| Most surrounding rocks in coal roadway belong to layered or massive structure with low intensity, joint fissures, and poor integrity; influenced by many project environmental factors simultaneously, it becomes a difficult problem more and more that how to control and support the surrounding rock for production and safety in coal mine. Tracing its reasons, the main problems include:①it lacks accurate mastering and scientific appraisement about geological mechanical properties and project environmental condition;②there is no clear recognition to the deformation destabilizing mechanism of roadway surrounding rock;③there is no enough stability control and anchorage theory aimed at the mechanical properties of roadway surrounding rock;④accurate and scientific appraisement on the stability of roadway surrounding rock cannot be made;⑤the surrounding rock stability appraisement cannot be combined with support design closely and cannot guide the surrounding rock control and support. There is no scientific quantitative judgment technique direct to the stability of roadway surrounding rock under special conditions; it lacks scientific theory system for appraising on the stability of different roadway surrounding rocks, which all influence the stability control and support effect of roadway surrounding rock. Therefore, it is a technique subject pressing for solution to further discuss on stability control and anchorage theory of roadway surrounding rocks, systematically study the influence of geological mechanical properties of surrounding rock in large section roadway and project environmental condition utilizing strata control science and geological mechanical theory, accurately master the structure of surrounding rock and its influence on surrounding rock stability, and taking support design as the central explore a surrounding rock stability appraisement system which is suitable for large section roadway.The surrounding rock stability control and appraisement in coal roadway aims to reflect the complexity of surrounding rock structure scientifically and accurately and to provide a reliable basis for the roadway surrounding rock control and support design. Summarized all kinds of appraisement methods at home and aboard, we can see that those methods had insufficient integrity, the emphasis points, the selected indicators and grading methods were diffident. At present the studies on surrounding rock stability control and appraisement in coal roadway at home and aboard mainly have the following characteristics:(1) The study on geological mechanical properties and project environmental condition of surrounding rock in coal roadway is not very comprehensive and accurate. There is no clear recognition to deformation destabilizing mechanism of roadway surrounding rock. There is no enough stability control and anchorage theory aimed at the mechanical properties of roadway surrounding rock.(2) The classification of surrounding rock stability is developing from the mode of single factor and qualitative graduation to the dynamic mode of multi-factors and quantitative graduation. However, the factors influencing surrounding rock quality have obvious characteristics of uncertainty, complexity and fuzziness. It is difficult to generalize the practical situations accurately and comprehensively by minority fixed appraisement indicators and simple mathematical expressions, and the complete quantitative graduation of surrounding rock quality only has mathematical significance.(3) All kinds of surrounding rock quality appraisement methods select several fixed participating factors from different sides, and carry on simple linear operation according to certain standards, then obtain single scores of surrounding rock quality, and then based on these scores make classification about the stability of surrounding rock. Although these methods are simple and convenient, they cannot reflect the complicated and diversified geological situation, but only reflect one aspect characteristic of surrounding rock stability. The factors influencing the surrounding rock stability usually have complex characteristics of multi-levels, fuzziness, uncertainty, etc. Regarding the different geological backgrounds and the concrete project, their influencing factors and weights are not fixed, which both have the intercommunity and the particularity.(4) The classification of rock stability is founded on analysis mainly on the intercommunity of geological condition in mining areas. However, in same mining area even in same roadway, the rock condition has great difference and each forms partial particularity as result of the different influence of geologic structure and neighboring project environment. The rock stability is different in same mining roadway, so we should consider the influence of geologic structure and project environment completely while carrying on appraisement.Therefore, the stability appraisement of roadway surrounding rock should adopt both static and dynamic appraisement methods to dynamically appraise from different sides. In same mining area we should consider the influence of geologic structure and project environment where the individual roadway locates while carrying on appraisement.Based on the above viewpoints, taken large section coal roadway of Shanxi Yamei Daning energy Limited company and geological structure as the study objects, this paper has adopted theoretical analysis, field measurement, numerical simulation calculation, industrial experiment and other methods to make an exploratory research on the surrounding rock stability control theory in coal roadway, geological mechanical appraisement and support design, the influencing weight and revision of the disturbance factors, numerical simulation and verified optimization, and formed the surrounding rock stability control and dynamic appraisement system. The main research achievements as follows:(1) Based on geological mechanical properties in coal roadway surrounding rock, the paper has studied the characteristic of stress distribution and the mechanism that support influence roadway surrounding rock stability, and discussed on the rule of deformation and destruction of coal roadway surrounding rock.(2) The research has analyzed the stability condition of coal roadway surrounding rock utilizing elastic-plastic theory, exposed the destabilization and destruction mechanism of surrounding rock, and also according to coal seam's mechanical properties of cracked body and coal body studied how to design the anchorage wall's thickness, bolts'geometric and mechanical parameters of the broken sides using thick plate theory.(3) The paper has researched the principle of control and anchorage under the different equilibrium states of surrounding rock stability; and suggested adopting the principle of state control for surrounding rock with good stable condition, the principle of deformation control for surrounding rock with bad stable condition, and the principle of whole anchorage structure for surrounding rock with low intensity and hydrostatic pressure state.(4) Taken stability control of roadway surrounding rock and support design as the central, utilizing strata control science and geological mechanical theory, the paper has formed a trinity dynamic appraisement system of roadway surrounding rock stability based on geological mechanical appraisement and support design, the influencing weight and revision of the disturbance factors, numerical simulation and verified optimization.(5) Through taking the core on spot and testing it in the laboratory, the paper has made experimental analysis on each layer's geological mechanical properties in 15m scope. Also it has made preliminary appraisal on surrounding rock stability and design of support scheme, and constructed the appraisement method based on the trinity of geological mechanical properties of surrounding rock, stability appraisement and support design.(6) The paper has confirmed the importance that the exterior disturbance factors (geological structure, neighboring project) had influence on surrounding rock stability; In view of the characteristic of project environment where the coal roadway locates, the paper has analyzed the influencing scope and graduation of each exterior disturbance factor including geologic structure, neighboring project environment and mining pressure to the stability of roadway surrounding rock, fixed the weight of disturbance factors, appraised the influence and revised the supporting scheme of surrounding rock stability, and formed a unique appraisement system based on the disturbance factor weight.(7) Utilizing numerical simulation analysis, the paper has researched the stress and deformation distribution rule and the characteristic of abscission layer under supporting and non-supporting roadway surrounding rock. And through the analysis on the stability state of surrounding rock, the paper identified and optimized the supporting scheme.In a word, this paper constructed the surrounding rock stability control and dynamic appraisement system of large section roadway through systematic research, which has solved the actual problems existing in the surrounding rock stability control and support of large section roadway and provided a scientific basis for the future control and support of surrounding rock in coal roadway. |
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