Engineering Rock Mechanics
68 In situ stress discontinuities at various scales. Naturally, the zone of influence of a discontinuity will depend on its size ...
Glossary of terms related to stress states in rock masses 69 Palaeostress. A previously active in sifu stress state which is no ...
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5 Strain is a change in the relative configuration of points within a solid. One can study finite strain or infinitesimal strain ...
72 Strain Figure 5.1 Large displacements around an originally arch-shaped coal mine access tunnel (from Pan, 1989). grasp the co ...
Examples of homogeneous finite strain 73 I- t- 1 4 4.7 ---I!- I' 4 Contraction positive Q Q' I P,P' Negative shear- strain: P'Q' ...
74 Strain especially in terms of the perhaps unexpected relation between the shear modulus and Young’s modulus and Poisson’s rat ...
Infinitesimal strain 75 =acm L: : :1 Figure 5.6 The general transformation of a two-dimensional shape using homogeneous co-ordin ...
76 Strain ir (x + u,, y + UY' z + u.) + dx + ux*. + dy + uy*, + dz + uz* 2 Figure 5.7 Change in co-ordinates as a line PQ is str ...
The strain tensor 77 First, we should note that the term y,, i.e. 2a, is known as the engineering shear strain, whereas the term ...
78 Strain The transformation properties of the strain matrix allow us to determine the complete in situ or laboratory strain ten ...
The elastic compliance matrix 79 &.IT = sll% + S12qyy + s13°ZZ + s142xy + s152yz + S16Tzzx Eyy = s21% + '22Oyy + '23Ozz + s% ...
80 Strain Direct coupling of all normal components Indirect coupling of normal Coupling of normal and shear components component ...
The elastic compliance matrix 81 Such a material could arise from the microstructure of the intact rock, or in the case of rock ...
82 Strain Note that, because we now have complete isotropy, the subscripts can be dispensed with, the shear modulus G is implici ...
Implications for in situ stress 83 and for orthotropy (T,, = The reader should note that, in order to simplify these relations, ...
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6 Intact rock Having introduced the concepts of stress and strain, we can now consider how the rock reacts to given loads. It is ...
86 Intactrock the corners and edges of rock blocks which have been disturbed by the process of excavation. Thus, the deformabili ...
The complete stress-strain curve in uniaxial compression 87 -_ __ = Young’s modulus b Residual strength do Zero at peak strength ...
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