Inverse analysis of micro-mechanical parameters of rock-forming minerals based on nano-indentation technology

The micro-mechanical properties of rock-forming minerals have an important influence on the macro-mechanical properties of rocks. However, it was difficult to obtain the micro-mechanical parameters of rock-forming minerals directly through traditional experiments. In this paper, an inverse method of micro-mechanical parameters of rock-forming minerals based on nano-indentation technology was proposed. In the forward analysis, the nano-indentation test was performed on four typical granite minerals. In the reverse analysis, an axisymmetric finite element model was used to simulate the nano-indentation test on granite minerals. Then, the calibration procedure of micro-mechanical parameters based on central composite design was established to reproduce the nano-indentation curves of four typical granite minerals. In order to verify the validity of inversion results, the optimized micro-mechanical parameters were inputted into the finite element model to gain the numerical curves, and they were compared with the curves of nano-indentation test, the simulated curves match well with the test results. Furthermore, the uniaxial compression model of rock based on mineral were established to further verify the accuracy of inversion results, the simulation results show that the inversion results can better simulate the macro-mechanical properties of rock. This study develops an inverse method of rock-forming minerals based on nano-indentation test, and it may be helpful to explain the macro-mechanical properties of rock from the micro-mechanical perspective and to establish the micro-mechanical model of rock.