土木工程岩土工程裂隙岩体毕业论文中英文资料对照外文翻译文献综述
criterion, and those obtained by means of a computer code based on the distinct element method. It is shown that, while both methods lead to almost identical results for a densely fractured rock mass, a ‘‘size’’ or ‘‘scale effect’’ is observed in the case of a limited number of joints. The second part of the paper is then devoted to proposing a method which attempts to capture such a scale effect, while still taking advantage of a homogenization technique. This is achieved by resorting to a micropolar or Cosserat continuum description of the fractured rock mass, through the derivation of a generalized macroscopic failure condition expressed in terms of stresses and couple stresses. The implementation of this model is nally illustrated on a simple example, showing how it may actually account for such a scale effect.
Problem Statement and Principle of Homogenization Approach
The problem under consideration is that of a foundation (bridge pier or abutment) resting upon a fractured bedrock (Fig. 1), whose bearing
capacity needs to be evaluated from the knowledge of the strength capacities of the rock matrix and the joint interfaces. The failure condition of the former will be expressed through the classical Mohr-Coulomb condition expressed by means of the cohesion Cm and the friction angle m . Note that tensile stresses will be counted positive throughout the paper.
Likewise, the joints will be modeled as plane interfaces (represented by lines in the gure’s plane). Their strength properties are described by means of a condition involving the stress vector of components (σ, τ) acting at any point of those interfaces
According to the yield design (or limit analysis) reasoning, the above structure will remain safe under a given vertical load Q(force per unit length along the Oz axis), if one can exhibit throughout the rock mass a stress distribution which satis es the equilibrium equations along with the stress boundary conditions,while complying with the strength requirement expressed at any point of the structure.