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...

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,...

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...

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 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...

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...

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...

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...

Ei

And the solutions are pt, _ Wab (2a+ 7fc) The actual bending moment distribution may now be determined by the addition of the three systems, i.e. the applied load and the two redundants. The general expression is and the bending moment under the load W is The final bending moment diagram is shown in Figure 3.8(h). Example 3.3. A portal frame ABCD is shown in Figure 3.9(a). The frame has rigid joints at B and C, a fixed support at A and a hinged support at D. The flexural rigidity of the beam is...

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...

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...

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

Geological Joints

10.1 The scope of rock mechanics and rock engineering Rock mechanics is a term for science and engineering applied to rock masses. As such, the term has relevance in numerous fields such as the recovery of hydrocarbons in rock reservoirs, development of geothermal energy resources, studies of the Earth's crust, seismicity studies, as well as mining and civil engineering. The area of activity restricted to construction works which require or essentially comprise excavation into the surface of,...

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...

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...

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...

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...

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...

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...

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...

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...