The Key Influencing Factors And Model Research Of Three-Dimensional Mining Stress Measurement

The accurate measurement of mining stress is of great significance to underground engineering such as excavation of roadway.At present,the drilling stress relief method can be used to measure the original rock stress with high measurement precision,and it is very important to apply it to mining stress measurement considering the advantages of stress measurement of borehole stress.But mining stress is different from the original rock stress measurement,because of the theory of ideal model has great error when applied to mining stress measurement,and mining plastic damage of rock mass,uneven distribution of stress around borehole stress are also the important factors of measurement accuracy.This paper take the method that combines the simulation test of the theoretical model based on the finite element stress relief method and the simulation analysis of roadway excavation to carry out the correlation analysis on the real change distribution law of mining stress,the actual results of stress tensor inversion under the influence of mining,the error influencing factors and the correction coefficient of the reverse calculation measurement of the mining stress model.The research results are as follows:?1?Numerical simulation analysis of roadway tunneling 3d numerical model was established by using the finite element numerical analysis program ANSYS,and the distribution evolution law of three dimensional stress tensor with the excavation process of the roof,bottom plate and the surrounding rock in the roadway excavation is obtained,at the same time main stress evolution path of three deep perturbations?the distribution law of the supporting pressure is in good agreement with the measured data,which verifies the correctness of the model?.?2?In this paper,the stress relief method is used to measure the stress of the original rock and the mining stress..Based on the analysis of different pore size models,the influence law of the calculation error size of the stress measurement with the specific change law of roadway tunneling and the influence law of the hole diameter corresponding to the error size is studied.?3?Based on the principle of stress relief,a model for the calculation of mining stress is established,and Combined with finite element method to solve the three-dimensional In-situ stress,the concrete effect of the inverse calculation error of stress measurement with the model of elastic ring size?R2/R1?,the surrounding rock elastic modulus ratio?E2/E1?,and thepoisson's ratio?m₂/m₁?of surrounding rock and the plastic ring size?R3/R2?are systematically researched.The specific influence law is described quantitatively.?4?Based on the finite element numerical simulation,the calculation and correction of the reverse calculation model based on the stress relief method is carried out,and the model mining stress path loading verification is carried out.The accuracy of the method is improved,and the error is reduced obtaining the strain correction term [?-M^j] and the correction measurement inverse coefficient [C_ji].