Research On Collapse Mechanism And Surrounding Rock Control Of Large-span Roadway In Deep

In recent years,with the rapid development of coal industry and miningtechnology, coal mining depth is increasing, geological condition is more complexand the roadway section is bigger. However, the present theories and technologies areunable to satisfy the requirements on the support of large-section and long-spanroadways which are in deep, and the collapse of long-span roadways has occurredfrequently. Therefore, it is urgent to solve the problems referred above. A syntheticallymethod combined with numerical simulation, similar simulation, theoretical analysisand field observation is applied to study the collapse mechanism of long-spanroadways in deep and surrounding rock control technology systematically, and theinnovative achievements are shown as follows:(1) Based on the theory of complex variable function, the expressions ofsurrounding rock stress and displacement in long-span rectangular roadway arededuced using Schwartz-Christophil method which solves mapping function. Byintroducing specific example, the numerical solutions on stress and displacement ofeach point in rectangular roadway are obtained, and the laws of stress anddeformation of surrounding rock in rectangular roadway are analyzed.(2) With the application of FLAC3D software, the plastic region distributionlaws of rectangle roadway in different pressures and spans are studied systematically,and the plastic region distribution shape changing laws with side pressures areobtained. The definition of large-span roadway is given and the type of large-spanroadway is divided according to the damage, stress distribution and deformation ofsurrounding rock in roadway with different side pressures and spans. Meanwhile, thedefinition and structural form of double micro arch section roadway are given.(3) A miniature experimental apparatus of prestressed anchor is developedwhich provides convenience for prestress infliction and stress monitoring of anchor insimilar simulation experiment, it solves the problem of prestress infliction of anchorin similar simulation experiment.(4) The concept of double micro arches is proposed and a calculation model isestablished based on the complex function theory and elastic theory for double microarch roadway. The expression of stress and displacement of double micro archroadway is worked out. The stress and changing laws of surrounding rock in doublemicro arch section roadway is analyzed. The computation model of counter-force at interaction of arch feet in double flat arched section roadway is established and itscomputation formulas are deduced.(5) For the main influencing factors in long-span roadway, the controllingprinciples of long-span roadway are analyzed. The supporting principle of "reasonablesection shape+three high and one low+method of effective reducing span" is putforward.(6) According to the supporting theory and methods of deep and long-spanroadway, the7801cut eye of Wuyang mine in Shanxi Luan Huanneng StockCompany, of which the depth is800m and the span is8m, is done some industrialnessexperiments. The site applications show that adopt "reasonable section shape+threehigh and one low+method of effective reducing span" can effectively control thedeformation and destroy of cut eye and make the stale control of surrounding rock indeep and long-span cut eye come true.