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英语翻译
One of the most critical steps in any limit equilibrium analysis is the determination or the estimation of the shear strength parameters (c and φ) for the surface along which it is anticipated that sliding will take place.In the case of this slope on Sau Mau Ping Road,no information on shear strength was available at the time of the initial studies and so estimates had to be made on the basis of published information for similar rocks.
Hoek and Bray (1974) published a plot,reproduced in Figure 7.8,of cohesive strengths and friction angles for rocks and soils,based upon the results of published Estimates of shear strength back analysis of slope failures.Superimposed on this plot is an elliptical zone which
encompasses the estimated range of shear strength for sheet joints in unweathered granite.In choosing this range it was considered that the friction angle φ probably ranges from 30° for very smooth planar surfaces to 45° for rough or partly cemented surfaces.The cohesive strength c is more difficult to estimate and the range of 0.05 to
0.2 MPa was chosen on the basis of the results of back-analyses of slope failures,plotted in Figure 7.8.
Figure 7.8:Relationship between friction angles and cohesive strengths mobilised at failure of slopes in various materials.The plotted points were obtained from published information from the back analysis of slope failures.(After Hoek and Bray 1974).
Some readers may be surprised that a cohesive strength has been assumed for joint surfaces which obviously have no tensile strength or ‘stickiness’ as would be found in a clayey soil.In fact,this assumed cohesive strength is defined by the intercept,on the shear strength axis,of a tangent to a curvilinear Mohr envelope.This curvature is the result of the interlocking of asperities on the matching surfaces of the joints and
the increase in shear strength given by this interlocking plays a crucial role in the 100 Chapter 7:A slope stability problem in Hong Kong stability of slopes such as that under consideration in this chapter.A full discussion on the shear strength of discontinuities in rock masses is given in Chapter 4.
One of the most critical steps in any limit equilibrium analysis is the determination or the estimation of the shear strength parameters (c and φ) for the surface along which it is anticipated that sliding will take place.In the case of this slope on Sau Mau Ping Road,no information on shear strength was available at the time of the initial studies and so estimates had to be made on the basis of published information for similar rocks.
Hoek and Bray (1974) published a plot,reproduced in Figure 7.8,of cohesive strengths and friction angles for rocks and soils,based upon the results of published Estimates of shear strength back analysis of slope failures.Superimposed on this plot is an elliptical zone which
encompasses the estimated range of shear strength for sheet joints in unweathered granite.In choosing this range it was considered that the friction angle φ probably ranges from 30° for very smooth planar surfaces to 45° for rough or partly cemented surfaces.The cohesive strength c is more difficult to estimate and the range of 0.05 to
0.2 MPa was chosen on the basis of the results of back-analyses of slope failures,plotted in Figure 7.8.
Figure 7.8:Relationship between friction angles and cohesive strengths mobilised at failure of slopes in various materials.The plotted points were obtained from published information from the back analysis of slope failures.(After Hoek and Bray 1974).
Some readers may be surprised that a cohesive strength has been assumed for joint surfaces which obviously have no tensile strength or ‘stickiness’ as would be found in a clayey soil.In fact,this assumed cohesive strength is defined by the intercept,on the shear strength axis,of a tangent to a curvilinear Mohr envelope.This curvature is the result of the interlocking of asperities on the matching surfaces of the joints and
the increase in shear strength given by this interlocking plays a crucial role in the 100 Chapter 7:A slope stability problem in Hong Kong stability of slopes such as that under consideration in this chapter.A full discussion on the shear strength of discontinuities in rock masses is given in Chapter 4.
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