Constitutive Model of Columnar Jointed Rock Mass Based on Cosserat Theory

The complex anisotropy of columnar jointed rock mass poses a challenge to the smooth development of related engineering. It is very important to accurately grasp its anisotropic mechanical parameters to reduce engineering risks. Based on Cosserat theory and Goodman’s equivalent superposition principle, the two-dimensional constitutive model of four-prism, five-prism and six-prism columnar jointed rock mass is firstly established, and the constitutive relation is extended to the three-dimensional space by introducing the stress concentration coefficient. Aiming at the column jointed rock mass of Baihetan hydropower station, the value of engineering constant is calculated by three models, and the difference between the calculation results of three models and the value of engineering experience is analyzed, and the anisotropy characteristics of three models are compared. The results show that the calculated values of the three models are close to those of the empirical formula and the in-situ test results of the bearing plate, and the elastic parameter variation curves of the column-jointed rock mass models of four-prism, five-prism and six-prism respectively reflect the anisotropy, quasi transverse isotropy and transverse isotropy of each model.