摘要
岩体具有复杂的构造层次,这种构造层次可以从原子尺度水平一直延伸到地质构造水平。这种情况使连续介质力学中使用的基本体元的概念及圣维南变形协调条件受到了置疑。内部构造层次影响岩体的粘性及动力强度。但到目前为止还没有看到连接微细宏观层次上粘性及动力强度的研究。基于已有的资料及物理力学理论对材料的粘性及构造层次之问的关系进行了系统研究。由研究可以看出，不同的构造层次对应着不同的强度、粘性及应变率。宏观层次通常对应着低的强度、低的应变率及高的粘性系数，而微细观层次对应着高的强度、高的应变率及低的粘性系数。通常随着外载的增加，变形速度的增大，发生变形与破坏的层次逐渐由宏观经由细观逐步向微观层次过渡，动力强度增加，粘性系数逐渐降低。在中高应变速率区，岩石的强度增加很大，而粘性与变形速率成反比。因此，强度及粘性系数对于一种介质来讲不是常数，而是在不同的构造层次上具有不同的大小。表现在破坏块体的尺寸上，最小的破坏尺寸与所能达到的强度有直接的关系。通过不同层次上岩体的力学行为的分析，建议了强度、粘性对于构造层次及应变率的依赖关系及岩体破坏块体尺寸的确定公式。
Rock mass posses complex structural hierarchy. Such structural hierarchy involves a very wide range of scale levels from atomic scale level to tectonic scale level. This situation makes the concept of elementary volume and Saint-Venant＇s deformation compatibility condition used in continuum mechanics problematic. Internal structural hierarchy influences viscosity and dynamic strength of rock mass, but until now studies haven＇t been seen to link viscosity and dynamic strength of rock mass on different scale levels. This paper, based on the available investigation data and physical mechanical theories, studied the relationship between the viscosity, dynamic strength and the structure hierarchy of rock mass. It is shown from the study that different hierarchy levels correspond to different strength, viscosity and deformation rate. Macroscopic hierarchy scale level corresponds to low strength, low deformation rate and high viscosity, micro-macroscopic scale levels share high strength, high deformation rate and low viscosity. Generally, with the increase of the external loads and the deformation rate, the deformation and fracture consecutively involve macro-, meso-and microscopic levels, correspondingly dynamic strength increases, and viscosity decreases gradually. In moderate and high deformation rate region, dynamic strength increases substantially; viscosity is inversely proportional to deformation rate. Hence strength and viscosity are not constants for one material, but have different values on different hierarchy levels. As for the size of fractured rock, it is related with the dynamic strength which rock mass can reach. Based on the analysis of mechanical behavior of rock mass on different hierarchy levels, approximation formulae for the dynamic strength and viscosity in dependence on hierarchy levels and deformation rate, formula for the determination of fractured rock mass are suggested.
出处
《岩石力学与工程学报》
EI
CAS
CSCD
北大核心
2005年第A01期4679-4687,共9页
Chinese Journal of Rock Mechanics and Engineering
基金
国家自然科学基金重大项目（50490275）
关键词
岩土力学
构造层次
粘性
松弛
动力强度
rock and soil mechanics
structural hierarchy, viscosity
relaxation
dynamical strength
