| In mine construction and production process,working face roadways or opening,because of excavation or extraction disturbance,will change the region near the original rock stress,and then lead to high stress concentration in a particular area,easy to cause deformation and instability of surrounding rock of roadway,serious and even lead to narrow roadway section,for this kind of phenomenon is extremely obvious in soft rock,easily lead to coal mine production transportation is blocked,or poorly ventilated,roadway is destroyed,and when the cost of the roadway maintenance cost,the most important thing is that may lead to the stagnation of production,reduce the mine production efficiency.Soft rock problem although made a certain progress in the prophase,but because of the complexity of mining rock mass mechanics,the mine of soft rock roadways support problem is still serious,the deformation mechanism of roadway surrounding rock will remain to be further defined later scholars,more economical and durable supporting method and materials in the field is still in short supply,because the nature of soft rock is relatively complex,engineering boundary to be determined more difficult to find a common supporting method is suitable for all kinds of situation,must be based on the corresponding supporting structure is found at the scene have corresponding supporting solution.Up-hill mountain coal mine,the author of this thesis 2 straight ROM group under section 11 mining area coal aquifer soft rock roof support study,combining with the actual situation,based on the existing research results,combining field observation and numerical simulation,downhole and laboratory experimental methods of engineering practice,soft rock roof support of aquifer has carried on the systematic analysis and research,through the author's own up-hill mountain coal mine with the scientific research unit jointly research and test,which can be used for reference in the field of the supporting scheme is obtained,and many meaningful results:Through the underground field test,the strength parameters of No.2 coal and roof mudstone of Maidushan Coal Mine,as well as the characteristics of floor mudstone,such as expansibility and water weakening,reveal the stress characteristics of roadway deformation and failure.According to the anchoring force test and torque conversion result analysis of underground anchor bolt in the laboratory,water has a great influence on the anchoring force of surrounding rock,and the pretightening torque conversion efficiency of soft rock roadway is low.Therefore,water pouring should be blocked as much as possible to ensure the anchoring force of surrounding rock and improve the initial pretightening force.Based on the analysis and summary of the existing problems in the original support of Maidushan Coal Mine,the concept that should be followed in the support of No.2 coal soft rock roadway in Maidushan Coal Mine is put forward,that is,the concept of "large surface area,high conversion efficiency,advance grouting water plugging and reinforcement,high prestressed anchorage in full length".According to this idea,the supporting scheme design of the test roadway is put forward.According to the underground field implementation,the supporting effect of roadway has been significantly improved through the adoption of the supporting concept of equal-height prestressed anchor bolt by increasing the protective surface area,increasing the preloading force of anchor bolt and the use of grouting anchor cable.The roadway deformation is about 80% lower than the original.There are 81 figures,14 tables and 93 references in this thesis. |
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