bluuebunny/crossref_metadata_2025_split huggingface dataset:
Critical state parameters and peak stress envelopes for Bangkok Clays
Authors: Balasubramaniam A. S. , Zue-Ming Hwang , Uddin Waheed , Chaudhry A. R. , Li Y. G. 
Published: November 2007

Summary

This paper is concerned with a detailed study of the critical state parameters and peak stress envelopes for undisturbed samples of Bangkok Clays (‘Weathered Clay’, ‘Soft Clay’ and ‘Stiff Clay’) taken from a site called Bangpli which is about 28 km from Bangkok. Both triaxial compression and extension tests were carried out with a wide variety of applied stress paths in a manner similar to that adopted by
Parry (1960)
. For all types of tests the end points are presented in (
q, p
), (
w
, log
p
) and (
w
, log
q
) plots;
q
is the deviator stress,
p
is the mean normal effective stress and w is the water content. The Mohr Coulomb strength parameters are also evaluated for each series of tests. The results are discussed in relation to the critical state concept of
Roscoe et al. (1958)
and the water content-strength relationships of
Henkel (1959)
.
Preliminary evaluation of the groundwater resources of the western part of the Vale of Pickering
Authors: Reeves M. J. , Parry E. L. , Richardson G. 
Published: November 2007

Summary
An investigation of the water resources of the fissured limestone/sandstone Corallian Series aquifer was carried out between 1970 and 1974. The techniques employed and the interpretation of flow mechanisms and development potential may be relevant to other similar areas of the United Kingdom as well as further afield. Groundwater movement and chemistry are shown to be strongly related to geological structure. The aquifer is characterized by a relatively high recharge rate and, in some zones, high transmissivity; storage is very limited. This latter characteristic leads to difficulties in the formulation of development proposals, particularly if the aquifer is to be employed in river regulation.
Discussion on ‘The analysis and planning of step drawndown test’ by
Authors: Milne-Home W. A. 
Published: November 2007

Dr Clark has presented an excellent review of the theory of the step drawdown test and its applications. The purpose of this communication is to comment on the use of the recovery portion of a step drawdown test to calculate aquifer transmissivity. The Theis method may be applied if the variable discharge rate is replaced by the average of the pumping rates. This average may be expressed as:
where Q̄ = mean pumping rate, V = total volume pumped, t = total pumping time.
Equation (1) is equivalent to Clark's formulation. Although it is a useful working approximation, more accurate results would be obtained if Q̄ were calculated by weighting each discharge rate by the time elapsed since that rate began. Sternberg (1967) has described such a method which can be modified slightly to determine transmissivity from the recovery portion of a step drawdown test. The transmissivity T, of an infinite, confined aquifer is shown to be:

where t
e
= 2{t-(ʃ10Q(γ)γ dγ /V)}, γ = time from start of pumping to time t, ť = time since pumping stopped, Q
e
= V/t,
e
, Q(γ) = variable pumping rate, sW' = residual drawdown in the pumped well (replacing the residual drawdown at any point radially distant r from the well in Sternberg's derivation).

For short step drawdown tests with steps of equal length, t
c
may be approximated by: where n = number of steps, Δt = length of each step, t
e
= time intervals since pumping started, Q
ti
+
ti+1
=
Ground water quality in weathered Deccan Basalt of Malwa Plateau, India
Authors: Lunkad S. K. , Raymahashay B. C. 
Published: November 2007

Summary
Selected samples of well and spring waters from the weathered profiles of a typical Deccan Basalt outcrop reveal strong controls of soil mineralogy. Calcium plagioclase, augite and volcanic glass in the bed rock weather to montmorilloniterich black soils in the foothills. Soils at higher slopes are lateritic. Lime concretions are common and quartz is ubiquitous.

The HCO
3
/SiO
2
mole ratio in the waters is in the range predicted for alteration of plagioclase to montmorillonite and augite to kaolinite. The silica level is above quartz solubility and generally below solubility of amorphous silica. Montmorillonite and calcite are thermodynamically stable in the ground water environment. Geochemical mobility of elements during weathering decreases in the order Na, Mg, Ca, K, Si and Fe.
Discussion on ‘Drift deposit influences on the Triassic Sandstone aquifer of NW Lancashire as inferred by hydrochemistry’ by
Authors: Worthington P. F. 
Published: November 2007

The authors are to be congratulated on this interesting paper, the implications of which extend beyond purely local considerations. The evident agreement between the hydrochemical data and the earlier geophysical interpretation of the glacial sands (Worthington 1972) supports the integrated use of these diverse techniques in hydrogeological evaluation. Although surface geophysical methods are well proven, they are not universally regarded as established within the framework of hydrogeological practice. If this paper encourages a more general acceptance of hydrogeophysics, it will have served an additional useful purpose.
One or two specific points do call for comment. The statement ‘Worthington (1977) records that the aquifer has a predominant intergranular permeability’ is not strictly correct and it therefore seems somewhat inappropriate to label the alleged proposition as ‘contentious’. The basic assertion of the paper cited is immediately evident from the abstract:
‘... the intergranular component of groundwater flow (within the Triassic Sandstone) can vary markedly from place to place and is apparently the predominant mechanism within a sizable area. Elsewhere intergranular flow is supplemented by fissure drainage, and is sometimes relatively insignificant. It is concluded that intergranular permeability exerts a basic control upon abstraction well productivity, with maximum benefits being derived where a comparatively strong intergranular flow is augmented by a well-developed, localized fissure network’.
The major point to emerge here is that it is intergranular permeability which appears to exert a fundamental control upon the hydraulic conductivity of the Triassic Sandstone. It is therefore especiallv encouraging to note the agreement between,
A proposal for quantitative terrain evaluation for highway construction
Authors: Rodriguez Ortiz J. M. , Prieto C. 
Published: November 2007

Summary
From the analysis of several highway projects throughout Spain the relative importance of various engineering geological factors have been evaluated. The following relevant factors are selected: bearing capacity, slope stability, quality of borrow material, problems of excavation, geomorphology, climatic conditions, and drainage conditions.
These factors are combined to define a feasibility index ranging from 0 to 2, evaluating the terrain according to its suitability for new highway projects, indicating the intensity and type of problems which can be expected. The evaluation is usually represented on maps at a scale of 1:25 000.
Remote sensing for the location and mapping of engineering construction materials in developing countries
Authors: Beaumont T. E. 
Published: November 2007

Summary
Multispectral satellite imagery and other remote sensing techniques may now be employed to carry out surveys over large land areas so that fuller use can be made of locally available materials in order to reduce the costs of road construction. In many developing countries local resources are often not used as extensively as would be possible, due to the adaptation of specifications for road building materials that have been derived in industrialized countries with temperate climates and different geology.
These specifications are often inappropriate for natural gravels, weathered rock, and concretionary materials found in the tropics, many of which can be used successfully for constructing lightly-trafficked roads. The value of using recent technological developments in remote sensing methods and techniques of image analysis to locate and map the occurrence of such indigenous engineering materials are discussed with reference to a survey undertaken in Botswana to locate calcrete for low-cost road construction in the Kalahari Desert.
The littoral sediment budget between Selsey Bill and Gilkicker Point, and its relevance to coast protection works on Hayling Island
Authors: Harlow D. A. 
Published: November 2007

Summary
The sediment distribution pattern on the beach and near-shore seabed has been established with the aid of a sampling programme and diving inspection. The littoral sediment budget has been established and quantified for the coastal unit, and a method of estimating historical rates of littoral drift from coastal changes has been developed. The effect of sediment reservoirs in regulating the budget, and the effect of dredging has also been considered.
Neither groynes nor seawalls have entirely succeeded in preventing erosion on Hayling Island, where the basic problem is a reducing feed of beach material to maintain the littoral drift. Beach replenishment proposals conclude the paper.
The contribution made to cliff instability by Head deposits in the west Dorset coastal area
Authors: Conway B. W. 
Published: November 2007

Summary
In the west Dorset coastal area superficial materials include Head deposits which, by the nature of their origin, are variable in structure and composition. Two broad types are recognized depending on the provenance of the predominant constituent: Cretaceous Head and Lias Head. The Cretaceous Head was probably formed near to or at the end of the Devensian stage of the Late Pleistocene. Where the two types of Head deposit are superimposed, Cretaceous Head always lies above Lias Head.
On many slopes Lias Head has topographic expression as lobate sheet forms which are frequently masked by a blanket of Cretaceous Head. The high permeability of Cretaceous Head together with the low strength of Lias Head produce slopes presenting potentially unstable conditions to depths of up to 4 m below ground surface.
Three minor types of instability are generated in the Head deposits themselves: shallow translational movements, block slides, and shallow rotational slides. In addition, the high permeability of Cretaceous Head permits water to be introduced to undercliff areas, thus facilitating the development of instabilities in the solid formations below. This results in a mechanism of cliff-top retreat which is quite independent of cliff-toe erosion.
The events at sites in Lyme Regis and Charmouth are summarized to illustrate the hazard presented by Head deposits in cliff-top areas.
Factors affecting the transition between the various types of mass movement in coastal cliffs consisting largely of overconsolidated clay with special reference to Southern England
Authors: Bromhead E. N. 
Published: November 2007

Summary
At present, the most widely accepted hypothesis for the transition from mudsliding to deep-seated rotational slipping as the dominant agent of mass transport in actively eroding clay cliffs is that the transition depends on the rate of marine erosion at the toe of the slope. This paper explores an alternative theory, that the transition from one type of behaviour to another depends largely on the nature of the materials at the crest of the slope and to a lesser, but still important, extent on the groundwater hydrology.
The main argument behind this alternative theory is that the presence of stronger soil strata at the crest of the slope inhibits the mudslide behaviour that would otherwise occur and hence form a toe-protecting ‘mudslide barrier’. This allows marine action to erode the toe of the slope directly, causing it to be oversteepened, and ultimately precipitates a deep-seated rotational landslide. Where the coastal cliffs are capped with thick, hard and jointed caprock the slides tend to be of the multiple rotational kind.
The application of wave refraction diagrams to shoreline protection problems: with particular reference to Poole and Christchurch Bays
Authors: Henderson G. , Webber N. B. 
Published: November 2007

Summary
Wave refraction has an important role in the evolution and day-to-day behaviour of shorelines and beaches. It is often the major factor in dictating the magnitude and direction of the littoral drift.

The development of a wave refraction model for a particular site, (Poole/Christchurch Bays in the central south coast of England), is described. The computational technique is very powerful and an area of 2500 km
2
of sea bed has been reproduced with the refraction behaviour superimposed for various wave directions and periods in deep water. In assessing the results, regard must be paid to the simplifying assumptions and the effects of offshore shoals.
Additional observations on the Folkestone Warren landslides
Authors: Hutchinson J. N. , Bromhead E. N. , Lupini J. F. 
Published: November 2007

Summary
The Folkestone Warren landslides are first compared to the landslides at geologically related sites on the northern coast of France and the southern coast of England. Additional historical data is then presented on the Warren landslides, particularly that of 1915, and the influence on these of the interruption of littoral drift produced by the Folkestone Harbour works is examined. An indication is also given of other considerable mass shiftings which have taken place in the Warren since the early nineteenth century. A preliminary morphological study is made, the features being linked, where possible, with the historical data. The degree to which the frequent Chalk falls from the High Cliff are controlled by the joint pattern is briefly examined and the recent subsurface investigations in the Horse's Head area are reviewed and discussed.
The existing back-analyses of the slips are critically re-examined in the light of the fresh historical and morphological data and additional back-analyses are carried out. Measurements of the residual strengths of the high and low liquid limit Gault are made, in two different ring shear machines, and compared with the combined results of the back-analyses.
Permeability of three compacted tropical soils
Authors: Ola S. A. 
Published: November 2007

Summary
This paper presents studies of permeabilities of three soil samples of widely differing properties at various degrees of saturation, various compactive efforts and various thixotropic strength ratios. The soils studied consist of a soft clay shale–attapulgite, a black cotton soil, and a lateritic kaolinitic soil. The results indicate the attapulgite to be the most structure sensitive and the lateritic soil the least structure sensitive. The permeabilities reflect these structural behaviours of the soils. Based on the test results, a practical back pressure is recommended for complete saturation of these compacted soils. The influence of moulding moisture contents on permeabilities are presented and values of thixotropic strength ratios for the three soils are also recommended.
Coastal engineering problems at Clacton-on-Sea, Essex
Authors: Harris W. B. , Ralph K. J. 
Published: November 2007

Summary
Erosion along the frontage at Clacton has necessitated the progressive protection of the cliff and foreshore during the last 100 years. The cliffs consist of Pleistocene gravels overlying London Clay and reach a level of 20 m above Ordnance Datum (Newlyn). The top of the clay is irregular and incised by buried channels which allow water to drain to the front of the cliff and weaken the clay forming the cliff base. On the foreshore the stability of the existing sea walls protecting the cliff base was endangered by erosion on the downdrift side of the two large groynes constructed a few years previously.
Remedial measures included the relief of perched water tables and drainage of the cliff by vertical and inclined bored drains; the protection of the toe by constructing stepped aprons and sea walls of pre-cast concrete components; the installation of a new groyne system and replenishment of foreshore material.
Contamination of a Chalk aquifer by mine drainage at Tilmanstone, East Kent, U.K.
Authors: Headworth H. G. , Puri S. , Rampling B. H. 
Published: November 2007

Summary

Arising from the discharge at the surface of minewater drainage pumped from a mine in the Kent Coalfield, which underlies the Chalk of East Kent, U.K., an area of some 27 km
2
of the Chalk aquifer has become contaminated with saline water having concentrations of chloride between 200 and 5000 mg/l. Between 1907, when the first shaft was sunk, until 1974, when the discharge onto the Chalk ceased, it is estimated that 318 000 tonnes of chloride were discharged, and only about 15% has so far been dissipated by stream flows. An investigation has been carried out to determine the size and shape of the plume of contamination, and to examine possibilities for rehabilitation of the aquifer. The work has shown that the top 40-50 m of Chalk has become saturated with highly saline water, but at greater depths the contaminant is localized around well-developed fissures. The results of fifteen months pumping of a production borehole located near the centre of the pollution plume suggests that a long period would be required for the contamination to be cleared, and this has been supported by the results of a mathematical model.
Rebound, its nature and effect on engineering works
Authors: Nichols T. C. 
Published: November 2007

Summary
Rebound of rock masses, defined as the expansive recovery of surficial crustal material, either instantaneously, time-dependently, or both, initiated by the removal or relaxation of superincumbent loads, is found in most geological terrains. The applied loads resulting from past or present geological processes are removed or relaxed by (1) natural processes such as valley erosion (long term) or (2) artificial processes such as excavations (short term). Rebound features are most pronounced if the time period of load removal is short compared to the relaxation time of the material, assuming that relaxation time is a material property.

Some factors that affect rebound and its intensity are:

Initial fabric, lithology, crack density, anisotropy, density and moisture content.

Magnitudes of deviatoric stresses (stress differences, stress ratios) operating at the time of load removal, their orientation with respect to the free surface and their rate of unloading.

Initial strength and time-dependent strength.

Environmental conditions, such as moisture, temperature and other weathering agents.

The near-surface stress distribution and time-dependent strain release measured within different geological terrains suggest that the redistribution and/or release of stored-strain energy within rock masses may be a major factor contributing to rebound. Strains, stored in the rocks as a result of past and present geological loads, can be released by excavation processes. As new surfaces are formed, the rock mass changes volume, creating physical property changes that include increased void space and higher permeabilities, thus allowing more rapid access for chemical agents that accelerate the weathering process. Rebound is a rate-dependent process that is manifested differently in various geological terrains.
Long-term stability is dependent on changing fracture density and the rate at which strength decreases within near-surface rock material. The strength reduction may be, among other things, a function of the internal decay of cohesion due to the development or propagation of fractures. The time-dependent processes of rebound and the ambient stress fields are important in the development of criteria for the long-term design of engineering installations that are placed within or on disturbed rock masses.
Fault control of groundwater flow and hydrochemistry in the aquifer system of the Castlecomer Plateau, Ireland
Authors: Daly D. , Lloyd J. W. , Misstear B. D. R. , Daly E. D 
Published: November 2007

Summary
The Westphalian strata of the Castlecomer Plateau contain two main sandstone aquifers that are in variable hydraulic continuity due to major fault displacements. The faulting separates the plateau into three effectively independent groundwater blocks. A hydrochemical study shows that carbonate dissolution and ion exchange are the two dominant chemical processes active in the aquifer and that the degree to which they occur is a function of the ability of the aquifer to transmit water which is controlled by fault displacement.
Cement hydrate development at opal-cement interfaces and alkali-silica reactivity
Authors: Baker A. F. , Poole A. B. 
Published: November 2007

Summary
Electron probe microanalysis data indicates that sodium, potassium, and calcium ions migrate into opal aggregate from the cement paste in experimental alkali-silica reactive concretes. The reaction also modifies the development of cement phases at the interface with the opal and these modifications are reflected in modifications of the tensile strength of the opal/cement bond. It is suggested that the calcium silicate hydrates which develop in the cement at the interface with opal may control the migration of alkali ions into the opal. With high alkali concentration in the cement pore fluids this hydrate layer at the interface may not develop completely allowing high concentrations of alkali ions to reach the reacting opal causing a change in the composition and properties of the alkali-silica gel reaction product.
Properties of aggregates affecting concrete in North America
Authors: Gillott J. E. 
Published: November 2007

Summary
Aggregates compose the largest single component in concrete and significantly affect its strength, durability and appearance. The mechanical properties of concrete are affected by the strength of the cement-aggregate bond and by other factors such as texture and soundness of the rock. External agencies attack concrete and reduce its durability by both physical and chemical processes. Physical mechanisms include cyclical freezing and thawing, wetting and drying. Chemical deterioration results from reaction with sulphate-bearing waters, acids, a marine environment, industrial effluents and similar corrosives. Internal compatibility is essential, as deleterious interaction between concrete constituents may cause poor durability, as in the case of expansive alkali-aggregate reactions. Deliberate exposure of aggregates, sometimes used architecturally, may give concrete a pleasing appearance, but localized stains from weathering of aggregate particles lead to an unsightly appearance. Relatively few attempts have been made to improve aggregate properties artificially and ‘unsound’ aggregate is simply rejected. Depletion of good quality supplies near major centres of construction suggests that more pre-treatment of marginal aggregates may become economically attractive in the future.