bluuebunny/crossref_metadata_2025_split huggingface dataset:
Civil engineering difficulties in the karst of China
Authors: Waltham A. C. , Smart P. L. 
Published: November 2007

Karst landscapes, developed by solutional erosion of massive limestones, are characterized by underground drainage and the development of closed depressions. In tropical areas, with high solution rates, long uninterrupted periods of erosion and a lack of glacial planation, the expansion and deepening of these closed depressions creates a rugged relief dominated by either conical hills or steeper-sided towers. The form of the cones and towers is a function of both the carbonate lithology and the erosional history; the towers develop only in massive, mechanically strong, compact limestones where erosional planation and tectonic uplift have kept pace over a long period of time (
Smart et al 1986
).

These karst landscapes are characteristic of huge areas of southern China, largely in the provinces of Guangxi and Guizhou (Fig. 1) and the spectacular scenery of the limestone has often been represented in classical Chinese painting. They are now also becoming a major tourist attraction, with Guilin, in Guangxi, frequently visited by Westerners. These terrains do, however, pose serious difficulties to the civil engineer.
Where relief is not great, or where rates of uplift have been low, corridors of flatter ground have often been created by lateral planation at the water table. These corridors may be lithologically or structurally controlled, and form obvious routes through the karst.
Where the relief is higher and the regional water table is not intersected, coalescence of the depressions to form flatter ground is rare, and road and rail development is more problematic. In order to avoid excessive and
Limestone weathering: its engineering significance and a proposed classification scheme
Authors: Fookes P. G. , Hawkins A. B. 
Published: November 2007

Abstract
As a foundation material, limestone differs from other rocks in that voids may be found at almost any depth within the rock mass. They may result directly from solution weathering near the surface and along discontinuities, or as specific cave systems at depths related to present or past ground water levels.
The paper reviews the processes involved in the weathering by solution of the crystalline limestones, typically of Palaeozoic age. It offers a tentative, simple engineering classification of the solution features characteristic of limestones; and presents case histories to illustrate some of the problems which may be encountered during construction in areas of limestone bedrock.
Rock weathering in engineering time
Authors: Fookes P. G. , Gourley C. S. , Ohikere C. 
Published: November 2007

Abstract

The paper attempts a comprehensive review of
in situ
weathering of rock used in civil engineering construction. It also presents some new data on weathered rock from Britain which have been used to develop a proposed tentative Rock Durability Indicator scheme. This is based on simple engineering tests to help assess the potential performance of the rock in service.

It is concluded that weathering in geological time can have significant influence, under certain circumstances, on the durability of aggregate or stone in-service. Durability is defined as the rock material's ability to resist degradation during its working life and is considered to be dependent on a number of parameters; viz. the original stage of weathering of the rock mass; the degree of imposed stressing during winning, production, placing and service; the climatic; topographical and hydrological environments in-service.
The production and construction procedures can have an important influence on the mechanical strength of the material. Physical weathering processes and imposed loading generally have the most significant effect on deterioration but chemical weathering could be of significance in-service, especially in hot, wet climates.
No one engineering test can be used as an absolute predictor of performance. Combinations of common mechanical and physical tests such as water absorption, specific gravity, point load strength, modified AIV and magnesium sulphate soundness can be used in various combinations to help assess potential durability. For a more complete evaluation, environmental factors such as the climate, topography and hydrological regimes need to be taken into account.
Coal Measures mudrocks: composition, classification and weathering processes
Authors: Taylor R. K. 
Published: November 2007

Abstract

British Coal Measures mudrocks are dominantly non-marine, mature sediments with a high average clay minerals content of over 75%. A geological classification based on quartz content does not differentiate the dominant durable mudrocks from the non-durable types and overconsolidated clays in the formation. A uniaxial compressive strength greater than 3.6MN/m
2
with a three cycle slake durability value of over 60% is suggested as an appropriate division between durable and non-durable mudrocks of this age. Physical breakdown, which acts as a control on chemical weathering triggered by pyrite oxidation, is considered to be governed by incidence of sedimentary structures, slaking and expandable mixed-layer clay content.

Shear strength reduction during post-glacial weathering can be significant. A tentative fully weathered effective stress peak strength for the weakest mudrocks and clays is deduced to be φ′ = 22°(
c
′ = 0). Colliery tip investigations indicate that chemical weathering effects on the shear strength of the mudrocks are small. A diagenetic rank factor applies both to peak shear strength and slake durability of mudrocks excavated from UK coal mines.
Faults near Hinkley Point Nuclear Power Station
Authors: Skipp B. O. 
Published: November 2007

The Central Electricity Generating Board are seeking licence and planning approval to build a Pressurized Water Reactor just to the west of the existing Advanced Gas-Cooled Reactor at Hinkley Point, Somerset. As part of a seismic hazard evaluation both regional and local geology have had to be studied in detail.
The site is located in a complex structural setting at the eastern end of the North Somerset coastal fault belt. Detailed field mapping was carried out on the foreshore from just east of Hinkley Point to just west of Watchet with the purpose of identifying structural style, sequence of faulting and approximate age of the last movement. When assessing the seismotectonics of the region it was necessary to study the degree of middle and late stage Tertiary inversion prominent in southern England, less evident in the immediate vicinity of Hinkley Point.
Of especial interest is the north-west-south-east trending Watchet-Cothelstone-Hatch Fault and its relationship to the east-west trending faults passing close to Hinkley Point.
The Watchet Fault truncates the main east-west trending faults in the foreshore inducing a marked drag towards the fault plane, thus this phase of movement on the north-west trending fault is younger than the generally vertical displacements associated with the east-west trending faults. Examination of gypsum slickensides shows that the influence of the later movement of the north-west trending fault on reactivation of the east-west trending faults, did not extend beyond 350 m east from the main fault plane.
The fault plane of the Watchet Fault is
Aspects of geotextile-wrapped well screen design—an experimental investigation
Authors: Kennedy R. A. , Lloyd J. W. , Howley J. A. 
Published: November 2007

Geotextile screens are increasingly being used as a wrapping on a base pipe for the screening of fine aquifer materials. This is due to the ease with which they may be installed and specified. They are a relatively recent development and the hydraulic efficiency associated with their use as abstraction screens has not yet been quantified.
In this study, the efficiency has been tested using a physical well model and a variety of commercially available textiles. The purpose of the programme was to compare the hydraulic efficiency of various geotextile fabrics screening differing aquifer materials. In addition the requirements of the open area of the casing of the screens were also examined. The results of the tests indicate that geotextiles must be matched to aquifer material on the basis of hydraulic efficiency. It is clear that the presence of aquifer particles reduces the permeability of any screen and this is also true in the case of geotextile-wrapped screens. The extent of this reduction varies between geotextiles and appears to be a function of their structure. On the basis of the test results, recommendations may be made for geotextile selection. Geotextile screens appear to be particularly suited to the screening of fine unconsolidated aquifers if the correct fabric is selected. Losses incurred from the screening of other coarser aquifers also appear to be negligible. Too conservative a filter criterion may result in unnecessary well losses. The open area of casing used as part of geotextile screens installed in fine sands may be as low as 300025; without incurring significant losses.
The location of aquifers in crystalline rocks and alluvium in Northern Nigeria using combined electromagnetic and resistivity techniques
Authors: Hazell J. R. T. , Cratchley C. R. , Preston A. M. 
Published: November 2007

The tenfold increase in borehole siting in Northern Nigeria during the last few years has resulted in an increase in the use of electromagnetic (EM) methods and a corresponding decrease in the more traditional but less cost effective resistivity methods. The role of geophysics in exploration is optimally in combination with direct geological observation. Two types of aquifer which are amenable to geophysical investigation in the Nigerian environment are weathered, jointed crystalline rocks and alluvium.
Location of joints and associated narrow zones of deep weathering in crystalline terrain is best achieved by EM techniques with resistivity backup where needed. Resistivity alone does not always reveal such features. Location of shallow aquifers in alluvium is amenable to a combination of EM and resistivity techniques. However, the complexities of alluvial and underlying Quaternary sedimentation necessitate extensive computer modelling of both sets of data in order to optimize the field techniques and interpretation methods. In particular the use of selected combinations of intercoil spacings to estimate maximum thicknesses of aquifers shows some promise.
Changing storage beneath a stationary water table—an anomaly of certain humified peats
Authors: Brown J. M. B. , Ingram H. A. P. 
Published: November 2007

Abstract
Previously published seepage tube test results for well-humified peats at Dun Moss showed anomalous water transmission properties only partially explained by non-Darcian behaviour found in permeameter tests. In a new suite of seepage tube recovery tests it was found that the shape of the recovery curve varied with the time taken to establish the initial displacement. This variation, which is not associated with any movement of the water table, suggests that these peats possess a pressure-sensitive storage property consistent with the elastic behaviour of a wide range of aquifer materials of current interest to hydrogeologists. This interpretation is supported by comparison with the hydrogeological ‘slug test’ and by results from a special ‘re-fill’ variant of a recovery slug test. In these tests the water level was observed to decline spontaneously while below the equilibrium level, an effect explicable only by exchanges to storage.
Some geological and engineering characteristics of lodgement tills from the Vale of St Albans, Hertfordshire
Authors: Little J. A. , Atkinson J. H. 
Published: November 2007

This paper gives the results of mineralogical and engineering classification tests and one-dimensional consolidation and swelling tests on undisturbed and reconstituted samples of a number of different lodgement tills from the Vale of St Albans in Hertfordshire. These tills are presumed to be of Anglian age and mark the approximate southernmost Quaternary ice advance in the area. They are interbedded with fluvioglacial sands and gravels which were deposited on the proglacial fringe of a retreating ice mass, and other sands and gravels which are associated with a former course of the Thames in the Vale. In mineralogical tests the tills were found to contain crystalline calcite; this could lead to cementing in undisturbed samples which would be broken down during preparation of reconstituted samples.
The results of oedometer tests show little evidence of compression or consolidation anisotropy in clast fabric orientated, undisturbed samples. Differences in the compression and swelling characteristics of undisturbed and reconstituted samples attributable to calcite cementing were observed, particularly at the lowest consolidation pressures during initial loading. Differences in permeability between the undisturbed and reconstituted samples were also found to be greatest at the lowest consolidation pressures during initial loading. Examination of the swelling characteristics revealed a marked threshold effect shown by significant variations in the swelling index associated with changes from loading to unloading and from swelling to reloading.
Seismic refraction profiling of rockhead in the Coal Measures of northern England
Authors: Brabham P. J. , Goulty N. R. 
Published: November 2007

The seismic refraction method using compressional waves has been used in site investigation for many years to locate rockhead. Results from several surveys in northern England, where Quaternary glacial drift overlies Coal Measures, show that shear waves exhibit a large positive contrast in seismic velocity between overburden and bedrock, whereas the ranges of seismic velocity of compressional waves in overburden and bedrock are not clearly separated. Consequently, shear wave velocity is a more reliable indicator of lithology, and seismic refraction profiling using shear waves may be a better technique for estimating the depth of rockhead.
Unusually low compressional wave velocities have been measured over abandoned mine workings. If this is a subsidence effect, it may prove useful for locating old mine workings.
Shear strength and consolidation characteristics of Obhor sabkha, Saudi Arabia
Authors: Hossain D. , Ali K. M. 
Published: November 2007

The shear strength and consolidation characteristics of the subsoil of Obhor sabkha (north of Jeddah, Saudi Arabia) are critically reviewed. The problems of assessment and the practical implications are discussed.
Aging, desiccation, cementation and groundwater table changes appear to have contributed to the observed variation in the properties of the lightly overconsolidated soft grey, sensitive, silty clay covering the landward two-thirds of the sabkha. The overconsolidation of the underlying stiff, brown, sandy silty clay is considered to be due to desiccation and erosion followed by a rise in sea-level during the last transgression of the Red Sea.
Field vane tests sometimes show locally high undrained shear strength in the soft clay due to interference by large gypsum crystals or marine shells, both of which also cause difficulty in sampling and specimen preparation. The nature and the thickness of the uppermost soil units, the position of groundwater table and the chemical nature of the environment in the different parts of the sabkha are shown to be an important consideration influencing the selection of appropriate types of foundation and any requirements for soil improvement.
Microseismic techniques for monitoring incipient hazardous collapse conditions above abandoned limestone mines
Authors: Miller A. , Richards J. A. , McCann D. M. , Browittt C. W. A. , Jackson P. D. 
Published: November 2007

Abstract
The progressive collapse of abandoned limestone mines over many decades has led to problems of general subsidence and crown-hole formation in parts of the West Midlands. The substantial size and extent of the voids makes the cost of infilling all of the mines prohibitively expensive, at least in the short term. One option is to monitor the workings to identify active areas and assess the rate of collapse. This would provide government and local authorities with additional criteria for establishing priorities for remedial action. Monitoring of the condition of the mines is made difficult by their general inaccessibility, but it was thought that the detection of microseismic energy associated with rock failures and roof-falls might provide a useful method of remote monitoring.
This paper summarizes a series of studies designed to develop and field test a method of monitoring microseismic events and discriminating them from the many other seismic sources. Experiments involving simulated roof-falls in an accessible (air-filled) mine indicated that the most detectable source of seismic energy is generated by debris impacting on the mine floor, rather than by stress-induced rock failure. Consequently, the energy is in a lower frequency range (around 10 to 300 Hz), than was at first anticipated.
Trials using both continuous and triggered recording, with a variety of transducers, installation techniques and network configurations, provided useful information regarding optimum network design for the discrimination of roof-falls. On the basis of these findings a seismic network was successfully implemented to monitor roof-falls during a mine infill trial. Finally, an experimental network of instruments in boreholes at a water-filled mine demonstrated, by means of artificial seismic sources, that the technique can also be applied to flooded, inaccessible mines.
A revision of the description and classification of weathered granite and its application to granites in Korea
Authors: Lee S. G. , de Freitas M. H. 
Published: November 2007

Abstract
This paper reviews commonly occurring difficulties associated with the description and classification of granite and proposes revised schemes for this purpose. The schemes can be applied to granitic material and granitic masses, the revised scheme for describing the latter incorporating the new criteria of volumetric percentage of weathering grades to define weathering zones. Examples are provided of the application of these revised schemes to granites in Korea.
The relative density of geologically aged, British fine and fine-medium sands
Authors: Barton M. E. , Palmer S. N. 
Published: November 2007

Abstract

Values of relative density (
D
r
) have been measured on 20 samples of uneemented, virtually matrix-free, fine and fine-medium quartzose sands ranging in age from Recent to Jurassic. For all except Recent and younger Pleistocene sands, which were impregnated
in situ
, the
in situ
dry density (ρ
d
) was measured on intact, block samples. A single method was used for
ρ
d
min (Kolbuszewski's tilting method) and three methods for ρ
d max
: namely the vibrating hammer procedures of Kolbuszewski, B. S. 1377 Test 14 and slow pouring.

A general trend of increasing
D
r
with geological age was given by all the methods used for determining ρ
d max
. Even with the Kolbuszewski method, values of
D
r
> 100% were obtained on some of the sands: a maximum of 1120eing recorded on the Grantham Sand of Jurassic age. Values of
D
r
using the B.S. 1377 procedure ranged between 23 and 57 0.000000or the Recent and Pleistocene sands and between 90 and 122 0.000000or the Tertiary and Mesozoic sands. The ease of the slow pouring method for ρ
d max
recommends it as a potentially useful diagnostic test to determine the degree of locking in geologically aged sands.
Soluble salt damage to thin bituminous road and runway surfaces
Authors: Obika B. , Freer-Hewish R. J. , Fookes P. G. 
Published: November 2007

Abstract
The paper reviews current knowledge of damage by soluble salts to thin bituminous highway and runway surfacings in warm climates. It critically examines the various recommended maximum salt limits for materials in highway construction and reviews preventative and remedial practices.
The study included a laboratory simulation of salt damage using climatic cabinets to identify the cause of salt damage to thin bituminous surfacing of a runway in the West Indies.
The work shows the importance of linking relationships and influences of geology, hydrogeology and construction practice with material and salt types, migration and crystallization pressures, crystal properties, hydration/dehydration and climate in order to prevent damage occurring.
The examination of encrustations in an unlined borehole using the sidewall sampling technique
Authors: Howsam P. , Brassington F. C. , Lucey P. A. 
Published: November 2007

Abstract
In borehole rehabilitation, engineers usually have limited access to information about the borehole condition and the processes involved. This paper describes the use of the sidewall sampling technique to gain information about some manganese encrustations which are considered to be adversely affecting the yield of a large-diameter, unlined, Triassic sandstone borehole in NW England. Trials with the technique proved successful and suggest that it is worth considering in any rehabilitation feasibility or implementation projects in which similar conditions prevail.
Nomograms for the analysis of recovery tests on large-diameter wells
Authors: Barker J. A. , Herbert R. 
Published: November 2007

Abstract
A set of nomograms has been constructed to facilitate the application of the solution of Papadopulos & Cooper to recovery tests on fully-penetrating large-diameter wells in confined aquifers. The data required are: the well geometry, the abstraction rate and period, the drawdown at the end of pumping and the time taken for 25, 50 or 75% recovery to occur.
Large Byzantine water storage cisterns
Authors: Lerner D. 
Published: November 2007

At least 36 cisterns, excavated reservoirs, were constructed in Istanbul during Byzantine times. The largest known covered cistern is the Basilica cistern which was probably completed in the early 6th century. Figure 1 shows a plan view of the 140 × 70 m structure, which now lies partly under a road in a busy area of Istanbul. It was originally supplied by aqueduct from springs in Marmara, west of the city. Figure2 gives a general view of the interior, where the roof is supported by 336 columns.
Figure 3 shows the base of one of the column which appears to be made from a scrap sculpture of the Medusa's head. There are constant inflows of water at various points in the roof of the cistern, as can be seen from the pool of water, splashes and drips. At the time the photograph was taken in March 1988, it had not rained for at least 15 days, hence the inflow could not have been direct recharge. The water was clear and odour-free and was certainly not sewage. The probable source was leaking water mains which, without the cistern, would percolate to the water table. Thus Figure 3 provides some evidence that leaking mains recharge groundwater as argued in recent articles (Lerner 1986, 1988a, b).
My thanks to Professor Okay Eroskay of Istanbul University for help with the photography.