土木岩土地质工程专业外文翻译原文和译文

土木岩土地质工程专业外文翻译原文和译文内容摘要：

iables: such a macroscopic failure condition simply bees where it will be assumed that A convenient representation of the macroscopic criterion is to draw the strength envelope relating to an oriented facet of the homogenized material, whose unit normal n I is inclined by an angle a with respect to the joint direction. Denoting by n and n the normal and shear ponents of the stress vector acting upon such a facet, it is possible to determine for any value of a the set of admissible stresses ( n , n ) deduced from conditions (3) expressed in terms of ( 11 , 22 , 12 ). The corresponding domain has been drawn in Fig. 2 in the particular case where m . 某某某 大学毕业设计（论文） Two ments are worth being made: 1. The decrease in strength of a rock material due to the presence of joints is clearly illustrated by Fig. 2. The usual strength envelope corresponding to the rock matrix failure condition is ‘‘truncated’’ by two orthogonal semilines as soon as condition mj HH  is fulfilled. 2. The macroscopic anisotropy is also quite apparent, since for instance the strength envelope drawn in Fig. 2 is dependent on the facet orientation a. The usual notion of intrinsic curve should therefore be discarded, but also the concepts of anisotropic cohesion and friction angle as tentatively introduced by Jaeger (1960), or Mc Lamore and Gray (1967). Nor can such an anisotropy be properly described by means of criteria based on an extension of the classical MohrCoulomb condition using the concept of anisotropy tensor(Boehler and Sawczuk 1977。 Nova 1980。 Allirot and Bochler1981). Application to Stability of Jointed Rock Excavation The closedform expression (3) obtained for the macroscopic failure condition, makes it then possible to perform the failure design of any structure built in such a material, such as the excavation shown in Fig. 3, where h and β denote the excavation height and the slope angle, respectively. Since no 某某某 大学毕业设计（论文） surcharge is applied to the structure, the specific weight γ of the constituent material will obviously constitute the sole loading parameter of the the stability of this structure will amount to evaluating the maximum possible height h+ beyond which failure will occur. A standard dimensional analysis of this problem shows that this critical height may be put in the form where θ=joint orientation and K+=nondimensional factor governing the stability of the excavation. Upperbound estimates of this factor will now be determined by means of the yield design kinematic approach, using two kinds of failure mechanisms shown in Fig. 4. Rotational Failure Mechanism [Fig. 4(a)] The first class of failure mechanisms considered in the analysis is a direct transposition of those usually employed for homogeneous and isotropic soil or rock slopes. In such a mechanism a volume of homogenized jointed rock mass is rotating about a point Ω with an angular velocity ω. The curve separating this volume from the rest of the structure which is kept motionless is a velocity jump line. Since it is an arc of the log spiral of angle m and focus Ω the velocity discontinuity at any point of this line is inclined at angle wm with respect to the tangent at the same point. The work done by the external forces and the maximum resisting work developed in such a mechanism may be written as (see Chen and Liu 1990。 Maghous et al. 1998) 某某某 大学毕业设计（论文） where ew and mew =dimensionless functions, and μ1。