Study On Anisotropic Mechanical Model And Parameters Of Anchored Rock Mass

As an important reinforcement method,geotechnical anchoring technology has been widely used in slope engineering and underground engineering,but the calculation theory and evaluation method of anchoring support effect lags behind engineering practice.On the basis of previous studies,the anchored rock mass is regarded as a supporting whole for quantitative analysis and research.The anchor bolt support has directionality,its mechanical properties should be considered from two directions:the main direction is the anchor bolt reinforcement direction（axial）,the other is two mutually perpendicular directions（radial）of the plane perpendicular to the main direction.The mechanical concept model which is unidirectional reinforced anisotropy of rock mass with anchor is introduced to establish the micro-mechanical equivalent model of composite material of anchored rock mass support system,Taking the mechanical test of anchored rock mass as a research method,the macroscopic properties and mechanical response of anchored rock composites is quantitatively evaluated.Based on the FLAC³DD platform,the constitutive model of the equivalent mechanical model of the anchored rock mass is developed,and the developed model is applied to the actual engineering.The specific research process is as follows:（1）The anchored rock mass is regarded as a fiber reinforced composite material via using the research methods and viewpoints of composite mechanics.By using the analysis and hypothesis of the Mori-Tanaka method,the mechanical expressions,which is the elastic parameters in the elastic matrix of the anchored rock mass,are derived on the basis of the mechanical concept model of unidirectional anisotropy enhancement of anchored rock mass and the Eshebly equivalent inclusion theory in the micromechanics of composite materials.（2）The rock similar materials are obtained on the basis of the orthogonal experimental design method.Through the indoor anchor rock mass model test,the elastic mechanical parameters of the anchored rock mass under different anchoring methods and anchoring density are studied,which can verify the feasibility and adaptability of the ideal model of rock mass reinforcement composites.（3）The interaction between the anchor and the rock mass is simulated by the cable unit that comes with the FLAC^3D.Considering the"contribution"of the anchor to the stiffness and strength of the original rock mass,the anchoring unit has different material parameters in the axial and radial directions of the anchor,the unit through which the anchor passes is treated as a layered anisotropy.On the FLAC³DD platform,based on the theory of transversely isotropic elasticity,as the stress increases,the tensile stress criterion and the Mohr-Coulomb criterion are used to judge the tensile and plastic yielding of the anchored rock mass,and the stress is corrected for the yielding unit in accordance with the plastic flow law.On this basis,the constitutive model development of anchored rock mass is carried out.（4）The developed anchor rock mass model is applied to the numerical simulation calculation of high slope anchor support design,which further verifies the rationality of the model.Finally,the research results of this paper are summarized,and the future research directions are further prospected.The research of anchor support mechanism will contribute to the wide application of anchoring engineering design and anchor technology.