| During mine into Km mining stage,coal mine attained more and more concentrations on grasping bearing characteristics and instability mechanism of the surrounding rock mechanical bearing structure,and designing reasonable surrounding rock control technology.However,the deep-seated problems such as the divided method of surrounding rock mechanical bearing layer,the its bearing range change rule,the interactive relationship between the mechanical bearing feature of bearing layer and the roadway structural instability mechanism,the factors influenced on bearing layer stability,and the control method of the roadway structural failure were urgently to be solved.The compound bearing layer mechanical characteristic and multi-echelon support control of deep high-stress roadway were studied.By integrating the rock mechanics property test,numerical simulation technology,theoretical research and roadway model test and in-situ test,the divided method and reference standard of"strong-weak-key" bearing layer were proposed,the mechanical model of the coupling bearing layer in deep excavation roadway was established,the formation and evolution law of bearing range of coupling bearing layer were grasped,and the rationality of the coupling support layer was contrastively analyzed.The mechanical bearing characteristics of the "strong-weak-key" coupling bearing layer in the deep roadway were analyzed.The coupling interactive relationship between the stability of coupling bearing layer and the roadway structural failure was analyzed,and the stability influenced factors of the coupling bearing layer were analyzed.The multi-echelon support control method of roadway coupling bearing layer stability was proposed,the bearing layer stability and surrounding rock fracture development law of the multi-echelon support roadway under high horizontal stress were analyzed.Finally the scientific and quantitative multi-echelon support of roadway structural instability was designed.The related works are listed as following:1)Research on mechanical bearing mechanism of "strong-weak-key" coupling bearing layer in deep roadway.Aiming at a kilometer deep roadway,the unstability cross point cavern was selected as researchful object.The mechanical properties test was conducted on different directions rock which was obatained by field coring and indoor secondary sampling with core at fixed angle.The mechanical model divided method of coupling bearing layer was proposed,and the evolution law of bearing range of coupling bearing layer was analyzed,based on the evolution law of the secondary stress field which was tested by the single/double string stress meter during roadway excavation and support.The reasonable judgement of divided method of the coupling bearing layer was analyzed,based on the formation and evolution law of the loose circle and combining with the inner-main bearing layer structural characteristics.The bearing characteristics of coupling bearing layer and its influence on the surrounding rock stability during roadway excavation and support were analyzed by numerical simulated method,and then the mechanical bearing mechanism of the roadway coupling bearing layer was clarified.2)Theoretical research on elastic-plastic mechanics of "strong-weak-key" coupling bearing layer in deep roadway.The coupling equation between the roadway elastic-plastic failure and the coupling bearing layer stability was deduced,with considering the mechanical model of coupling bearing layer.The reasonable constitutive rock model was selected,with considering the mechanical characteristics of surrounding rock.Under engineering background of roadway excavation-supporting,the excavation unloading effect mechanical model and the coupling mechanical model of "surrounding rock-support" were established.Through the analytical example,the coupling interactive mechanism of the coupling bearing layer and the roadway failure are studied.The influenced factors of the coupling bearing layer stability are analyzed,and the structural instability mechanism of the roadway is clarified.Among them,the stability analysis of the coupling support layer,included the secondary peak stress transfer,stress concentrated degree and strength deterioration of the surrounding rock.3)Research on multi-echelon support controlled effect on stability of"strong-weak-key" coupling bearing layer in deep roadway.Corresponding to the theoretical study,the equivalent circle roadway model was established,its multi-echelon support was designed by coupling bearing layer structural characteristics of the naked roadway according to the theoretical study.At the same time,according to the preamble numerical simulation results of bearing structure in the straight wall semi-circular arch naked roadway,its corresponding multi-echelon support was designed.The bearing stability and surrouding rock fracture characteristic under naked roadway,original support and multi-echelon support were simulated by FLAC3D.Finally,the rationality of multi-echelon support method was analyzed.4)Mechanical model test on the multi-echelon support roadway under high horizontal stress.Based on the roadway model experiment,the models of the equivalent circle and straight wall semi-circular archway roadway were designed respectively.The high horizontal stress was conducted by the self-made plane stress simulation test bed.The impacts of high level stress on the stability of the coupling bearing layer and the structural rupture development law of surrounding rock were studied.The multi-echelon support method was designed according to the naked roadway coupling bearing layer structure.Finally,this paper research on the effect of multi-echelon support on limiting the structural fracture development of surrounding rock and instability of coupling bearing layer caused by high horizontal stress.5)Research on field engineering measurement in deep roadway.According to the secondary stress field and the mechanical properties of surrounding rock,the structural characteristics of the roadway coupling bearing layer were grasped,the multi-echelon support scheme and its support parameters were designed quantitatively,the bearing structure stability was analyzed under multi-echelon support.Then,in order to judge rationality the multi-echelon support,the deep-shallow displacement observation and deep hole drilling peep were used;the bearing layer stability of roadway,surrounding rock loose circle distribution,and its elastic-plastic deformation were analyzed,under the original support and multi-echelon support. |
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