Stability Analysis And Three-dimensional Reconstruction Of Surrounding Rock Based On Failure Approach Index

In recent years,with the vigorous development of the development and utilization of underground space in China,more and more projects such as urban subway,highway and railway tunnels,mining engineering were set up.During the construction of these projects,there will often be collapse accidents caused by the instability of surrounding rock after tunnel excavation.Therefore,how to evaluate the stability of surrounding rock and how to visualize the distribution and development law of the internal failure form of surrounding rock are of great significance.Based on the National Natural Science Foundation of China(No.51874112),“ Research on the Evolution of Mechanical Behavior and Dynamic 3D Dynamic Fracture Morphology of Mining Rock Masses ”,this paper deduced the failure approach index of quantitative evaluation of surrounding rock stability based on the mohr-coulomb yielding criteria,and developed a three-dimensional reconstruction function for the evolution of internal crack morphology of rock based on FLAC3 D and MATLAB software.Finally,the above two results were presented in the examples.The main research findings and conclusions completed in this paper are as follows:(1)Based on the failure criterion of rock,the safety factor function and the failure approach index function were derived,which can evaluate the stability of surrounding rock.And the failure proximity function was selected through the comparative analysis of numerical simulation.At the same time,according to FAI,the stability of surrounding rock was divided into four zones to quantitatively describe the stability of surrounding rock,which provided a basis for determining the excavation disturbance area and dangerous area in the process of Engineering construction.(2)Because of the heterogeneity of rocks and the mechanical parameters of the model are mostly homogeneous in the conventional numerical simulation,the mechanical parameters of the numerical model were randomly assigned by FISH programming language,which can make the numerical simulation results more accurate.Finally,the comparative analysis showed that the method can better simulate the heterogeneity of rocks.(3)Through the software such as FLAC3 D and MATLAB,the visual representation of the three-dimensional morphological evolution of the internal crack damage zone of rock was realized.Then,taking the numerical simulation test of uniaxial compression as an example,the feasibility of this method was verified by displaying the three-dimensional morphological evolution effect diagram of crack in the model and compared it with the typical indooruniaxial compression test pattern.(4)The numerical simulation method was used to reproduce the progressive failure process of surrounding rock during tunnel excavation,and based on the failure approach index function,the three-dimensional reconstruction of the surrounding rock failure area was reconstructed.Finally,the feasibility and practicability of the stability evaluation of surrounding rock by the failure proximity were verified by comparing with the actual failure form on site.