calcite occurs only in the ‘white clayey silt’ and in the ‘upper brown clay’. Qualitative estimates using plasticity index and clay fraction data suggest ‘low’ to ‘very high’ swell potentials of these clays. Laboratory swell-consolidation tests indicate that for initial liquidity index in the range of -0.91 to +0.32, the percent swell for these clays is 1.02% to 13.2% and the swell pressure range is from 58 kPa to 770 kPa, the higher values of these two parameters being observed for grey-green clays with liquid limit less than 120% and particularly at low moisture contents. The swelling characteristics of expansive clays depends on numerous factors making the prediction of volume change and swell pressure difficult. This paper discusses the use of multi-variate analysis to aid the prediction of these parameters for the Madinah grey-green clays. The progressive lowering of the groundwater table in the Madinah area is likely to promote more severe desiccation of Madinah clays in the future. In view of the high swell potential of Madinah clays, there are important implications in relation to foundation design in Madinah.
Pore size distribution and the durability of a porous limestone
Authors: Ordóñez S. , Fort R. , Garcia del Cura M. A. 
Published: November 2007

Abstract
A comparison of durability estimations based on mercury porosimeter data and experimental salt crystallization tests carried out on Bateig Stone from Alicante, Spain, establish that the main factor in the salt crystallization durability test is the ‘ink bottle’ pore system, identified by the presence of residual mercury in large pores after porosity testing. In addition, the results suggest that the commonly used indirect durability tests may not be considered a scientific definition of building stone behaviour.
Hydrogeochemistry of coal mine drainage and other ferruginous waters in north Derbyshire and south Yorkshire, UK
Authors: Banks David , Burke Sean P. , Gray Colin G. 
Published: November 2007

Abstract

Fifteen coal mine drainage waters from the Millstone Grit and Coal Measures of Derbyshire and Yorkshire have been compared hydrochemically with other iron-rich waters from spoil tips, natural springs and lead mine soughs in the area. The coal mine waters typically contained several tens of mg/l iron, with a range from 0.1 to 101 mg/l, and sulphate from 60 to over 1000 mg/l. The waters are undersaturated with respect to siderite. There is a strong linear correlation between iron and sulphate indicating that pyrite weathering is the dominant source of these parameters, although iron appears to be preferentially removed by precipitation or adsorption within the mines. The pH values of coal mine water are typically
c
. 6, although one water has a pH of 3.6, contains some 17 mg/l aluminium and lacks the saturation relative to gibbsite and kaolinite present in the other waters. The coal mine waters may be net acidic or net alkaline: there is some evidence to suggest that the former are typically derived from unsaturated, underdrained (i.e. drained from underneath the workings) shallow workings and the latter from saturated, overflowing workings.

The spoil tip waters are neutral to alkaline and saline. A possible explanation for this is the leaching of residual pore-water brines from the deep (several hundred metres) mined strata. The spoil tip leachates are poor in iron, which may be retained as iron hydroxides, sulphates or even siderite within the spoil.
Point load testing of weak rocks with particular reference to chalk
Authors: Bowden A. J. , Lamont-Black J. , Ullyott S. 
Published: November 2007

Abstract

The Point Load Test (PLT) was developed as an index test to predict the Uniaxial Compressive Strength (UCS) of core too broken for UCS testing. A correlation factor (
K
) between UCS and PLT strength of 24 has been proposed although this value is disputed. This paper investigates the value of
K
for chalk and other weak rocks using published and unpublished data sets and concludes that
K
is not a unique value even for a single set of specimens but is strength dependent, generally being between 10 and 20 for weaker rock (>25 MPa). It is often less than 10 for rocks of 5 MPa strength or less. Operator error is evaluated and considered to contribute to much of the reported scatter in Point Load Test results. The PLT is considered an appropriate and useful test for predicting the UCS of weak rocks provided that the ISRM methods are strictly observed and that samples with a range of strengths are tested to determine the variation in the correlation factor
K
with change in strength.
Influence of rainfall intensity and duration on slope stability in unsaturated soils
Authors: Ng C. W. W. , Shi Q. 
Published: November 2007

Abstract
Rain-induced landslides are major geotechnical hazards. The influence of infiltration under various rainfall, ground conditions on slope stability is still poorly understood. In this paper, a finite element parametric study was carried out to investigate the influence of different rainfall events and ground conditions on transient pore water distributions in unsaturated soils. A steep, unsaturated colluvium hillside in Hong Kong was chosen: the initial water table, rainfall intensity and rainfall duration were variables. Pore water pressures predicted during the transient seepage analyses were used as input groundwater conditions for subsequent limit equilibrium analyses of the stability of the slope. Shear strength variation due to the presence of matrix suction was also taken into account. It was found that the factor of safety not only depended on the intensity of rainfall and the initial groundwater table, but also on rainfall duration. A critical rainfall duration was identified, when the factor of safety was the lowest.
Discussion on ‘Reappraisal of time-dependent subsidence due to longwall coal mining’ by N. R. Goulty & S. Y. S. Al-Rawahy(Quarterly Journal of Engineering Geology, 29, 83–91)
Authors: Wilson E. J. 
Published: November 2007

E. J. Wilson writes: Goulty & Al-Rawahy conclude
that, since different mechanical processes are involved in
active and residual subsidence, one should not attempt
to predict the duration of residual subsidence from
observations of active subsidence. Whilst this is obviously
true in a literal sense, the possibility that active
subsidence may result in delayed and possibly prolonged
residual subsidence should be considered.
The authors quote two cases by Orchard & Allen
(1975) in the Durham Coalfield where the presence of
thick competent strata prolonged residual subsidence to
six years (Peterlee) and delayed the onset of residual
subsidence by four years (North Durham). It is significant that both cases showed broadened subsidence profiles.
They go on to quote Pine & Randon (1986) who
recorded bedding separation below the thick Lower
Magnesian limestone in the Selby Coalfield, where active
subsidence at the Wistow Mine had produced less than
half the predicted settlement, and concluded that bridging
in the Permo-Trias can persist until the adjoining
panels are worked out. Reference is made to further
examples presented by Orchard & Allen (1975) and
Collins (1978). In one of the cases quoted by Collins at
Pengam, residual subsidence came to a stop after 2.5
years, and was noted by Collins to form a large proportion
of the active subsidence. In that case however
the active subsidence had only been about half of that
predicted. At Pengam, as also at Bedwas, prolonged
residual subsidence was ascribed to the presence of very
thick Pennant Sandstone in the
Spheroidal weathering of Deccan Basalt: a three-mineral model
Authors: Chatterjee A. , Raymahashay B. C. 
Published: November 2007

Abstract
Spheroidally weathered boulders occur in Deccan Basalt near Sagar, India. A simplified weathering model was developed to depict the alteration of the three primary minerals bytownite, augite and magnetite to an assemblage of beidellite, kaolinite and goethite. It was concluded that the thin concentric shells characteristic of the boulders resulted from an increase in volume during weathering. An iterative computer program showed that maximum expansion can be achieved through an appropriate combination of initial modal composition, fraction of each mineral altered and the relative proportions of beidellite, kaolinite and goethite in the weathered rock.
The micro-scale hydrogeological properties of the Lincolnshire Limestone, UK
Authors: Greswell R. , Yoshida K. , Tellam J. H. , Lloyd J. W. 
Published: November 2007

Abstract

As part of an integrated study of the ‘dual porosity’ hypothesis, a detailed micro-scale hydrogeological study was conducted of the rock material from a quarry excavated in the Lincolnshire Limestone. Permeability and porosity determinations allow comparisons to be made with the lithostratigraphy and show that the matrix hydraulic conductivities are inconsequential in terms of groundwater flow. The relatively high porosities typical of these limestones, combined with large surface areas associated with the major bedding plane fissures, provide a mechanism in which diffusive transport can become a significant factor in contaminant migration. The diffusion coefficients (
D
*) of three tracers used in field investigations (bromide,fluorescein and amino g acid) were measured in each of the main rock materials from the site using both double reservoir and reservoir depletion techniques. In addition, an assessment was made of
D
* estimation using an electrical resistivity method. Alteration of the matrix due to calcite dissolution of the fissure faces creates a zone of enhanced permeability and porosity. The presence of a fissure fill results in a ‘multiporosity’ interface between the fissure and the matrix that may significantly increase the mass of contaminant entering the pore fluid by diffusion in comparison with a simplistic conceptualization of this zone.
The glacial succession in lowland Northern England
Authors: Hughes D. B. , Clarke B. G. , Money M. S. 
Published: November 2007

Abstract
The landscape of Northern England has been subjected to glacial activity several times during the Quaternary period. Successive ice sheets may have ‘swept clear’ the bedrock surface in places, but may also have incorporated materials from previous glaciations into later formations, and eventually into the present cover of glacial till. Hence, almost all the till materials now existing over Northern England were deposited during the last major ice sheet glaciation, which is known as the Late Devensian or Dimlington Stadial. These glacial tills are engineering soils, and the variable and often complex successions in which they occur have frequently led to problems on civil and mining engineering projects. Many theories have been proposed to explain the complex distribution and succession for the Late Devensian tills, which have involved the waxing and waning of the ice sheets, variations in the directions of ice flows, and other changes in the glacial and post-glacial environments. This paper attempts to summarize the published research and compare this with the authors' own experience and observations gained mainly from opencast coal mining operations in the exposed lowland coalfield areas of Cumbria, Northumberland, Tyne & Wear and County Durham. Finally, the implications for ground investigations, plus the design of stable excavations and other earthworks, are briefly discussed in the light of this experience.
Intrinsic compression and swelling properties of a glacial till
Authors: Clarke B. G. , Chen C.-C. , Aflaki E. 
Published: November 2007

Abstract
The heterogeneous tills of Northrn England and Scotland are difficult to sample and test if using standard UK site investigation practice which was primarily developed for soft to stiff sedimented clays and sands. Application of empirical correlations and theoretical models to help select design parameters that were developed from standard tests on natural and reconstituted sands and clays may not be correct for tills because of their different mode of deposition and spatial variation in particle size and type. A geotechnical model is needed to explain the behaviour of tills which includes studies of the deposition and post-depositional processes, intrinsic properties of reconstituted till, and a database of results of natural till.
Results of one-dimensional and isotropic consolidation tests on reconstituted tills, reported here, have produced compression data that define the intrinsic compression line (ICL) and a band encompassing swelling lines over a pressure range of 6 kPa to 5 MPa. The intrinsic normal compression curves for the reconstituted tills agree with the ICL, therefore developments in the application of the ICL can be applied to tills. Furthermore, a unique band, defining the intrinsic swelling properties, has potential for a baseline for the interpretation of mechanical tests on natural till.
The Cilfynydd flow slide of December 1939
Authors: Bentley S. P. , Davies M. C. R. , Gallup M. 
Published: November 2007

Abstract
This paper describes an investigation of the 1939 flow slide in colliery spoil at Cilfynydd Common, South Wales. The investigation concentrated on the geomorphological features and other aspects that were to be destroyed by a proposed reclamation scheme. The overall aim of the work was to compile a database of factual information on ground and material conditions at the flow slide site. The work involved geomorphological mapping, a site investigation which involved 18 trail pits and a detailed programme of laboratory testing including fabric analyses. The results of the study indicated distinctly different fabrics for materials from different locations in the failed mass of the landslide. In triaxial stress path tests excess pore water pressures were generated very rapidly during shearing, indicating the susceptibility of slopes formed of colliery spoil to fail by flow slide.
Algal growth on building sandstones: effects of chemical stone cleaning methods
Authors: Young M. E. , Urquhart D. C. M. 
Published: November 2007

Abstract
Biological growths including algae, lichens, bacteria, fungi and mosses are common on building sandstones wherever suitable conditions occur. Some growths, such as lichens, may be considered desirable since they can give a mature appearance to a facade, but others are often considered undesirable as they can be disfiguring and may lead to, or exacerbate, stone decay. The disfiguring of buildings and monuments by biological growths, particularly on recently cleaned buildings, is therefore a cause of some concern. Following stone cleaning, re-soiling from inorganic sources may take many years, however, re-soiling in the form of green algal growths may occur within only a few months. This paper reviews the factors which influence algal growth on building sandstone and summarizes the results of research into the effects of chemical stone cleaning with respect to algal re-growth. Results indicate that residues of some phosphate-rich stone cleaning chemicals can act as nutrients accelerating algal growth on vulnerable building sandstones.
Field and laboratory approaches to limestone weathering
Authors: Trudgill S. T. , Viles H. A. 
Published: November 2007

Abstract
Comparison of field- and laboratory-derived rates of chemical weathering is generally regarded as unsatisfactory. However, laboratory dissolution rates for calcite derived under realistic conditions which simulate the field situation compare well with field rates of measured limestone erosion, provided appropriate adjustments are made for periods of wetting. For physical and biological weathering there are far fewer field and laboratory studies available, and the range of different processes and process interactions makes comparisons difficult. However, period of wetting seems also to be a vital factor in more realistic comparisons between laboratory and field results. Experiments and field observations that look at the combined action of chemical physical and biological weathering are increasingly required.
Coastal weathering of greenschist in dated structures, South Devon, UK
Authors: Mottershead D. N. 
Published: November 2007

Abstract

Dated historic structures provide a chronological framework for the evaluation of coastal greenschist weathering over periods of up to 450 years. A weathering rate of 0.6 mm a
-1
, derived by direct methods over a short period, is shown to be valid over a span of centuries. Local variations in aspect, elevation and exposure of the structures influence weathering processes and rates. This paper is a summary of work published in full elsewhere.
Experimental production of weathering nanomorphologies on carbonate stone
Authors: Viles H. A. , Moses C. A. 
Published: November 2007

Abstract

Nanomorphological features (
c
. > 1 mm) produced by weathering processes can be observed with SEM and allied techniques. An experimental study using acidic water sprayed onto marble and calcite substrates reveals that weathering nanomorphologies can be produced and classified, and their occurrence quantified. Comparison with field samples shows that the experimentally produced nanomorphologies are smaller than, but morphologically similar to, naturally occurring features. Further experiments are needed to investigate and quantify nanomorphologies developed by a range of other weathering processes, and also to investigate their role in the development of larger-scale weathering features.
Influence of climatically induced cycles in physical weathering
Authors: Halsey D. P. , Mitchell D. J. , Dews S. J. 
Published: November 2007

Abstract
Climatically induced cycles of stone temperature and moisture content may result in physical rock weathering through various mechanisms. These mechanisms cause rock to oscillate between periods of expansion and contraction, resulting in compressive and tensile stresses. Cycles of compression and tension may cause fatigue of the stone and therefore the frequency of these cycles may be of critical importance. The temperature and moisture content of stones with four different aspects were monitored over one year and the frequency of heating-cooling, wetting-drying and freeze-thaw cycles calculated. Heating-cooling cycles were found to occur on all aspects, but the highest frequency of cycles occurred on south and west aspects during summer months. Heating and cooling of stone creates a thermal gradient within the stone, which is critical in causing insolation weathering. Differences in the rate of thermal expansion between minerals or superficially degraded parts of stone may also contribute to breakdown. Moisture availability may alter the mechanisms by which heating—cooling causes weathering. Cycles of wetting—drying are less frequent than heating—cooling cycles, but may cause weathering by five mechanisms, depending upon the hygrometric gradients. Freeze-thaw cycles show a much lower frequency than heating—cooling and wetting—drying cycles, but are active on all aspects.
Cavernous weathering in sandstone: lessons to be learned from natural exposure
Authors: Turkington A. V. 
Published: November 2007

Abstract
The most common small-scale weathering features on sandstone landscapes are caverns, widely known as ‘tafoni’. Caverning is by no means confined to one climatic regime; it is, however, especially well-developed in salt-rich environments, such as arid or coastal areas. Caverns are convergent forms created by a variety of different weathering mechanisms; salt may play a role in directly producing mechanical breakdown, or indirectly promoting chemical decay.
This study investigates the occurrence of tafoni on the Aztec sandstone in The Valley of Fire, Nevada and the Navajo sandstone in Zion National Park, Utah, USA. These Jurassic sandstones are similar: porous, fine-grained, quartzitic. The weathering features hich characterize them provide a marked contrast. Caverns are frequently developed in the Aztec sandstone; the Navajo sandstone is sparsely caverned, displaying sheer cliffs with arched hollows due to block collapse. The role of microclimatic variations in accelerated weathering in caverns is postulated, on the basis of field observations. Scanning electron microscope analysis suggests that an important control on tafoni occurrence is the lithology and structure of the rock.