1、外文翻译 Problems 1 From the data given in figure 4.18,calculate the tangent modulus and Poissons ratio for the initial elastic behavior of limestone with3= 2.0MPa. 2 A porous sandstone has a uniaxial compressive strength of c=75MPa. the results of a series of triaxial compression tests plotted on shear
2、 stress-normal stress axes give a linear Coulomb peak strength envelope having a slope of 45o Determine the axial stress at peak strength of a jacketed specimen subjected to a confining pressure of 3= 10MPa. If the jacket had been punctured during the test and the pore pressure had built up to a equ
3、al to the confining pressure ,what would the peak axial stress have been? 3(a) Establish an approximate peak strength envelope for the marble for which the date shown in Figure 4.19 were obtained. 3(b)In what ways might the observed stress-strain behavior of the specimens have differed had the tests
4、 been carried out in a conventional testing machine having a longitudinal stiffness of 2.0 GNm-1? Assume that all specimens were 50mm in diameter 100mm long. ROCK STRENGTH AND DEFORMABILITY 4 A series of laboratory tests on intact specimens of quartzite gave the following mean peak strengths. The un
5、its of stress are MPa, and compression is taken as positive. 31 21 31 -21 triaxial compression 100 100 135 130 160 150 200 180 2=3 298 248 435 335 biaxial tension/ compression 1 2 3 0 0 0 -13 -13.5 218 50 -13 225 100 0 228 150 0 210 210 0 Develop a peak strength criterion for the quartzite for use i
6、n underground excavation design. Experience has shown that in situ uniaxial compressive strength of the quartzite is one-half the laboratory value. 5A series of triaxial compression tests on specimens of a slate gave the following results: Confining pressure 3(MPa) Peak axial stress 1(MPa) Angle bet
7、ween cleavage and1 o 2.0 5.0 10.0 15.0 20.0 62.0 62.5 80.0 95.0 104.0 40 32 37 39 27 In each test ,failure occurred by shear along the cleavage. Determine the shear strength criterion for cleavage plans. 6 In a further series of tests on the slate for which the data of Problem 5 were obtained, it wa
8、s found that, when failure occurred in directions other than along the cleavage, the peak strength of rock material was given by 1=150+2.83 where 1 and 3 are in MPa. Construct a graph showing the expected variation of peak axial stress at a confining pressure of 10 MPa, as the angle between the clea
9、vage and the specimen axis varies from 0oto90o. 7 The following results were obtained in a series of direct shear tests carried out on 100 mm square specimens of granite containing clean, rough, dry joints. Normal stress Peak shear strength Residual shear strength Displacement at peak shear strength
10、 Normal Shear n(MPa) p(MPa) r(MPa) (mm) (mm) 0.25 0.25 0.15 0.54 2.00 0.50 0.50 0.30 0.67 2.50 1.00 1.00 0.60 0.65 3.20 2.00 1.55 1.15 0.45 3.60 3.00 2.15 1.70 0.30 4.00 4.00 2.60 0.15 4.20 (a) Determine the basic friction angle and the initial roughness angle for the joint surfaces. (b) Establish a peak shear strength criterion for the joints, suitable for use in the range of normal stresses, 0-4MPa. (c) Assuming linear shear stress-shear displacement relations to peak shear strength， investigate the influence of normal stress on the shear stiffness of the joints.
