bluuebunny/crossref_metadata_2025_split huggingface dataset:
A re-evaluation of well design procedures
Authors: Parsons S. B. 
Published: November 2007

Abstract
The development of appropriate design procedures for water wells is a subject that has evolved only slowly over the years. Guidelines quoted in most groundwater engineering textbooks are largely empirical and focus on the provision of reliable wells that produce the intended yield with as small a drawdown as possible. The principle of developing designs that minimize the overall cost of the well installation, including the cost of energy used in pumping, is not really addressed. A critical review is presented of established design procedures, and techniques that have been developed for quantifying the energy potentially lost within alternative well designs. Following this review, methods which are more physically realistic and reliable are identified to calculate the key energy loss components of screen upflow losses and partial penetration losses. This, in turn, leads to the development of a way of identifying the costs associated with pumping as a function of the design of the well (most notably the well screen length), which can be used to optimize well design. A comprehensive set of well design guidelines is thereby developed.
The groundwater hydrology of the Manga Grasslands, northeast Nigeria: importance to agricultural development strategy of the area
Authors: Carter R. C. 
Published: November 2007

Abstract
The Manga Grasslands of northern Nigeria/southern Niger form a unique landscape of dunefields and interdunal depressions (playas or oases) within the semi-arid southern Sahel. Little has been written previously about the hydrogeology of the region, despite the importance of water resources to the existing agricultural and evaporite mineral economy. The paper reports on preliminary investigations into the groundwater hydrology of the area and proposes a simple steady-state conceptual model of groundwater recharge and natural outflow. It is concluded that the development of pumped irrigation in the vicinity of the oases would be unwise in view of its likely short- and long-term effects on groundwater levels, and the consequent damage to the existing economy which would result.
Three-dimensional ground movements in the vicinity of a mining activated geological fault
Authors: Phillips K. A. S. , Hellewell E. G. 
Published: November 2007

Abstract
This paper investigates the circumstances and conditions that lead to the activation of a particular geological fault when longwall panel extraction occurs in the vicinity.

Three-dimensional ground movements were observed at survey stations located across a fault as these were being influenced by active mining. The development of ground movements is defined be recording the subsidence, strain and horizontal displacements of the survey stations. The measured ground movements are compared to the predicted
Subsidence Engineer's Handbook
and in-house Subsidence Prediction Program subsidence and strain profiles, and the visual damage evident along the testline. Conclusions are drawn which suggest that surface geology heavily influences the location and magnitude of sustained surface damage.
Analysis of residual subsidence movements in the UK coalfields
Authors: Yao X. L. , Reddish D. J. 
Published: November 2007

Abstract
The importance of residual subsidence in the study of ground movement due to mining is discussed and previous research results are briefly reviewed. On the basis of ten cases investigated within the UK coalfields, the difference between residual subsidence characteristics along longitudinal and transverse lines is studied. Particular attention is paid to the four key positions along the subsidence profile, i.e. the subsidence limit position, the half-subsidence position, the rib-side position and the central position. A case example associated with mining an inclined seam is investigated in detail, showing that different residual subsidence characteristics appear due to mining an inclined seam as opposed to a level seam. Additionally, a prediction model is presented and applied to determine the duration of residual subsidence. The model theoretically indicates the main factors controlling the period of residual subsidence. Finally, an empirical equation, based on data collected within the UK coalfields, for estimating the duration of residual subsidence is put forward with consideration of both depth and geological factors. This is believed to be an important tool for civil engineers to calculate the time span after which no precautions need be taken to protect surface buildings from further damage due to residual subsidence movements.
The influence of petrology and fabric on the engineering properties of concretionary laterite gravel aggregates
Authors: Akpokodje E. G. , Hudec P. P. 
Published: November 2007

Abstract
The probable field performance of concretionary gravel aggregates is difficult to predict in the tropics, mainly due to the lack of understanding of the factors that control their engineering properties. The mineralogy and fabric of commonly used laterite gravel aggregates in Nigeria were studied to assess their influence on the engineering properties. Thin- section studies revealed two characteristic features which greatly influence the physico-mechanical properties: (a) abundant voids and fissures of different sizes and (b) varying degree of iron oxide impregnation. The variations in these characteristics are due to differences in the degree of lateritization. Strong and well developed gravels and pisolites are composed of 65–95 0oethite/hematite and are dominated by small voids. Weak and immature laterite gravels contain much larger pores and greater amounts of quartz and kaolinite. The quartz grains show extensive cracking which futther reduces the mechanical strength of these laterite gravels. The void/fracture-dominated fabric of laterite gravel aggregates is mainly responsible for their unusually high absorption/porosity and relatively low strength. In some laterite gravels, the strength loss on wetting is mainly due to weak cementation and the presence of interstitial clays.
Effect of suction on the strength of rock
Authors: West Graham 
Published: November 2007

Abstract
Some existing experimental data on the uniaxial compressive strength of porous rocks have been re-examined in relation to the suction of the specimens. It is shown that from pF 0 to pF 5 the rock strength is little affected but from pF 5 to pF 7 the strength depends markedly on suction. It is suggested that at low moisture contents, suction contributes to rock strength in a similar way to its well known contribution to soil strength.
Techniques used in aggregate resource analyses of four areas in the UK
Authors: Crimes T. P. , Chester D. K. , Hunt N. C. , Lucas G. R. , Mussett A. E. , Thomas G. S. P. , Thompson A. 
Published: November 2007

Abstract
Techniques used in four major sand and gravel resource analyses in the UK are described. For each survey, an archive of pre-existing borehole data was assembled. Borehole distribution may be uneven and, in glaciated terrains, they may be concentrated in the valleys and absent from positive geomorphological features, which might represent the major resources. Satellite imagery may be useful for assessment of coastal resources and was also used to illustrate the environmental context of deposits but it is unreliable as a predictive tool in the UK. Geomorphological surveys provided a rapid cost-effective method for identifying potential resources, particularly in glaciated terrains with prominent landforms. Geophysical techniques were less successful. Seismic surveying was expensive and did not provide consistently accurate results. Resistivity surveys were used and an experiment was devised to assess their accuracy. For this, detailed logs were provided for ten boreholes to allow on-site instrument calibration, then another ten borehole locations were given but without geological data. Resistivity estimates at the latter borehole locations overestimated overburden by 39% and depth to bedrock by 340ut underestimated mineral thickness by 29%. Hydrogeological data were collected as part of the data bases and gave a broad indication of likely groundwater conditions existing in most resource areas. Resource criteria used in previous IMAU assessments are considered insufficiently stringent and, in particular, an upper limit for mineral of 40 0.000000ines is considered too high and a reduction to 20uggested. This would significantly reduce the volumes of some previously estimated resources. Within the areas surveyed here, the reduction in mineral volume would vary from 5 0n the Lleyn to 77 0n Harbury-Kineton. Planning analyses have been undertaken as part of three of these surveys and provide useful information on likely constraints to exploitation but they must avoid compromising the County Councils in their role as Minerals Planning Authorities. Techniques of data presentation are crucial to success in reaching a wider audience and the usefulness of three-dimensional diagrams is indicated.
Discussion on ‘The significance of faults for the Afulilo hydro scheme in Upolo, Western Samoa’ by H.J. Gudge & A. B. Hawkins
Authors: Gudge H. J. , Hawkins A. B. 
Published: November 2007

P. M. JAMES and D. J. PAUL write: In their paper, the authors give a useful background appraisal of the Upolo and raise a number of geotechnical issues on the Afulilo scheme. However, the authors base their knowledge on the very preliminary investigations gathered during the feasibility study for the hydro-power scheme, which terminated in 1986. Since that time extensive investigations and new studies have been undertaken for the design of the scheme by Lahmeyer International (Germany) and Kinhill Cameron McNamara (Australia) (Consortium Lahmeyer International & Cameron McNamara 1988). Prior to design and construction the following activities, among others, were performed in the years 1987 and 1988:

12 core drillings totalling 375.7 m,

11 seismic traverses of 3.15 km in length,

8 geological profiles, 459 m long in total,

18 auger drillings, and

40 test pits.

The project is now well into the construction phase and the writers, who were involved in these additional studies, are replying to the authors' paper on behalf of the Consultants' consortium.
In order to answer some of the specific concerns raised by the authors, a brief and updated geological description of the Afulilo Project is given.
Active ground fissures in Xi'an, China
Authors: Forster A. 
Published: November 2007

Once the ancient capital of China (Chang'an) and currently known worldwide as the home of the Terracotta Army, Xi'an is an important, modern, industrial centre of northwest China with steel, textile, chemical and machinery factories and a population of over 2.5 million. It lies on the River Weihe, approximately 1100 km southwest of Beijing in the Province of Shaanxi, of which it is the capital (Fig. 1). The surrounding valley is intensively farmed and is one of the main growing areas of northwest China. Climatically the area is part of humid and sub-humid, warm, temperate, north China.
Several major crustal faults occur in the Xi'an area and form a fault-bounded, depositional basin of Early Tertiary age on the southwest part of the Huabei plate. The latest fill comprises up to 700 m of fluvial, lacustrine and loessic deposits of Late Tertiary to Recent age. There are three distinct river terraces on the broad flood plain of the River Weihe and additional terraces on the foot slopes of the Qinling Dabie Mountains which form the southern margin of the valley. On the hills surrounding the valley, to the north and south, there are fine grained, clayey, loess deposits of Late Pleistocene age lying on Middle Pleistocene loess. The main loess deposits are found to the north on the loess plain whose southern margin forms the northern boundary of the valley.
The area is tectonically active and extension of the Xi'an region has resulted in the formation of a number of active
Groundwater in Scotland and Northern Ireland: similarities and differences
Authors: Robins N. S. 
Published: November 2007

Abstract
Groundwater contributes only a small amount of raw water to public supply in Scotland and Northern Ireland, but it is nevertheless an important resource and is often the only reliable and potable source for rural communities. There is a striking similarity between the geology and structure of lowland Scotland and that of Northern Ireland due to the southwesterly continuation of the Midland Valley graben into Ireland. That similarity is not widely reflected in the hydrogeological conditions encountered in the bedrock aquifers on either side of the North Channel. Groundwater in both Scotland and Northern Ireland is under-utilized except in some isolated aquifer units where demand now warrants formal groundwater management. Knowledge of most of the major groundwater units, in particular of recharge and recharge processes, is not, as yet, sufficient to create operational models on which to base a system of abstraction licensing.
Description of moisture content in soil profiling
Authors: Schreiner H. D. , Gourley C. S. 
Published: November 2007

Abstract

The description of moisture content in soils during soil profiling generally follows the scale devised by Jennings
et al.
Another guide, published as part of the Engineering Group Working Party Report on Tropical Residual Soils, provides some diagnostic characteristics for determining soil moisture categories. However, neither of these systems is fully satisfactory since much is left to subjective judgement. This Technical Note describes a more comprehensive method of description which includes diagnostic characteristics such as stickiness, dustiness, resistance to moulding, strength changes and colour changes and which also clarifies the relation of the terms to the optimum moisture content. This guidance should assist in making the field description of moisture content in soils less subjective.
Rock weathering descriptions: current difficulties
Authors: Cragg D. J. , Ingman J. 
Published: November 2007

Abstract
The guidance given in BS5930:1981 for rock weathering descriptions at the material scale is considered to be inappropriate for UK practice, and is seldom applied to rock core logging. Practitioners turn to alternative weathering schemes for logging rock cores, some of which are inappropriate at the material scale; others are intended for specific, uniform lithologies and may also prove to be unsuitable when geological conditions vary from the presumed uniformity. The authors present examples from various geological situations, to demonstrate the difficulties arising when existing published weathering schemes are applied. The difficulties associated with deriving mass zonations from material scale descriptions are considered. The description of cores at the material scale is considered to require quantified detail, independent of the prescribed schemes currently existing.
Site assessment and characterization for high-level nuclear waste disposal: results from the Stripa Project, Sweden
Authors: Olsson O. , Gale J. E. 
Published: November 2007

Abstract
The Stripa Project, on geologicaldisposal of radioactive waste, has been completed after a 15-year cooperative international research effort. This article summarizesthe results of research and development on methods to characterize the flow and transport properties of a fractured rock mass for repository site evaluation. The approach used, and the flow and transport experiments conducted, provide new data and permit a comparison ofmodel predictionswith large-scalefieldmeasurements. The 3D discrete fracture models used in this research gave good predictions of flowand transport to sinkscreated by boreholesbut werenot ableadequatelyto representexcavation induced changes to drift inflows.
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

Abstract
Karstic features such as swallow holes and dolines are the rule rather than the exception in the Chalk outcrop of southern England, particularly in the region of the Chalk/Tertiary boundary. Previous tracer tests at Bedhampton and Water End have indicated groundwater transport velocities of 2.2 and 5.5km/day. A recent tracer test at Stanford Dingley in Berkshire has indicated comparably high transport velocities in the Chalk: 5.8km/day for peak tracer concentration, and 6.8km/day for tracer breakthrough. In all three cases the swallow hole systems were able to transmit turbid surface run-off contamination over large distances, indicating a short-circuiting of the natural attenuating properties of the unsaturated and saturated zones. In the light of this, the practice of using swallow holes to dispose of agricultural- and road-run-off should be discouraged.
Hydrogeochemistry of minewaters flowing from abandoned coal workings in County Durham
Authors: Younger P. L. 
Published: November 2007

Abstract
Although all deep mining has now ceased in the Durham coalfield of northern England, dewatering still continues (in June 1995) in the central area of the Coal Measures outcrop.Beyond the radius of influence of the dewatering pumps, the water table has already recovered, and several uncontrolled minewater discharges are found. These waters are moderately mineralized(total dissolved solids in the range 600 to 2500mg/1) and may have appreciable alkalinity. Iron loadings are typically high and give rise to thick ochre deposits on streambeds. White deposits are associated with high aluminium concentrations. Sulphate occurs in the range 130–1300mg/1, but in the receiving waters downstream from discharge points reductions in sulphate concentration are observed. Preliminary hydrochemical modelling results suggest that these observed reductions are explicable by precipitation of iron sulphates (e.g.jarosite). Existing hydrochemical classification schemesinadequately characterize these waters; therefore a new scheme is proposed which should be applicable in many areas with similar geology. Immediate practical use of the results presented here lies in predicting possible future river pollution if dewatering ends, and planning for abatement of such pollution using constructed wetland technology.
Observations on soil permeability, moulding moisture content and dry density relationships
Authors: Wright S. P. , Walden P. J. , Sangha C. M. , Langdon N. J. 
Published: November 2007

Abstract
Increasing use of the coefficient of permeability as a quality control parameter for earthworks, in particular for landfilling, has resulted in many engineers looking to predict coefficientsof permeability for clays from more widely available but often widely scattered data. In a number of cases this has led erroneously to the interpretation of the moisture content coefficient of permeability relationship as the direct inverse of the moisture content-density relationship. This paper re-examines the original theories proposed for movement of water through soils of differing grain size and goes on to show that extrapolation of the permeability-density relationship for granular soils to finer grained soils is incorrect. Laboratory permeability tests were conducted on four different soil types using the falling head permeameter to investigate the relationships between permeability, dry density and moulding moisture content for each soil. Coefficients of permeability were determined for moisture contents up to the liquid limit of the soil. It is shown that a minimum value of permeability is obtained close to optimum moisture content and that this is maintained to within sensible engineering limits for moisture contents up to that of the liquid limit. Results obtained for predominantly granular soils confirm that permeability is a function of density but, for more cohesive soils, permeability is unaffected by changes in moisture content wet of optimum. Conclusions emphasise that to achieve minimum possible coefficients of permeabilitythere is a need for soilwater content at placement to be at or slightly above optimum moisture content and for pelletization of clay material.
The role of lime migration in lime pile stabilization of slopes
Authors: Rogers C. D. F. , Glendinning S. 
Published: November 2007

Abstract
Lime piles, which essentially consist of holes in the ground filled with lime, have been successfully used worldwide for the in situ treatment of failing clay slopes. The literature on the technique does not, however, permit a full explanation as to why lime piles work or how to design them. It is widely reported that migration of the lime from the piles into the surrounding clay provides the major stabilizing mechanism. This paper aims to review the literature on lime migration from piles and to report the results of recent research at Loughborough University to determine migration mechanisms from compacted quicklime piles. Potential applications are then discussed in the light of the findings.

Hydroxyl (OH
-
) ion migration by diffusion processes in intact clay is shown to be limited by high reactivity to approximately 20-30 mm. Nevertheless hydraulic transport via dehydration cracking or other discontinuities in the clay mass could result in migration extending for far greater distances. Calcium (Ca
2+
) ion migration, would be expected to occur over distances greater than 1 m in ten years. Thus while full clay stabilization might only occur to a limited degree, modification of the clay is likely to be widespread. Mineralogical changes indicate a strength gain equivalent to that of lime mixed with clay at the initial lime consumption (Eades & Grim 1966) value plus 2% and cured for 28 days.
Assessment of the quality of building stones using signal processing procedures
Authors: Valdeon Luis , de Freitas M. H. , King M. S. 
Published: November 2007

Abstract
A combination of spectral and velocity analysis, using an ultrasonic pulse technique, has been performed on two lithologies of building stone: limestone and sandstone. Measurements of compressional and shear wave velocities have been made and the results obtained compared with the data provided from analyses of the frequency spectra so obtained from these rocks. It appears that the centre frequency and attenuation calculated from the frequency spectra provide useful quantitative measures of rock quality which augments that obtained from measurements of velocity alone, especially in saturated specimens. The potential value of using the centre frequency and attenuation as references to study the progressive change of rock quality during weathering has yet to be assessed.