Study on relationship between principal stress difference of surrounding rock and distribution of plastic zone under three-dimensional non-isobaric stress field
Firstly,based on the elastic theory,the analytical formula of principal stress difference considering the influence of axial stress in roadway was derived.Under complete elastic condition,the evolution law of principal stress difference distribution at different stress fields was studied by changing horizontal lateral pressure ratio and axial lateral pressure ratio.Secondly,the approximate solution of plastic zone of surrounding rock considering axial stress was derived,and the evolution law of plastic zone morphology of surrounding rock under different stress environments was studied.Finally,the principal stress difference and the morphological characteristics of the plastic zone were compared and analyzed,and the corresponding relationship between the two distribution patterns was studied.The correctness of the theoretical analysis was verified by numerical simulation.The results show that under the elastic theory,the distribution of the principal stress difference under the three dimensional stress field conditions will show three forms of the evolution law,i.e.,circle,ellipse and butterfly.Considering the plastic failure of the roadway,the principal stress difference forms a peak shell on the smaller side of σx and σz,and a pressure relief shell on the larger side.Under different horizontal and axial lateral pressures ratios,the plastic zone morphology of surrounding rock will show three stages of evolution,i.e.,circular to elliptical,elliptic to butterfly and butterfly malignant expansion.The distribution of the principal stress difference of the roadway can reflect the shape of the plastic zone to a certain extent.The morphological characteristics of the principal stress difference and the plastic zone under the same stress conditions have a corresponding relationship,and the shape of the two is largely determined by the horizontal lateral pressure,while the axial lateral pressure ratio has little effect on the shape of the plastic zone.The 160206 return airway forms asymmetric alienation characteristics in the concentrated area of deflected principal stress difference.The field application effect of the proposed joint support technology based on the analysis and field damage is good.
difference between principal stressesaxial stressroadway plastic zonenon-hydrostatic pressure fieldsurrounding rock control
万方数据
维普
