Study On Structural Effect Of Surrounding Rock And Catastrophic Evolution Mechanism Based On Multi-source Information Fusion

The stability of deep surrounding rock is not only related to the strength of rock mass,but also to the structure of rock mass,which leads to structural instability in severe.Therefore,it is of great significance to study the structural effect of surrounding rock and its catastrophe evolution mechanism for the effective control of the deformation and instability in the complex structure of the surrounding rock.For this purpose,the destructive physical model tests of surrounding rock with intact,layered and blocky structures were carried out in this thesis by using the self-developed large-scale physical model test system,and in coordination with acoustic emission,parallel electrical method and electromagnetic radiation monitoring systems.Based on the evolution law of multi-source monitoring information,the whole loaddisplacement process of surrounding rocks with different structures was quantitatively analyzed and characterized by information,and furthermore the post-peak damage and re-bearing characteristics of surrounding rock were explored.The catastrophic evolution and instability mechanism of surrounding rocks with different structures were comprehensively revealed from multi-source information response law,deformation failure mechanism,and post-peak rebearing characteristic.The research was funded by the Key Program of National Natural Science Foundation of China(51734009)and General Program(52074259),the main achievements were as follows:(1)In the study on the structural effect of surrounding rock in deep roadway,the destructive physical model tests for the whole process of deformation and instability of surrounding rock with intact,layered and blocky structures were carried out.In the roadway excavation stage,the layered structural plane increases the sensitivity of surrounding rock stress to the excavation disturbance,and the pressure arch continuously shifts to the distance.Compared with the intact surrounding rock,the inner boundary of the pressure arch of the layered and blocky surrounding rock expands 65.4% and 107.8%,respectively.In the process of load loading,the surrounding rock with intact structure presents an overall progressive continuous deformation,while the surrounding rock with layered and blocky structure presents a periodical jumping rule.The structural effect of surrounding rock failure and instability is more and more significant,and the mechanism of failure and instability is transformed from the strength control type of intact structure to the structure control type of blocky structure,while the layered structure shows the characteristics of strength and structure joint control.(2)In terms of information characterization of the disaster evolution of surrounding rocks with different structures,the acoustic,electrical and magnetic multi-source information of the whole load-displacement process of surrounding rocks with different structures was collected synchronously.Based on the response of multi-source information,the failure evolution mechanism of surrounding rocks with different structures was comprehensively characterized.Different from the continuous response of intact surrounding rock,the layered and blocky surrounding rocks show phased responses and their characteristic values are more prominent.Combined with the whole load-displacement curve,the deformation bearing characteristics of surrounding rock of different structures were quantitatively analyzed.Compared with the intact structure,the equivalent peak bearing capacity of surrounding rock with layered and blocky structures is reduced by 4.73% and 20.65%,respectively.Based on the fusion of multi-source information,the surrounding rock instability warning model was established,which gives full play to the advantages of acoustic electromagnetic information response,and greatly improves the possibility of effective prediction of surrounding rock structural deformation instability.(3)In the research of the post-peak reloading characteristics of surrounding rocks with different structures,the laws of post-peak damage degradation of surrounding rocks with different structures were quantitatively evaluated from multiple angles by using ultrasonic wave velocity tester,borehole peepometer and indoor rock mechanics test system.Based on ultrasonic wave velocity,the post-peak damage distribution characteristics of different structures were analyzed quantitatively.By means of borehole imaging method,the development characteristics of fractures in surrounding rock of different structures were visualized.Based on the peak strength,three-dimensional fractal damage and equivalent fracture degree of surrounding rock samples,the post-peak reloading characteristics of surrounding rock with different structures were comprehensively discussed.(4)In terms of stability control of surrounding rock of different structures,the numerical simulation test of surrounding rock with different structures under the form of reinforced support was carried out by using the discrete element method.From the dynamic evolution of meso fracture field,displacement field and stress field and the instability form of surrounding rock,the effectiveness of three support forms,namely,ordinary anchor cable,high preload anchor cable and anchor cable + steel belt,was discussed.The support concept of improving the shear resistance of surrounding rock with layered structure and strengthening the integrity of surrounding rock with massive structure was put forward.It provides guidance for the selection of targeted surrounding rock stability control measures according to the deformation and instability characteristics of surrounding rock with different structures.