Study On Energy Evolution Characteristics And Movement Law Of Overburden Based On Mining Influence

The coal resources are mostly in sedimentary strata,and the coal seam and its upper overburden are usually composed of different lithologic layers or interlayers.In the process of tunneling,it is easy to lead to the fracture and destruction of the goaf roof,which induces the multi-direction mis-movement and sliding of the upper overburden,leading to the failure of the control of the roof of the coal seam,and finally the overall instability of the upper overburden of the coal seam.Roof rock failure is the direct cause of inducing and accelerating the collapse failure of overburden rock.Therefore,it is urgent to study the evolution characteristics of mechanical behavior of roof rock failure.The energy theory is used to reveal the mechanical damage mechanism of rock,and the internal conditions of driving and accelerating the deformation and failure of roof rock are analyzed.Then by similar physical model test,to master the upper coal seam deformation of overburden rock caving rule,be based on the influence of mining coal seam and roof strata overall instability mechanism,research results will have higher scientific significance and wide engineering application background,the prevention for disasters in direct control of roof bolting design,and production safety is of important engineering value.Based on roof rock as the research object,research mainly by means of indoor physical mechanics test,get basic rock physical and mechanical and chemical parameters,determine compression damage evolution characteristics,rock damage theory,combined with energy building energy of rock damage model,and through indoor physical analog simulation test strata movement rule,mainly made the following findings:(1)The mechanical properties of roof rock samples were tested to obtain the stress-strain curve of rock.The sensitivity of rock deformation and failure to the characteristic value of energy was analyzed in combination with the energy theory and elastic damage mechanics of rock.The rock energy damage model was derived and constructed by determining the critical sectional damage variable of the model and calculating the characteristic value of the internal energy of rock in stages.It is in good agreement with the experimental results and has a certain scientific nature.(2)Based on the rock mechanical parameters obtained from the laboratory test and the data provided by the mine,the physical similarity simulation test was carried out to simulate the migration and collapse law of the roof and overlying strata under the influence of mining,and the stress and displacement deformation in the mining process were monitored.According to the test results,the initial rupture distance of the basic roof was 30 m,and the periodic rupture distance was 10 m.In line with the limit span requirement of rock beam theory,the fracture Angle before mining is about 60,and the fracture Angle after mining is about 55.(3)Based on the rock energy damage model,FLAC3 D software is used for numerical simulation to analyze the deformation and failure law of coal seam roof and overlying strata in the mining process,and the simulation results are compared with similar test results.It is found that the two have a high degree of coincidence at the roof,and the maximum error is only0.043 m when the mining height is 4m.However,it decreases with the increase of distance from coal seam,but both conform to the overburden migration law of shallow buried near horizontal thick coal seam mining.In conclusion,the damage and deformation law of roof rock mechanical properties is revealed from the principle,which provides theoretical and application basis for enriching and expanding the energy theory to analyze the rock damage law,and provides scientific basis for the stability of coal seam roof and overburden under the influence of mining.This paper has 35 figures,7 tables and 72 references.