Injection processes grouting

It is sometimes possible to change the properties of the ground encountered by injecting materials of various sorts into the voids of the soil. These changes include (1) reduction in permeability (2) increase in strength and (3) decrease in compressibility, or a combination of these. A major use is for filling voids in mine workings and karstic limestone. Cases in which the reduction in permeability is important include (1) the formation of grouted cutoffs under dams (2) grouting fissured rocks...

Soil classification chemical

Organic content is expressed as the percentage by mass of organic matter present in the soil. The organic matter in a sample of soil dried in an oven between 105 and 110 C is oxidized in a 500ml conical flask by the addition of 10 ml potassium dichromate solution and 20 ml concentrated sulphuric acid. The sample of soil should weigh between 0.2 g for peaty soil and up to 5 g for a soil with low organic content. Processes of titration determine the volume of potassium dichromate used to oxidize...

Soil compaction

A9.1.3.1 Dry density moisture content relationships Laboratory compaction tests determine the mass of dry soil per cubic metre obtained when the soil is compacted in a specified manner at a specific moisture content. Repetition of the test over a range of moisture contents provides a compaction curve indicating the optimum moisture content and maximum dry density obtainable for the compactive effort applied. The original 'Proctor' test simulated the compactive effort of construction plant in...

Strength tests

A9.1.4.1 Californian bearing ratio (CBR) The Californian bearing ratio (CBR) test was developed in 1938 to evaluate Californian highway subgrade strengths and became the basis for the design of road and airfield pavements throughout the world. It is used both in situ and on prepared samples in the laboratory, but is limited to materials of particle sizes up to a maximum of 20 mm. The test determines the relationship between force and penetration when a cylindrical plunger 1935 mm2 in...

A v

Figure 5.1 Layer of fluid illustrating laminar flow as the coefficient of viscosity. If force is defined by force mass x acceleration then i will have the units off (dv dy), or ( A x L x r- x -* ) ( x T ' x L ' ) i.e. p-'r1 , where M represents mass, L length, and 7 time. Thus if newtons (i.e. kilogram metres per squared second) are adopted for the force of resistance, metres for length, metres squared for area, and metres per second for velocity, then the coefficient of viscosity takes the...

Acknowledgements

This chapter has been revised to incorporate the many advances in rock mechanics and rock engineering that have taken place since the 3rd edition of this book was published in 1975, but the author acknowledges that some parts of the chapter were based on the 3rd edition text prepared by Dr J. A. Franklin, then of Rock Mechanics Ltd and now Professor of Earth Sciences at the University of Waterloo, Ontario, and President of the International Society for Rock Mechanics. The author is grateful for...

Anchored bulkheads

An anchored bulkhead is usually in the form of a steel sheet-pile wall supported by ties at one level only and by passive pressure against the toe. However, anchored bulkheads may also be constructed with timber, precast reinforced concrete sheet piles, or continuous-bored piles. Calculations of active and passive earth pressures follow the same lines as for retaining walls but analysis of the stability of an anchored bulkhead requires the determination of bending moments in the piling and of...

Appendix Ground improvement

There are numerous cases in which the properties of naturally occurring soil or fill material can be improved or changed to help solve engineering problems arising either in temporary or permanent works. The methods of ground improvement cover a wide range of techniques - often referred to as geotechnical processes - and include compaction, moisture control, stabiliza tion, grouting and reinforcement. Reference should also be made to the use of geotextiles for reinforcement, separation and...

Appendix Laboratory testing of soils

This appendix gives a brief outline of some of the main laboratory tests required to classify individual soils and to indicate their compaction and strength characteristics. In order to obtain reliable results, it is essential to follow the recommendations in Chapter 11 with regard to sampling and then to follow closely the practices recommended in the appropriate standards for sample preparation, testing and reporting. The outline in this section is based on British Standard BS 1377 1975 but...

Appendix Pile capacities

Piles are used to transfer foundation loads to a deeper stratum when the surface soils are too weak or too compressible to carry the load without excessive settlement. Details of pile types and their design and use are given in Chapter 17. The reader's attention is drawn to the references in Chapter 17 for further information, particularly to BS 8004, Tomlinson61-62 and to series of CIRIA PSA piling guides. In this appendix, methods are given for estimating the carrying capacity of piles in...

As

Gives a parabolic interaction curve in the nonelastic range which is tangential to the squash line at A 0, and to the buckling hyperbola at the point < rcr i< TY. The secant formula. The secant formula is derived assuming that the axial forces on the column have an initial eccentricity e (Figure 2.52(a)). In this case it can be shown that c is the distance from the neutral axis to the extreme fibre of the section. The Perry-Robertson formula. Assuming that the column has an initial...

Av

Figure 7.3 Scale changes on a tilted and vertical aerial photograph scale, although an average nominal value for the scale can be calculated (often referred to as the contact scale). Stereoscopic viewing and the measurement of the perceived stereomodel is fundamental to photogrammetry and thus of great importance. If two photographs taken from different viewpoints of the same area are viewed simultaneously, the difference in position of a common image point on the two photographs results in a...

B H E Settlement Bolt

Figure 6.44 Building Research Establishment settlement bolt system adjustment using the method of variation of coordinates (see section 6.3.1.4). This not only enables the most probable values of the positions to be arrived at, but also statistical data about the precision and reliability of the network to be determined. Furthermore, by interpreting these statistical indices and then the results of a network adjustment from two different epochs it is possible to evaluate the statistical...

Ljx

Mineral composition depends largely upon the chemical composition. The chief minerals present will normally be silicates of the six common metal cations noted, together with quartz, when silica is present in excess. The minerals which actually form will be controlled by the silica percentage and the relative abundance of the cations. For example, silica-poor silicates such as olivine D Figure 8.5 Idealized types of sedimentary bedding. (After Sherbon Hills (1972) Elements of structural geology,...

B r

Elements intersecting at a single point the additional torque component becomes where ,, is the total moment of inertia of the cross-section about the y axis. Combining this with the torque required for the uniform torsion of the bar, we obtain Equation (2.174) can be expressed in the more general form where r is a constant called the warping factor. Its values for various cross-sectional shapes are given in Table 2.5. The differential Equation (2.175) can be solved for various values of T...

Wep

The method is very popular for several reasons. Firstly, it is a more flexible method than triangulation. In the case of triangulation, the positions of the control stations must be chosen so that not only are they intervisible, but also that the triangles formed are well conditioned. For this reason the reconnaissance stage in triangulation projects is extremely important and often very time-consuming. In contrast, with traversing, much less attention has to be paid to the reconnaissance...

Basic geology

Rock is strictly defined in geology as any natural solid portion of the Earth's crust which has recognizable appearance and composition. Some rocks are not necessarily hard, and in discussion a geologist may call peat or clay a rock as he would granite or limestone. There are three major classes of rocks (1) Sedimentary rocks formed by the deposition of material at the Earth's crust, e.g. sandstone, clay. (2) Igneous rocks formed from molten rock magma solidifying either at the Earth's surface...

Bearing capacity of shallow foundations

There are two groups of methods of determining ultimate bearing capacity (1) analytical methods and (2) graphical methods. The graphical methods are very flexible and will cover any conditions likely to be found in practice, but they are rather cumbersome in use. The analytical techniques, which are only strictly applicable in cases in which the soil is uniform, are quicker and easier to use, and therefore are the most often used. The most general formula for the ultimate bearing capacity of a...

Bibliography

B. (ed.) (1980) Developments in close-range photogrammetry, Elsevier Applied Science, London, 222pp. Burnside, C. D. (1979) Mapping from aerial photographs. Granada, London, 304pp. Colwell, R. W. (ed.) (1983) Manual of remote sensing, vols I and II, 2440pp. European Space Agency (1984) Remote sensing applications in civil engineering. ESA, Publication No. SP-216, 198pp. Karara, H. M. (ed.) (1979) Handbook of nontopographic photogrammetry. American Society of Photogrammetry, 206pp....

Bs

Recommendation for method of measuring workability Mass concrete foundations without vibration. Simple reinforced sections with vibration Normal reinforced work without vibration, and heavily reinforced sections with vibration Sections with congested reinforcements. Not normally suitable for vibration As for high workability plus large volume pours British Standard requirements for aggregate gradings. The criterion for determining what proportions of sand and coarse aggregate should be used is...

Characterizing rock mass properties

Rocks may be classified using geological names only, but this approach can mislead because the names are sometimes general and depend on properties that are of little engineering significance. For example, 'granite' can be a crumbly sand or a broken rubble rather than the monolithic material implied by the name. Shales, mudstone and limestone can also exhibit an extremely broad range of engineering properties. On the other hand, there are over 2000 igneous rock names in existence, reflecting...

Computers

Computers and computing have made a substantial impact on most walks of life, civil engineering not excepted. The pace of development in computing is substantially greater than for any other area of activity in the engineering world. Although other subject areas are subject to bursts of activity from time to time, when research or some specific project provides the necessary spur, computers are developing rapidly all the time, whether the engineering world wishes it or not. In consequence a...

Computers in surveying

Computers have, throughout their development, been extremely important in the fields of surveying and mapping. Initially, their use was almost exclusively restricted to the 'number crunching' requirements of large organizations carrying out geodetic computations or the adjustment of major control frameworks. Operations of this type were carried out on large mainframe computers in batch mode. Whilst slow and cumbersome to operate by modern computing standards, these early computers offered...

Consolidation

The ultimate change in volume of a soil occurring under a change in applied stress depends on the compressibility of the skeleton of soil particles. However, the water in the voids of a saturated soil is relatively incompressible and, if no drainage takes place, change in applied stress results in a corresponding change in pore pressure, and the volume change is negligible. As drainage takes place by flow of water from zones of high excess pore pressure to zones of less or zero excess pore...

Construction methods and monitoring

Processes of rock fragmentation are known collectively as comminution processes. In spite of a considerable amount of research aimed at improving these techniques the gap between theory and practice is still great and an empirical approach is more often used. Much research has been directed towards understanding the mechanisms of fragmentation during drilling, in order to improve the design of conventional mechanical bits (diamond bits, percussion or rotary drag bits) and to develop new ways of...

Construction of flow nets

Four methods of constructing flow nets are in general use. (1) Mathematical. For simple boundary conditions, the governing differential equation (Laplace) can be solved mathematically. Many computer-finite element packages now contain seepage programs which can be used to solve the more complex steady-state seepage problems, e.g. with layered soils and complex boundary conditions. (2) Electrical analogy. The differential equation for flow nets is the same as that for flow of electricity, and...

Contents

9.1 The basics of soil behaviour 9 3 9.1.1 Effective stress 9 3 9.2 Design and limit states in soil mechanics and 9.3.1 Bearing capacity of shallow foundations 9 7 9.3.2 Bearing capacity of deep foundations 9 9 9.3.4 Settlement of granular soils 9 15 9.3.5 Depth corrections 9 16 9.4.1 Active and passive conditions 9 17 9.4.2 Active pressure 9 18 9.4.3 Passive resistance 9 20 9.4.4 Distribution of pressure 9 20 9.4.5 Strutted excavations 9 20 9.4.6 Anchored bulkheads 9 21 9.4.7 Overall stability...

Contributors

Peter Ackers, MSc(Eng), CEng, FICE, MIWEM, MASCE Hydraulics consultant The late J Allen, DSc, LLD, FICE, FRSE Emeritus Professor, University of Aberdeen Manager, Underwater Engineering Group, London SCC Bate, CBE, BSc(Eng), PhD, CEng, FICE, FIStructE Formerly at the Building Research Establishment, and later consultant to Harry Stanger Ltd Keith M Brook, BSc, CEng, FICE, FIHT Wimpey Laboratories Ltd Staff of Central Electricity Generating Board Generation Development and Construction Division...

Data acquisition

Data can be acquired for remote sensing from a variety of aerial platforms, although fixed-wing aircraft and unmanned orbiting satellites are the most common. Both have specific and complementary advantages. Aircraft, for example, enable small localized phenomena to be investigated at high levels of resolution, whereas satellites enable wide synoptic views of the terrain to be obtained, often on a repeatable basis, but at much lower resolution. Vertical panchromatic aerial photography taken...

Definitions of terms used in soil mechanics

All soils consist of solid particles assembled in a relatively open packing. The voids may be filled completely with water (fully saturated soils) or partly with water and partly with air (partially saturated soils). The relationships between void space and the volume occupied by the particles are fundamental and are characterized by the following definitions. Porosity n volume of voids Fv total volume of soil Vv Voids ratio e Kv volume of soil particles Vt. (9.86) Hence e n (l-n) and n e ( 1 +...

Depth corrections

Where foundations are below ground level, and where elastic theory based upon a load applied at ground surface has been used to obtain foundation stress increases for settlement analysis, a correction factor is generally made to allow for the effect of the soil above foundation level. Traditionally the values of Fox27 have been used these lead to a maximum possible reduction in settlement (for deep foundations) of 50 . Because the figures are based upon elastic analysis they tend to...

Design and limit states in soil mechanics and foundation engineering

Unlike virtually all other materials dealt with by civil engineers during the course of their work, soil is naturally occurring. It is inherently variable, not only from site to site but also at different levels and plan locations at any one site. The extent of its variability can be judged by examining the typical limits of some of its most important properties Undrained shear strength c 5-300 kN m2 Coefficient of permeability k 10 2-l0 'm s Coefficient of compressibility my 0.01-3.00 m2 MN If...

Design methods

The purpose of designing a rock structure (e.g. a tunnel, cavern, open cut or foundation) is to decide the size and shape of the excavation, to determine whether measures to improve the rock conditions such as grouting, rock reinforcement, anchoring or drainage are needed, whether rock support such as shotcrete, mesh, rockbolts, steel arches, or concrete liners are required and to select and design the appropriate systems as necessary.

Digital image processing DIP

Digital image processing is a crucial stage in the effective use of Figure 7.29 SPOT nadir and off-nadir viewing. (Courtesy. SPOT Image) Plane mirror steerable by ground control Off-nadir Nadir Off-nadir viewing viewing viewing Off-nadir Nadir Off-nadir viewing viewing viewing Figure 7.29 SPOT nadir and off-nadir viewing. (Courtesy. SPOT Image) Figure 7.30 SPOT panchromatic image of part of Montreal (SPOT data copyright CNES, 1986, image provided by Nigel Press and Associates) Figure 7.30 SPOT...

Dsvp deydPf y j g y de

From Figure 1.32, < J r dx j 2 fix) dx 1.5.5.2 Polar coordinates From Figure 1.33, dA p2dd Therefore A p2d9 J (0) 2< (Note. For curve cutting x axis, equate fix) to zero, find values of x for v 0 and integrate between these values for the area cut off by the x axis.) When the area lies above and below the x axis integrate the positive and negative areas separately and add algebraically. Where the area does not extend to the x axis in the case of cartesian coordinates, or to the origin in...

Earth pressure

The pressure on a wall or structure in contact with soil is a complex matter, depending upon (1) how the wall moves (2) how the soil-wall system is placed (3) the strength parameters of the soil and (4) groundwater conditions. Classical earth pressure analysis, which dates back to the eighteenth century, considers only the restricted cases of rigid walls which rotate about their base, either into or away from the soil. It is implicitly assumed that the soil is placed before the wall and that...

Ei

The matrix k is the stiffness matrix of the beam, and S and A are the matrices of member forces and nodal displacements respectively. Equation (3.30) expresses the force-displacement relationships for the beam in the stiffness form as distinct from the flexibility form. The symmetry of the matrix should be noted as consistent with the symmetry exhibited by flexibility coefficients (see page 3 9). EI(02-0,) --M,l Integrating again EI(y2-y,)-EI0,l P, -M Solving equations (3.24) and (3.25) for M,...

Engineering geology environments

A geological environment is the sum total of the external conditions which (nay act upon the situation. For example, a 'shallow marine environment' is all the conditions acting offshore which control the formation of deposits on the sea bed the water temperature, light, current action, biological agencies, source of sediment, sea bed chemistry and so on. The concept of geological environment forms a suitable basis to study systematically the engineering geology of the deposits formed in or...

Examples of hydraulic problems by flow nets

In Figure 9.31(b), let the number of squares along a flow line be n( 15) and the number along an equipotential line be ( 5). Then if the total drop in head is h, the drop in head across each square is h n, and at an imaginary standpipe through the concrete at the sixth equipotential line the loss in head will be The uplift pressure at this point will be the remaining head times the density of water, i.e. Note that this result is independent of the number of squares in the flow net, since if 30...

Ga G J

Where ky and k. are dimensionless form factors depending on the shape of the bar cross-section at each point in the framework. Values of the form factors for some common cross-sections are given in Table 2.9. 4 I-section or hollow rectangle Similarly the internal strain energy of a framework corresponding to the expression in Equation (2.78) is given by For slender bracing and secondary members for which X> 120, the allowable stresses may be divided by (1.6-A 200), giving stresses similar to...

Geological information

Although geological information is available in the form of maps and in written texts and both published and unpublished data may have to be acquired, Military engineering, vol. XV36 suggests the following. Most countries now publish geological maps with supporting literature. This basic literature, which is usually readily available and understandable to a non-geologist, may take the form of a memoir, dealing with the geology of one map sheet or area (or with one aspect of the geology of...

Hydrostatics

(1) A fluid at rest exerts a pressure which is everywhere normal to any surface immersed in it. (2) The pressure intensity at a point P in a liquid is equal to that at the free surface of the liquid together with pgh, where h is the depth of P below the free surface and p is the density of the liquid. In many engineering problems all pressures are treated relative to atmospheric pressure as a datum. Adopting that system, consider the force exerted on an elementary, or infinitesimal, portion SA...

Gzf

Figure A9.1.5 A triaxial cell. (After Clayton, Simons and Matthews (1982) Site investigation. Granada, London) -Prevents ram being pushed out of the chamber when the cell pressure is applied - Stud and wing nuts at 120 or 180 intervals. Drainage saturation (lead can be connected to the top cap) Figure A9.1.5 A triaxial cell. (After Clayton, Simons and Matthews (1982) Site investigation. Granada, London) specimen in various types of test may be consolidated or unconsolidated, drained or...

Jvw

Movement of this screw enables the observer to read, on an auxiliary scale, the lateral shift required in order to bring the image of the main-scale degree graduations into coincidence with the index marks which are built into the optical path. Using this technique it is possible to resolve directly to 20 of arc if the micrometer is reading from one side of the circle. Resolution direct to 1 is possible if a mean-reading optical micrometer is used. In this...

P I P

3.4.3 Assembly of structure stiffness matrix The stiffness method involves the solution of a set of linear simultaneous equations, representing equilibrium conditions, which may be expressed in the form Equation (3.31) is similar in form to Equation (3.23) with the important difference that now we are concerned with a multiple degree of freedom system as distinct from a single unknown displacement. K is the structure stiffness matrix, r is a matrix of nodal displacements and R a matrix of...

Info

Figure 8.25 Examples of particle-size curves of some glacial soils and a London Clay for comparison Figure 8.25 Examples of particle-size curves of some glacial soils and a London Clay for comparison fluvioglacial deposits up to 30 m in thickness. In other areas they exist as thin lenses of limited lateral extent included between layers of till or peat. Deposits of fluvioglacial soils may also occur in river valleys (valley trains) that once served as drainage outlets for glacial meltwater or...

Conic Sections Ellipse Tangent Subnormal Normal Length Property

Figure 1.36 Properties of a conic section Referring to Figure 1.37, F F2 and the foci D,D,, D2D2 the directrices. FVV, Fyv, FVV, F F OFl OF2 e S,V, S,V, S,V, MS, MS, OV, OV2 V,V Let OV, the semi-major axis a and OE the semi-minor axis b, then OF, OF, ae and OS, OS, - also F,P a e.x F2P + i Y F,P+ F,P 2a F,E cOS, a (OE)2 b2 (F,E)2- (OF,)2 a2(I - e2), Hence, as OM x and PM y we have the following. Figure 1.36 Properties of a conic section Figure 1.37 Ellipse in cartesian coordinates Figure 1.37...

Introduction

The work of the land surveyor can be classified into three main areas of responsibility. Firstly, he is concerned with the recording of measurements which allow the size and shape of the Earth to be determined. Secondly, and primarily, he is involved in the collection, processing and presentation of the information necessary to produce maps and plans. Thirdly, he may be required to locate on the surface of the Earth the exact positions to be taken up by new roads, dams or other civil...

Ae

In which the p, system of forces is due to unit tension in the rth redundant member and similarly for p, and p,. The p0 system of forces is that due to the applied load system acting on the statically determinate structure (i.e. with the redundant members omitted). Equations (3.20) and (3.21) should be compared with Equations (3.16) and (3.17) in the flexural case. Example 3.4. The plane truss shown in Figure 3.10 has two redundancies which we will choose as the forces in members AE and EC. AE...

Lnb

1 Standing axis Figure 6.22 Level construction dumpy level Figure 6.24 Coincidence bubble-reading system This type of level is not, as the name suggests, totally automatic. Human intervention is still necessary. However, one major source of human error, that of setting the bubble, is replaced by an automatic compensating system. In common with the tilting level, approximate levelling is still necessary. The tedious and error-prone bubble-setting process, however, is eliminated. As with the...

L S Blake

BSc(Eng), PhD, CEng, FICE, FIStructE Consultant formerly Director of the Construction Industry Research and Information Association Linacre House, Jordan Hill, Oxford OX2 8DP 225 Wildwood Avenue, Woburn, MA 01801-2041 A division of Reed Educational and Professional Publishing Ltd < 3 A member of the Reed Elsevier pic group

Luz

Let the subscripts c and s denote parameters associated respectively with the concrete and the steel. It then follows that (1) The neutral axis is a horizontal straight line passing through the equivalent centroid whose distance c' from the upper boundary of the beam is given by (Note that since Ac and cc are themselves functions of c', Equation (2.125) is an implicit equation.) Example 2.2. A rectangular reinforced concrete beam with a single layer of reinforcement is shown in Figure 2.26. For...

Lwl

Passive earth pressure (divided by factor of safety) Passive earth pressure (divided by factor of safety) Figure 9.21 Dimensions and forces in anchored bulkhead calculation. Earth pressure diagrams illustrated are for homogeneous cohesionless soil. No pressures from surcharge loads have been shown 9.4.6.1 Forces acting on faces of bulkhead The active and passive pressures are first calculated. The active pressure calculations must allow for the maximum possible unbalanced water pressure and for...

M

The plot of MJ, versus x is called the influence line of Ms at P. Thus for the beam AB in Figure 2.20 the influence lines for SJP and MJ, are as shown. The stress resultants are not all independent of each other. Thus considering the rotational equilibrium about the y axis of a small element of a bar subject to a vertical distributed load q per unit length, as in Figure 2.21 These resultants are in equilibrium with the loads acting on that part of the bar which is on the...

M a CO

We apply unit value of each degree of freedom in turn as shown in Figure 3.13(b), (c) and (d). It should be noted that when r, 1 is applied, r2 and r, are constrained at zero value and similarly with r2 1 and r, 1. The force systems necessary to achieve the unit values of the degrees of freedom are also shown at (b), (c) and (d). The equilibrium conditions are clearly in which the subscripts refer to ends 1 and 2. The stiffness expressed in the coordinate system XY2 may be obtained as follows...

Mathematics

The following are true for all values of indices, whether positive, negative or fractional (ap)* a (alb)p aplbF (ab)' a'b' aplaq ap > a p (l a)' ap ps a ap a 1 0P 0 1.1.2 Solutions of equations in one unknown 1.1.2.1 Linear equations Generally ax + b 0 of which there is one solution or root x - b a of which there are two solutions or roots where, if b2> 4ac, the roots are real and unequal, b2 4ac. the roots are real and equal, and b2 < 4ac, the roots are conjugate complex. It is worth...

No Grains Or Sparse Crystals Visible To Naked Eye

Shale (flexible) Slate (brittle) (dull) Serpentine (usually greasy and may be banded) Rocks may contain occasional large crystals embedded in a very fine-grained matrix or occasional very large crystals in a medium-grained matrix - in either case the term 'porphyry' is appended to the rock name, e.g. syenite porphyry. ( + Q) contains numerous white or colourless quartz crystals. ( + B) contains numerous flakes of black mica (biotite). (- Q) contains little or no quartz. ( - B) contains little...

Np

Table 8.10 Effect of air-drying on index properties of a hydrated laterite clay from the Hawaiian Islands (In Gidigasu ((1975) Laterite soil engineering. Elsevier.) Table 8.11 Major landforms as aggregate resources in hot deserts Including peaks, ridges, plateau surfaces, steep (excluding precipitous) slopes,* deep valleys and canyons, wadis, river terraces* and alluvial fans,* bounding scarp slopes.* Forms vary with rock type and the evolutionary history of the area Pediments and alluvial fans...

O

Super 120 90 Zeiss (Ober.) RMK A Normal 60 300 Zeiss (Ober.) RMK A Figure 7.8 Variation in ground coverage of normal, wide and superwide angle cameras Figure 7.8 Variation in ground coverage of normal, wide and superwide angle cameras angle (SWA) lens is its greater ground coverage for a given flying height. This is particularly important since it not only reduces the number of photographs required to cover an area, but also reduces the number of control points which are required for...

O O

(3) Rotate the alidade until the bubble is now approximately perpendicular to the initial position, as shown in Figure 6.7(b). Using footscrew C only, centralize the bubble. (4) Return to the initial position and again centralize the bubble using footscrews A and B. Repeat (2) and (3) until the bubble is central in both positions. (5) Rotate the alidade through 180 until the position shown by Figure 6.7(c) is achieved. If the bubble does not remain in a central position, move the bubble until...

Obm

The reduced level of a point is defined as its height above some datum. In the UK, the fundamental datum established by the Ordnance Survey is mean sea-level at Newlyn, Cornwall, known as Ordnance Datum. A further series of points of known height have been established throughout the UK and these are known as Ordnance bench-marks (OBM). Figure 6.38 Trigonometrical heighting Earth curvature Figure 6.38 Trigonometrical heighting Earth curvature '1 2 2 1 Figure 6.37 Quantity determination using a...

P

Special significance in built-up composite beams, because this stress has to be transmitted between the separate components of the beams by means of suitable bonds such as welds, rivets or shear connectors. Thus consider a beam composed of two materials of Young's modulus E, and E2 respectively comprising areas A, and A2 of the total cross-section (Figure 2.32). The position of the neutral axis and the equivalent moment of inertia of the cross-section are again given by Equations (2.120) and...

Peat And Coal

Figure 8.4 Sedimentary differentiation. (After Read and Watson (1971) Beginning geology, 2nd edn. Macmillan Allen and Unwin, London) changes and convert the sediments into consolidated or lithified (hardened) sedimentary rocks, e.g. a sand becomes a sandstone. 8.2.1.1 Deposition environments and textures of sedimentary rock The characteristics and to a certain extent the engineering performance of recent sediments can be directly related to the environment occurring at their location of...

Photogrammetric instrumentation Photogrammetric instrumentation

Most photogrammetric measurements are recorded from photography produced by a high-quality camera specifically designed for photogrammetric purposes. The main feature which distinguishes this type of camera from others is that the internal geometrical characteristics are known precisely. Thus, data relating to the lens distortion, focal length and principal point location are established, and monitored periodically by a camera calibration procedure. Both aerial and close-range cameras are used...

Plastics and rubbers Terminology

Standard definitions of terms relating to plastics (ASTM D883) includes the following. Polymer A substance consisting of molecules characterized by the repetition (neglecting ends, branch junctions and other minor irregularities) of one or more types of monomelic units. Plastic(s) A material that contains as an essential ingredient one or more organic polymeric substances of large molecular weight, is solid in its finished state and, at some stage in its manufacture or processing into finished...

Principles of photogrammetry

Since measurements may be taken from both air and ground images (normally photographs) two separate branches of the discipline are generally recognized aerial and close range (or terrestrial) photogrammetry. Aerial photogrammetry is a well-established technique in civil engineering for the production of topographic maps. Aerial photographs produced for such purposes can be obtained either with the optical axis of the camera pointing, nominally, vertically downwards so producing vertical aerial...

Qr

( Ty cubical block resting on the bed Resistance to overturning about P (p' -p)l' 2 g Resistance to sliding fi(p'-p)Pg where p is the coefficient of sliding friction. Force of impact of stream against face RS K'pi J v2 d y where K' is a coefficient, 0.70, to allow for the fact that not all the forward momentum of the stream is 'destroyed'. Therefore, block will overturn if These results neglect other effects such as reduction of pressure on top and lee faces. They serve to show, however, that...

References

W. (1954) 'The pore pressure coefficients A and B Geotechnique, 4, 143. 2 Bishop, A. W. and Henkel, D. J. (1957) The measurement of soil properties in the triaxial test. Edward Arnold, London. 3 Taylor, D. W. (1948) Fundamentals of soil mechanics. Wiley, New York. 4 Terzaghi, K. and Peck, R. B. (1967) Soil mechanics in engineering practice. Wiley, New York. 5 Loudon, A. G. (1952) 'The computation of permeability from simple soil tests', Geotechnique, 3, 165. 6 Gibson, R. E. and...

River With Channel Deposits

Figure 8.30 Deposits in the floodplain of a river Figure 8.30 Deposits in the floodplain of a river Figure 8.31 Long profiles of rivers with down-cutting and aggradation phases associated with changing sea-levels. Fine dots, alluvium of temperate stages large dots, sands and gravels of cold stages a, preglacial valley, river rejuvenated by low sea-level of glacial times. Nick-point marks the head of rejuvenation N b, aggradation as a result of a rising interglacial sea-level c, a further...

Rock deformation in Nature fractures and folds

When rocks of the Earth's upper mantle are subject to large stresses, they either break or bend with the production of fractures or folds. The kind of structure formed depends on the condition of the rocks and the rate at which deformation takes place. Most rocks are brittle at surface conditions and tend to fracture under stress though they may yield slowly by bending. At deeper levels where temperatures and pressures are high the majority of rocks become ductile and deform without breaking....

Rock tests

Table 10.4 illustrates the various categories of testing, currently presented as Suggested methods by the ISRM.24 Tests for classification and characterization of rock (index tests) are used for rock quality description and mapping and are generally quick and relatively cheap. Also, proposed construction methods can be evaluated from index test results, for example abrasiveness and hardness are relevant to tunnelling machine Table 10.3 Glossary of in situ stress terms. (After Hyett, Duke and...

Stability analysis

Slope stability problems in engineering works are usually analysed using limit equilibrium methods. Many such methods are available in practice and the most common ones call on the principle of slices. In this method, the failure mass is broken up into a series of vertical slices and the equilibrium of each of these slices is considered. This procedure allows both complex geometry and the variable soil and pore pressure conditions of a given problem to be considered. The methods most commonly...

Surveying instrumentation

Surveying is essentially concerned with the direct measurement of three fundamental quantities (1) the angle subtended at a point (2) the distance between two points and (3) the height of a point above some datum, normally mean sea-level. From the measurement of these three quantities, it is then possible to compute the three-dimensional positions of points. With the exception of electronic methods of determining distance, the instruments used by the surveyor have not radically changed in...

T

. 5 . , , du, , , du, . du dx + dy + dz where the differentials dux, duy and du, are the differences between the components of u at the two points. As such, these differentials can be regarded as the components of the vector giving the displacement of P* relative to P. In order to obtain a concise description of the deformation of the material at P it is convenient to define nine dimensionless components eyy, 8 , exy, , coxy, coyz, to by the following equations, called the strain-displacement...

The basics of soil behaviour

In engineering terms, soil is the generally softer, weaker and more weathered material overlying rock. All soils consist of solid particles assembled in a relatively loose packing. The voids between the particles may be filled completely with water (fully saturated soils) or may be partly filled with water and partly with air (partly saturated soils). Soil and rock materials can, very simply, be divided into the groups shown in Table 9.1. The primary engineering problems which we attempt to...

The stability of slopes

The analysis of slopes is important because of the dangers to both structures and life that can be caused by two types of problem (1) Where construction or excavation causes stress changes in the soil which lead to failure in previously stable ground (the so-called 'first-time slide'). (2) Where construction or excavation reactivates movement on a pre-existing shear surface in the soil, usually part of an ancient and pre-existing landslide. As with other areas of soil mechanics, an important...

The use of photogrammetry in civil engineering

The use of aerial survey is generally considered to be the standard method of producing a topographic map or plan at scales smaller than 1 500. For scales greater than 1 500, ground survey would almost invariably be used. The basic sequence of operations required for the production of a topographic map is shown by the flow diagram in Figure 7.17. The major air survey companies will have the equipment and manpower to carry out all the stages indicated but smaller concerns might, for example,...

The use of remote sensing in civil engineering

Although aerial and satellite remote-sensing imagery (other than black-and-white aerial photography) have been used for topographic mapping, the primary role of this type of imagery has been for the production of thematic maps. Generally, for such applications users are satisfied with a relatively low level of positional accuracy and are also willing to accept a lower level of completeness than is the case with topographic maps. The type of remote-sensing data which is appropriate will depend...

Pjb

In the case of a distributed load which has a length greater than the span, then for an influence line of type (b) in Figure 3.19, the whole span would be loaded, whereas for an influence line of type (c) one would place the left-hand end of the load at X thus avoiding the introduction of a negative effect on the maximum positive value. For a short distributed load, as at (h), for maximum effect at y, the load must be placed so that the shaded area in (j) is a maximum. or, if the unit load lies...

Preliminary assessment

Site investigation in the overall sense is the process by which the various factors influencing the selection and use of the most appropriate location for a project are evaluated. Identification of the primary factors aids the initial selection of the site. Thus whereas topography and the geology determine the site of a dam, minimal environmental pollution requirements often define the location of an airport and preferential government aid that of a new industrial development. Each of the...

Seepage and flow nets

A flow net is a graphical representation of the pattern of the seepage or flow of water through a permeable soil. It is possible, by means of a flow net, to calculate the hydrostatic uplift on a structure such as a dam or barrage, the amount of seepage It is common practice to start the analysis by assuming a uniform distribution off(x) (say (.*) 1.0) across the slip. Some authors have indicated that variations in the shape of the f(x) distribution have little effect on the factor of safety...

Flow Chart For Slope Stability In

Figure 10.13 An illustration of the size-dependence of shear stress-deformation behaviour for nonplanar joints. (After Bandis, Lumsden and Barton (1981) 'Experimental studies of scale effects on the shear behaviour of rock joints'. Int. J. Rock Mech. Min. Sci., 18) The analysis of a rock structure should not start without first preparing a complete statement of the factors involved. These usually include the geometry and intended purpose of the structure together with the main elements of the...

Principle Of Stadia Method

Figure 6.9 Optical distance measurement ODM spaced either side of it. These stadia lines define the fixed parallactic angle. If the theodolite telescope is sighted on to a levelling staff and the readings of the outer lines noted, the difference in the readings, the staff intercept s , will be directly proportional to the horizontal distance between the instrument and the staff. Generally, the distance between the stadia lines is designed in such a manner that the horizontal distance Z gt H...

Standards and codes of practice referred to in Chapter

BS 12 1978 Specification for ordinary and rapid-hardening Portland cement. BS 146 1973 Part 2 Specification for Portland blast-furnace cement. BS 812 1984 Part 101 Guide to sampling and testing aggregates. BS 877 1973 1977 Part 2 Specification for foamed or expanded blast-furnace slag lightweight aggregate for concrete. BS 882 1983 Specification for aggregates from natural sources for concrete. BS 915 1972 1983 Part 2 Specification for high alumina cement. BS 1014 1975 1986 Specification for...

Hydrodynamics

Arbitrarily chosen datum of potential Figure 5.17 Mass of liquid subjected to p N m2 and moving with velocity v m s A liquid possesses energy by virtue of the pressure under which it exists, its velocity and its height above some datum level of potential energy. These three forms of energy pressure, kinetic and potential may be expressed as quantities per unit weight of the liquid concerned. The result is the pressure, kinetic or potential head. Thus, referring to Figure 5.17, in which a mass...