含优势断续节理组的工程岩体等效遍布节理模型强度参数研究

岩体经历的成岩和构造改造等作用通常使其优势节理组发育，使得工程岩体呈现各向异性特征。本文首先说明当大尺度工程岩体含断续节理组时，岩桥对各向异性强度特征的影响突出。进而指出在采用遍布节理模型描述含优势随机节理的岩体各向异性时，模型中结构面参数为贯通节理的参数，不能直接采用现场断续节理的测试结果，需要进行大尺度岩体各向异性参数等效。然后，提出基于连续方法FLAC3D遍布节理的参数变化吻合非连续方法3DEC揭示的宏观岩体各向异性特征的途径，完成由连续方法间接描述非连续节理岩体各向异性力学行为的等效过程。研究表明，在无法应用解析法估算含随机断续节理岩体宏观参数时，数值试验成为了更有效的途径。采用遍布节理模型描述断续节理岩体各向异性强度特征时，节理强度参数值受断续节理与岩桥的综合影响，等效节理参数高于节理真实参数。此外，在进行等效连续过程中，为保证等效贯通节理导致的岩体强度凹陷与断续节理作用的方向一致，遍布节理模型中节理走向取值应与断续节理走向呈( － )/2夹角。

STUDY OF EQUIVALENT STRENGTH PARAMETERS OF UBIQUITOUS JOINT MODEL FOR ENGINEERING ROCK MASS WITH PREFERRED INTERMITTENT JOINTS

Preferred discontinuity derived from diagenesis and tectonics reworking always results in the anisotropic characteristics of engineering rock mass. Large-scale engineering rock masses with intermittent joints set have anisotropic strength characteristic，which is influenced by the rock bridge either. So the test results of intermittent joints can not be directly used for ubiquitous joint model，while the equivalent continuum persistent joint parameters should be adopted. When the macroscopic anisotropy simulated by FLAC3D ubiquitous joint model coincides by 3DEC model，the equivalent continuum persistent joint parameters can be defined by inversion analysis. Then，indirectly equivalent continuum method has equal function with discontinuum method in describing anisotropic mechanical behavior of rock mass. In summary，numerical experiment has become a more effective way than analytical method to estimate the macroscopic parameters with random intermittent jointed rock mass. Result shows that the equivalent strength of the equivalent continuum persistent joint parameters by the combined effects of intermittent joints and the rock bridge is higher than that of the real intermittent joints. In addition，in order to keep the definition of the set of directions where the strength of the equivalent discontinuities is equal to the strength of the intermittent discontinuities containing rock bridges，the most likely apparent dip direction of the ubiquitous joint model should have ( )/2 separation angle with the real dip direction of the intermittent joints.