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in engineering geology abrasion is significant in three main ways erosion of the earth s surface damage caused by abrasive minerals and rocks to machinery selection of minerals that are suitable for use as industrial and domestic abrasives this is a complicated topic that is not yet fully resolved matters of sp... |
ry hard minerals a variety of abrasiveness tests have been developed for different purposes currently there is no universally accepted test for soil abrasiveness but much research is in progress mirmehrabi et al 2016 there is also an issue of the scale of tests these can be at a real scale in the tunnel excav... |
susceptibility to abrasion and therefore of the performance of the aggregate when subjected to abrasion during use abrasion is important in wind water and glacial erosion but it is also significant for determining the suitability of minerals for use as industrial and domestic abrasives blunting and wear on machi... |
neering terms the high acidity poses heightened risks of corrosion of steel and other materials thus demanding careful galvanic protection the high sulfate concentrations pose a risk of rapid weathering of concretes based on ordinary portland cement sulfate resistant cements must be specified for structures likely ... |
tres to kilometres blowouts in size particles are transported in three different ways upwelling currents of air support small suspended particles less than 2 mm in diameter and can hold them in suspension indefinitely as haze or dust depending on how much is entrained sand sized particles can bounce some 1 cm... |
oss and deterioration dust emissions can be reduced by keeping exposed surfaces moist or stabilizing them and enclosing plant and equipment aeolian processes can be relevant to engineering geology and engineering geologists in several ways the difficult site investigation and sampling conditions where dry poorly ... |
te topographic maps using a stereoplotter a mapper would float a red dot along the surface of the ground as viewed through two air photographs the red dot could then be moved along x and y axes following the ground contour while remaining at the same elevation tracing this dot led to the creation of contour line... |
z s theories contradict uniformitarianism but others argued that no sufficient source of water was available in 1956 bretz published results from a second field trip this time including air photographs showing massive ripple beds tens of meters high that began to turn the tide of criticism that had marred his work ... |
programs the geophysicist builds a geologic interpretation from the digital aeromagnetic data incorporating geological mapping and other geophysical information gravity seismic reflection where available fig 2 interpretations often involve both map based information e g a fault map and three dimensional in... |
ed at a local scale when natural aggregate is unavailable and is largely dependent on the bedrock lithology of the region most crushed aggregate is produced for concrete and road construction purposes most igneous rocks like dolerite and sedimentary rocks such as limestone and dolomite are excellent sources for cru... |
umber of tests are available to determine the reliability of adhesion of a bitumen binder to aggregate when water is present adhesion and binder stripping problems tend to arise when the bitumen mixture is permeable to water or the aggregate is exposed to wet and cold crushing test provides an indication of aggreg... |
ine solution reacts with amorphous silica to produce a viscous alkali silicate gel as the reaction proceeds ca2 ions are dissolved into the pore water these react with the gel to form solid calcium silicate hydrate whereas the alkaline solution converts the remaining siliceous minerals into bulky alkali silicate gel... |
e fluids responsible for inducing alteration of minerals may eventually deposit ore minerals as a result of thermal and chemical changes therefore mapping alteration halos is key to discovering hydrothermal mineral deposits that may or may not outcrop on the surface alteration is common with porphyry skarn and oro... |
stress samples of alluvial silty medium to coarse sand subjected to direct shear testing might have a linear regression peak shear strength represented by eq 1 eq 1 describes an angle of internal friction of 33 5 and a cohesion intercept of 37 15 kpa a silty medium to coarse sand with nonplastic silt would b... |
motion until the slope reaches its upper angle then an increase in the slope angle triggers an avalanche transporting grains down the slope at the end of the avalanche a new slope forms at a lower angle if the rotating speed is increased both upper and lower angles disappear and the slope angle approaches a cons... |
cture network of consolidated sedimentary sandstone limestone igneous and metamorphic rocks some materials such as clay can have a high porosity but the scarce interconnection between pores makes such clay rich rocks quite impermeable thus creating a confining layer regarding the confining layer those layer... |
eshwater topping the seawater can be computed by the ghyben herzberg equation an aquitard is a leaky confining bed that transmits water at a very slow rate to or from an adjacent aquifer due to the reduced hydraulic conductivity aquitards permit water to move through at very slow rate as compared to the adjacent aqui... |
in river channels where it may be called riprap may be exposed to forces of turbulent clear water flow with little suspended sediment other applications may be in a coastal environment and exposed to high energy waves on beaches composed of gravel and cobbles the high energy beach environment exposes armour stone... |
global great acceleration of the mid twentieth century the rate of accumulation the extent of reach of such landscape modification and diversity of composition of the deposits have increased dramatically this contribution considers how this anthropogenic landscape is described and classified by geologists how suc... |
round where it is impractical to delineate areas of worked ground and made ground within it housing estates or golf courses disturbed ground mineral workings where excavations and associated subsidence are complexly associated with each other collapsed bell pits shallow mine workings etc transportation route... |
for example in the uk lack sufficient waste materials to allow reinstatement and high water tables make them unsuitable as landfill locations so commonly remain as flooded workings following completion although there can be opportunities for restoration of margins to support some wildlife subsidence of up to 50... |
ult from land reclamation from lakes and seas the generation of extensive agricultural land e g polderization in the netherlands typically creates little artificial deposits in contrast reclamation increases living space facilitates construction of industrial sites or to locate major airports e g the palm ju... |
on and vertical scale of geomorphological features which can be attributed to specific land uses such as railway embankment or quarry excavation ground investigation techniques made ground is heterogeneous and can rapidly vary in composition both laterally and vertically in order to determine the nature of fill ma... |
ater composition electromagnetic em data can show high electrical conductivity in the near subsurface relating to contaminant plumes associated with leakage from landfill sites waste dumps mine waste tips and industrial pollution it can also provide information on foundations archaeological structures and pres... |
t is one of the most important index properties of fine grained soils barton bandis criterion a series of rock joint behavior routines which briefly stated allow the shear strength and normal stiffness of rock joints to be estimated graphed and numerically modelled for instance in the computer code udec bb cou... |
read footings in certain geologic settings for example holocene marine clay deposits or for very heavy foundation structural loads tall buildings or for facilities that generate strong ground vibrations reciprocating compressors shallow spread footings would have insufficient capacity or would result in intol... |
ilure results from a geotechnical condition of a relatively strong surface soil layer that forms a crust over a weak soil layer the structural load essentially pushes the footing and strong soil into the underlying weak soil layer causing consolidation or compaction of the weak soil without noticeable bulging at the ... |
sually underconsolidated with high or very high compressibility mineralogical components of rocks are altered and modified when exposed to earth surface conditions in response to different atmospheric agents and insolation that may result in the disaggregation physical weathering or the decomposition chemical weat... |
mployed since it is more rapid and cost effective than mechanical means of excavation or demolition the primary blasting impacts of air blast noise fly rock thrown projectiles underwater overpressure pressure wave passage through water and ground vibration are dependent upon the shot pattern parameters ambi... |
with its energy transmitted by means of rods to a solid tool or hollow tube sampler placed at the bottom of the borehole this system which has advantages in unconsolidated soils silt sand and gravel usually takes longer and is more expensive than rotary drilling the rotary technique fig 1 is the most frequ... |
y designation rqd of all the core samples obtained is determined deere and deere 1988 this index expressed as a percentage is defined as a quotient between the sum of the length of the core pieces and the total length of the core run there are different tools for the collection of samples and depending on the... |
common to keep a record of the water table level in every borehole fig 2 not only during the drilling but also once it has been completed at least until the end of the field work the main tests undertaken in situ in a borehole are as follows standard penetration test spt the spt is the most common test among... |
is necessary to resort to pumping or laboratory tests the most frequent ones are referred to as the lefranc and lugeon tests monnet 2015 the lefranc test is carried out within a borehole during the drilling or once it has been completed this test estimates the permeability coefficient k in granular soils grav... |
different types of tools are available to obtain disturbed and undisturbed samples undisturbed samples are those that best maintain the physical structure and properties of the soil and lead to more reliable laboratory test results tests undertaken in situ in a borehole include penetration tests pressuremeter and ... |
rmations water will eventually flow into the hole drillers or hydrogeologists on site will carefully monitor the depth of water strikes and keep a note of the formations in which they occur sonic drillingtechnique an oscillator in the drill head generates high frequency resonant energy which is directed down ... |
ine the slip planes of landslides boreholes are also sunk for dewatering of excavations and draining water from landslides in boreholes for water supply the bottom section of the lining has slots to allow water to enter the borehole gravel is placed at the bottom of the lining to improve flow and provide filtration ... |
equires less capital outlay than many other mining methods and it makes it possible to work in otherwise inaccessible areas that are too dangerous for conventional mining it has a relatively low environmental footprint and allows for better mobility when it comes to changing mining locations more selectivity can be a... |
dividual sites may cover many hectares or be small and scattered some can be easily redeveloped but many have problems of contamination pollution instability and obstructions from past uses that add to difficulties and costs of either redevelopment or rehabilitation surficial deposits on such sites are often of ant... |
rther contaminated by materials such as asbestos in which case they must be landfilled as hazardous waste simplistically it might be thought that brownfield sites are environmentally undesirable and should be fully remediated to benefit the environment wildlife and people that is often true but there are importan... |
fset costs of remediation uk there have been two main philosophies for remediation to make the site safe for all possible subsequent uses some specific uses following remedial action the former is usually much more expensive so the latter is more often adopted building stone is a generic term referring to a... |
lies incompetent beds e g clay mudstone siltstone and sand following valley incision the incompetent material is extruded from beneath the caprock initially as a result of stress relief and a reduction in shear strength due to pore pressure increases associated with thawing during periglaciation the overlyi... |
ing salt formation and any impurities in it producing the anhydrite and gypsum interaction of anhydrite and gypsum with bacterial activity can produce sulfur in the cap rock of salt domes sometimes in deposits of economic value for mining capillarity in soils refers to the upward flow of water above the groundwater... |
inal size from 18 to 30 in 457 to 762 mm a casing of smaller diameter 13 in or 339 mm called a surface casing is placed inside the conductor casing and cemented in place to isolate freshwater aquifers that may be present near the surface an intermediate casing may be required for a deep well in which a well ... |
covery process could be excessive and detrimental to surface and subsurface facilities morgenstern et al 1988 casing failures have been reported in thermal recovery processes talebi et al 1998 mechanical energy released from hydraulically induced fractures or casing impairment and failure can generate microseis... |
ial loads are statically applied to the test pile in increments and the settlement of the pile is recorded the axial loads can be applied by stacking concrete blocks on a loading frame attached to the pile or by exerting reaction forces using hydraulic jacks with a reaction frame the axial load settlement record pr... |
soil refers to the geometric arrangement of soil or mineral particles and depends on genetic chemical mineralogical characteristic as well as past stress conditions of the soil interparticle force also influences the soil structure for cohesive soils interparticle force is much higher than in noncohesive soils ... |
electric power generation diversion dams are constructed to provide head for water conveyance systems canals ditches tunnels detention dams retard flood runoff to reduce the effect of sudden floods the process in which wet soils dry and soil moisture content decreases as the moisture evaporates into the surro... |
oundwater is encountered during excavation problems can occur either by flooding of the excavation or in the form of instability induced by its presence depending on the nature of the ground being excavated the groundwater conditions encountered can vary greatly from site to site a thorough hydrogeological investig... |
lower in less soluble rocks limestone chalk and dolomite but quicker in more soluble gypsum over time the fractures become enlarged and increasingly interlinked eventually forming complex subsurface drainage systems and in the stronger rocks cavernous ground the dissolution features form a landscape known as k... |
and thus obtaining an adequate database of information the location depth and number of drill holes are important controlling parameters of the project budget these parameters change depending on the importance and type of project geological conditions and information provided from preliminary studies below th... |
ank and slope stability ice debris frozen into the beds and lateral margins of glaciers and ice sheets erode and smooth adjacent rock surfaces these processes erode smooth and polish rock surfaces but also round and polish the debris that impact on those rocks plant machinery and other equipment are abraded d... |
quires examination of mechanical properties of rock and soil masses mineral based texts also neglect the sizes and shapes of grains the cerchar abrasive test was developed to assess the potential abrasion damage to plant and equipment for instance cutter life in the field and is also significant for building and ... |
riably rich in sulfate the total acidity in mine drainage has two components proton acidity due to the presence of high concentrations of hydrogen ions h that manifest in a low ph below 6 would typically be regarded as acidic in this context and metal acidity due to the presence of the metals listed above ... |
oh the solution is alkaline ph 7 the ph value is an important characteristic of all aqueous solutions and natural water bodies rivers lakes seas oceans the ph value along with the reduction oxidation redox potential determines the possible concentration in aqueous solutions of different chemical elem... |
direction at distances wavelengths reflecting the average length of particle bounces the resulting ripples have the coarser material at the crests and finer material in the troughs larger scale movements build dunes by saltation and creep grains move up a slope towards a crest accumulate there and when the criti... |
largely overtaken by color images near infrared aerial photography is taken where the film or sensor is sensitive to the near infrared spectrum 700 900 nm it is frequently used to identify vegetative health and to reduce the effects of haze infrared photography is often called false color photography the ability ... |
nd and changes in land use were accurately captured by repeated air photograph surveys much of the country is covered at intervals of 10 years or less beginning in the mid 1950s similarly changes in coastlines the widespread existence of permafrost the ongoing movements of rivers and the development of transporta... |
e magnetic minerals contain various combinations of induced and remanent magnetization at exploration depths the earth s primary magnetic field is perturbed by the presence of magnetic iron oxide magnetite the most strongly magnetic and the most common magnetic mineral iron titanium oxides titanomagnetite titan... |
he spatial geometry of bodies of rock and the presence of faults and folds because different rock types differ in their content of magnetic minerals even if the bedrock is obscured by surficial materials such as sand soil or water aggregate is granular material such as sand gravel or crushed stone used for a vari... |
ir composition characteristics properties and suitability for specific uses natural and crushed stone aggregate serves a wide list of needs and uses around the world most aggregate is for construction purposes and of this most is used in portland cement concrete and bituminous mixes specific uses require specific... |
he materials specific gravity water absorption tests involve two measures of specific gravity apparent specific gravity and bulk specific gravity the former determines sg of aggregate minus voids and the latter sg of aggregate sample including the voids the water absorption test is simply the difference between ... |
t a reference curve to establish whether these fall within one of three ranges innocuous deleterious or potentially deleterious the test identifies highly reactive aggregates fairly well but not slowly reactive aggregates and is helpful rather than reliable bar methods mortar bars are immersed in naoh solutio... |
hlorite carbonate pyrite indices the angle of internal friction is a physical property of earth materials or the slope of a linear representation of the shear strength of earth materials earth materials that are unconsolidated and uncemented typically are called soil by engineers and geologists and may be called sed... |
measured using different methodstwo different slopes can be differentiated during the pile formation as grains are gradually added to a heap they can pile up to an upper angle of repose once masses slump a new surface will form at a lower angle of repose as a result the angle of repose varies repeatedly during t... |
le of initial yield and the lower angle as the residual angle after shearing carrigy 1970 noted that there is no agreement reached as to what angle should be measured francis 1986 indicated that some confusion exists in the precise meaning of the term angle of repose and a single angle of repose is inadequate ... |
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