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...

Jfx

777 77777777y 777777 W7 Diagrammatic equivalent of (a) (b) If v is the velocity through the siphon, then loss at entry + friction loss + loss at exit, i.e. H 0.80(a2 2g) + friction loss + (v2 2g) for submerged sharp entrance and exit ends of pipe. The end-effects are negligible in a reasonably long pipe. Let F, be the friction loss of head in portion A'B of length ,. Then pressure head at crown B is assuming a loss of 0.80(t> 2 2g) at A'. Hence pK is negative, i.e. less than atmospheric. In...

Sdr

Figure 1.14 Solution of trigonometrical equations showing the intersection between x 10 and x n as x 169 approximately 1.2.12 Solution of trigonometric equations The method best suited to the solution of trigonometric equations is that described in the section on algebra which deals with the method of solving transcendental equations by means of graphs. The expression to be solved is arranged as two identities and two graphs drawn as shown in Figure 1.14. The points of intersection of the...

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 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

Great circle The section of a sphere cut by a plane through any diameter, e.g. ACBC'. Poles Poles of any circular section of a sphere are the ends of a diameter at right angles to the section, e.g. D and D' are the poles of the great circle ACBC'. Lunes The surface areas of that part of the sphere between two great circles there are two pairs of congruent areas, e.g. ACA'C'A CBC'B'C and ACB'C'A A'CBC'A'. Area oflune If the angle between the planes of two great circles forming the lune is 9...

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,...

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 +...

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 evaluation of Equation (3.16) requires the integration of the product of two bending moment distributions over the complete structure. Such distributions can generally be represented by simple geometrical figures such as rectangles, triangles and parabolas and standard results can be established in advance. Table 3.3 gives values of product integrals for a range of combinations of diagrams. It should be noted that in applying Equation (3.16) in this way, the flexural rigidity EI is assumed...

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...

F

Among the topics deserving of (1) Use of the principle of virtual work in obtaining relationships between applied loads and plastic moments of resistance. (2) Effects of strain hardening. (3) Evaluation of shape factors for various cross-sections. (4) Application of the maximum principle in obtaining lower bounds. (5) Numbers of independent mechanisms. (8) Moment carrying capacity of columns. (9) Behaviour of welded connections. 1 Jenkins, W. M (1982)...

Fb

Construction Industry Research and Information Association (CIRIA), 6 Storey's Gate, London SW1P 3AU. Copper Development Association, Orchard House, Mutton Lane, Potters Bar, Herts EN6 3AP. Flat Glass Council, 44 48 Borough High Street, London SEI 1XB. Institution of Mining and Metallurgy, 44 Portland Place, London WIN 4BR. Lead Development Association, 34 Berkeley Square, London W1X 6AJ. National Physical Laboratory, Teddington, Middlesex TW11 0LW. Paint Research Association, Waldegrave Road,...

Ga

2.3.12 Note on the limitations of the engineering theory of the bending of beams (ETBB) As noted in section 2.3.6, the basic assumptions of the ETBB, while quite correct when the beam is subject to pure bending, become invalid when the beam is also subject to shear. In particular, we can no longer assume that plane sections remain plane. Some indication of the error involved in using the ETBB is obtained by analysing a thin-walled deep cantilever beam. Treating this as a plane stress problem, a...

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...

HT[ihl

Let PQ in Figure 1.27 represent an elemental length ds of a given curve and PS, QT the tangents at the points P, Q then Curvature at P dfj ds. For a circle centre at C, radius p. ds pdji, i.e. curvature I p. Therefore p radius of curvature (1.29) Putting tan 1 and differentiating

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...

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...

Sir

Figure 7.1 Relief and tilt image displacements on a vertical and near-vertical aerial photograph The effect of image displacement on scale can be seen in Figures 7.2 and 7.3 which illustrate the separate results of tilt and variation in ground relief. It can be seen that, unlike a map which has a constant scale, the combined effects of relief and tilt produce a photograph which will be of constantly changing Figure 7.2 Scale changes on a vertical aerial photograph caused by variations in the...

Ik

If the length of a bar is greater than about 5 times its lateral dimensions, it can become unstable under compressive forces. Consider, for example, the pin-ended bar subject to an axial compressive force F shown in Figure 2.50. If u. is the lateral displacement in the z direction of a particular cross-section, then the moment My exerted by F at the section is Fu Thus from Equation (2.146) we have the differential equation Note that if the location of the neutral axis is known, then the maximum...

Info

* Flame retardant grades are available F Flammable and continues lo burn after ignition B Combustible but self-extinguishing R Resistant to ignition * Flame retardant grades are available F Flammable and continues lo burn after ignition B Combustible but self-extinguishing R Resistant to ignition nants, washing with a detergent solution followed by thorough rinsing is preferable to solvent washing, which tends to spread the contaminant rather than remove it. Weld slag and fume may be removed by...

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

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...

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...

N

The dumpy level was so named because of the rather short telescopes which were used with early versions of this instrument. The construction of a typical dumpy level is shown in Figure 6.22. The most distinctive feature of this type of level is that the axis of the telescope is fixed rigidly to the standing axis of the instrument. In order to satisfy the condition that both the vertical and standing axes are coincident, the standard levelling procedure outlined in section 6.2.1.3 is carried...

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...

Oxford Auckland Boston Johannesburg Melbourne New Delhi

First published as Civil Engineering Reference Book 1951 Reprinted 1995 (twice), 1997, 1998, 2000, 2001 Reed Educational and Professional Publishing Ltd 1989 All rights reserved. No part of this publication may be reproduced in any material form (including photocopying or storing in any medium by electronic means and whether or not transiently or incidentally to some other use of this publication) without the written permission of the copyright holder except in accordance with the provisions of...

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...

Physical properties of water Density

For most purposes in hydraulic engineering, the density of fresh water may be taken to be 1000 kg m3. Correspondingly, the weight of 11 is approximately 1 kg. In more precise work, usually of a laboratory or experimental nature, the variation of density with temperature may have to be taken into account in accordance with Table 5.1. Table 5.1 Density of fresh water at atmospheric pressure Table 5.1 Density of fresh water at atmospheric pressure

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...

Q CDbd[ VM[irf d

Where b2 is the breadth at throat, d2 the depth at throat, dx the depth upstream of the constriction, bx the breadth upstream of the constriction, and CD is the coefficient of discharge. For particular designs, CD is best found by scale-model experiments. Details as to proportions, shapes and types of flow may be found in papers by Engel.29 See also Elsden.30 ' Area ac at - . . J vena contracta Consideration of various published data31 indicates that for orifices of 6.35 cm diameter or over,...

Q

Of carrying capacity must depend not only upon the material but also upon the nature and velocity of the water and upon the diameter of the pipe an increased roughness due to tubercula-tion will be more troublesome, proportionately, in small- than in large-diameter pipes.10 5.3.8 Use of additives to reduce resistance The literature dealing with this important subject has expanded greatly in the last 10 or 20 years and now includes a large number of papers giving information not only of...

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...

R

In practice, the slopes of beams are extremely small and the denominator of the right-hand side of Equation (2.145) can be taken to be equal to unity, whence, combining Equations (2.119) and (2.145) gives the following differential equation called the differential equation of beams. For statically determinate beams, where My can be found as a function of x, this second-order equation can be solved subject to boundary conditions by double integration. The solution u.(x) is then the deflected...

R ygm i LlwsAJ

Let Q (constant) discharge (volume s) supplied to the channel. Example 5.11. The following example illustrates the application of the backwater function. A dam is built across a stream which was previously flowing with a depth of 1 m. The effect of the dam is to raise the level just behind it by 4 m. The slope of the bed is 1 2000 and 0.01. What is the effect of the dam on the levels upstream (Figure 5.43.) 1 2000 2 1 10 H 1 m H( -2 ) 0.9 h2 depth behind dam 5 m y2 h2 H 5 tf> (y2) 0.927

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 stress

The state of in situ stress refers to the stresses which exist naturally in a rock mass prior to any influence from engineering works. These stresses arise from gravitational and tectonic movements, crustal cooling and other major geomorphological influences. Complex stresses can develop in steep mountainous areas and near deeply incised river valleys. Given these possible origins, the state of in situ stress of a rock mass cannot readily be predicted and values can only be reliably obtained by...

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

The ratio Zp Zt is the shape factor of the cross-section. Thus the shape factor for a rectangular cross-section is 1.5. The shape factor for an I-section, depth d and flange width b, is given approximately by where x and and t, are the web and flange thicknesses respectively Values of plastic section moduli for rolled universal sections are given in steel section tables. The definition of collapse, which follows from the assumed basic stress-strain relationship of Figure 3.29, has already been...

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 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...

Tz

Iy (ji 4)6a5 0.78546a3 I, (7i 4)aA3 0.7854a63 2.17. Then the inertias Iy., and ,, , being defined in the same way as y, 2 and in Equations (2.94 to 2.96), are related to ,, I, and by the equations , i( , + A) + - A) cos (2a) - sin (2a) (2.101) , *( , + A) - - J cos (2a) + lyl sin (2a) (2.102) I,, i(Iy ,) sin (2a) + Iyz cos (2a) (2.103) Note that these transformation equations are similar in form to the transformation equations of plane stress in Equations (2.17 to 2.19), the difference being in...

Xkj

Melting ta form magma and igneous .rocks Pltnklon T Sediment j_ Magmj riling to form new ocean floor crust Figure 8.1 Diagrammatic representation of the long-term cycling of rocks. (After Bradshaw, Abbot and Gelsthorpe (1978) The Earth's changing surface. Hodder and Stoughton, London) and erosion took place. The sea floors with their sediments were raised and became subject to erosion by wind and water. There were also periods of quiet sedimentation, when seas covered the land, and intervening...

W M P

It is seen that 2I and fl2 are numerically equal, a result which could be established using the Reciprocal Theorem. This is a useful property since in general f f and the effect is to reduce the number of separate calculations required. It should be further noted that whilst 2, ,2, 2l is an angular displacement and 12 a linear displacement. The evaluation of the flexibility coefficients provides the displacements at selected points in the structure due to unit values of the associated,...

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...

Q O

Figure 9.14 Variation of strain influence factor with depth. (After Schmertmann (1970) 'Static cone to compute elastic settlement over sand', Proc. Am. Soc. Civ. Engrs, 98 Simons and Menzies (1977) A short course in foundation engineering. Butterworths, London) The problem of earth pressure is the oldest soil mechanics problem. Active pressure is the lowest pressure which a retaining structure must be capable of resisting in order to prevent a soil mass from collapsing. The highest pressure...

Materials

4.1 Introduction 4 3 4.1.1 Standards and codes of practice 4 3 4.2.4 Concrete mix design 4 8 4.2.5 Properties of hardened concrete 4 9 4.2.7 Concreting in hot, arid climates 4 14 4.2.8 Reinforcement and prestressed steel 4 14 4.3.1 Workability tests 4 14 4.3.3 Accelerated strength tests 4 16 4.3.5 Nondestructive strength tests 4 16 4.3.6 Tests on aggregates 4 16 4.3.7 Measurement of entrained air 4 17 4.3.8 Analysis of fresh concrete 4 17 4.3.9 Analysis of hardened concrete 4 17 4.4 Plastics...

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...