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岩土工程中经常遇到受多组密集定向节理面切割的破碎岩体,对该类岩体的力学行为展开研究则需建立合理的本构模型。针对含有不超过三组节理弱面斜交切割的节理岩体,将其考虑为一种广义宏观复合材料,建立了复合型多弱面软化模型。设定不同的屈服因子可使岩体材料满足Mohr-Coulomb和受拉破坏的复合屈服准则或Hoek-Brown强度屈服准则。节理面服从Mohr-Coulomb和受拉破坏的复合屈服准则,并且具有双线性特性。软化参数描述为与塑性应变和拉应变相关的变量,通过软化参数可描述节理岩体各种软化特性曲线。基于FLAC3D本构模型的二次开发平台,成功实现并嵌入该复合型软化模型,并通过双节理面斜交岩体的单轴压缩试验进行验证,计算结果与试验比较吻合,符合岩石的宏观破坏机理,表明了该模型的正确性。
In the geotechnical engineering, the fractured rock masses which are often cut by many groups of densely oriented joints are often encountered. To study the mechanical behavior of such rock mass, a reasonable constitutive model must be established. For the jointed rock mass containing not more than three groups of oblique slant intersecting facets, this model is considered as a generalized macroscopic composite material, and a composite softening model of weakness is established. Setting different yield factors can make the rock mass meet the composite yielding criterion or Hoek-Brown yielding criterion of Mohr-Coulomb and tensile failure. The joints obey the composite yield criterion of Mohr-Coulomb and tensile failure, and have bilinear properties. The softening parameters are described as variables related to plastic strain and tensile strain. Various softening characteristics curves of jointed rock mass can be described by softening parameters. Based on the secondary development platform of FLAC3D constitutive model, the composite softening model is successfully implemented and embedded, and verified by the uniaxial compression test of bi-jointed rock slab rock mass. The calculation results are in good agreement with the experimental results and accord with the macroscopic failure of rock Mechanism, shows the correctness of the model.