Study On Mechanism Of Rock Roadway Floor Heave Of High Ground Stress With Continuous Double Shell Support

With the continuous development of the deep coal resources and the building of the deep mines, the occurrence of the high ground stress problems becomesthe dominating factor endangering the roadway rocks stability.The roadway supporting theory and technology for the shallow mining can hardly adapt the problems on the roadway rocks stability and supporting in the state of the high ground stress, and the roadway floor heave becomes one of the main forms of roadway rocks deformation and failure, which makes a new research topic on the governance of rock roadway floor heave with the state of the high ground stress beput forward. Therefore, it is particularly important and urgent to study such problems as the mechanism and the reinforcement technique of the roadway floor heave with the state of the high ground stress. From this starting-point and combined with the National Natural Science Foundation Item “Study on the supportingmechanism of reinforcement of deep roadway "double shell" grouting”(51174070) and the entrusted project “Study on the technology and mechanism of floor heave control with double shell of permanent roadway and chamber in the state of the high ground stress” from Shanxi Xinjing Mine, based on mining science, rock mass mechanics, elastic-plastic mechanics and fracture mechanics, the mechanism and the characteristics of the roadway floor heave in the state of the highground stress in the coal mines was studied with the similar material simulation,theory analysis, numerical simulation, site observation and engineering practice, then the support technique and method of the of the roadway floor heave in thestate of the high ground stress is put forward. The major contents in this paperare as follows:The three different mechanisms of the roadway floor heave in the state of the conventional ground stress are described and analyzed. The influences of thehigh ground stress and the horizontal stress to the roadway floor heave are analyzed by comparison of the characteristics of the roadway floor heave in the stateof the high ground stress. The new theory of the roadway floor support,which is not only strengthening of the shallow floor rock to reduce the influence to theroadway floor rocks of the damage of the shallow floor rock and the second horizontal stress, but slaso prevent the stress spreading from the deep rocks of theroadway floor to the shallow floor rocks is summarized. The conception and mechanisms of the double shell support of the roadway is put forward. The support way of the continuous double shell, which shuod include both the grouting reinforcement and the anchor beam support, is obtained.The similar material simulation of the support technique and method of theof the roadway floor heave in the state of the high ground stress is designed. The objective, principle, process and the treatment method of the experimental results etc are described. The new type CM250/18test-bed which is designed andmade by myself and the proportion experiment of mixture of Similar materials are Introducted. The boundary conditions and test system of the similar material simulation are designed. Then, the numerical simulation is designed, and the method of cross conparionn analysis of the the experimental results is determined.Base on the side pressure coefficient is1.0and1.2of the similar materialsimulation, the feasibility and superiority of the support of the continuous doubleshell is explained with comparative analysising the stress and displacement of the roadway surrounding rocks with supporting by original supporting and the support of the continuous double shell. Then, analysis and explain the new featuresof the roadway surrounding rocks in the state of the high ground stress by analysising the stress change of the roadway surrounding rocks with no supporting.On the condition of fice different roadway supports and four different sidepressure coefficients (λ=0.8、1.0、1.2、1.5), the data and screenshot of the vertical displacement, horizontal displacement, vertical stress, horizontal stress and plastic zone of the roadway surrounding rocks are cross conparionn analysised. Then, the influence of the different side pressure coefficients to the roadway floor heave and the supporting effect of different roadway supports to the roadway floor heave are researched. Finally, the results is basically identical with the resultsof the similar material simulation.For the existing problems on the supports of the roadway floor heave underthe condition of high ground stress, based on the result of the theoretical analysis and the practice, the supporting project is designed with pertinence and the in situ engineering tests are carried out. It can be shown from the measured datathat the supporting project used controls the final amount of the roadway floorheave and improves the safety and economy of the roadway, which verifies the feasibility of the project.