【作者】 杨培举；

【导师】 刘长友；

【作者基本信息】 中国矿业大学 ， 采矿工程， 2009， 博士

【摘要】 随着综放技术的成熟与推广应用,综放工作面开始向着自动化、信息化的方向发展。两柱掩护式放顶煤支架正是依据这一发展要求而研创的液压支架新架型。该架型在实践中表现出了高效的支撑能力与良好的控顶效果,进一步提升了我国综采放顶煤技术水平。论文采用物理模拟方法研究了两柱掩护式放顶煤支架与围岩的动态作用规律,分析了顶煤硬度、支架主要结构与支护参数对支架与围岩作用过程的影响。研究表明,在综放工作面,顶煤具有“双区失稳”运动特征,其动态发展过程影响了两柱掩护式放顶煤支架与围岩关系的稳定性,成为影响支架顶板控制效果的关键因素。提高支架工作阻力,减小顶梁前后比值可以提高支架与围岩作用关系的稳定性,改善支架的端面控顶效果。采用ABAQUS软件分析了顶梁前后比、平衡千斤顶工作阻力和掩护梁压力对两柱掩护式放顶煤支架端面控顶效果的影响。研究表明,通过减小顶梁前后比、提高平衡千斤顶工作阻力和掩护梁压力,提高了立柱的支护阻力和梁端的支撑力,端面顶煤内拉应力减小,剪应力增大,端面顶煤稳定性增加,减小了端面顶板的下沉量。在此基础上,采用UDEC3.0分析了支架水平工作阻力对端面冒顶的控制作用。研究表明,硬煤端面区顶煤以拉断破坏为主,而软煤以剪切破坏为主。支架水平力可以减弱端面区顶煤的受拉程度,提高顶煤的抗剪能力,而且能够阻止端面冒落拱的发展,从而有利于保持端面顶煤的稳定性。采用物理模拟与数值分析的方法,研究了中等稳定以上类型直接顶回转变形与老顶回转变形的关系,给出了直接顶回转变形角的确定方法。通过把直接顶作为顶煤与支架系统的上部边界,建立了反映两柱掩护式放顶煤支架与围岩作用关系的力学模型。依据所建力学模型,分析了两柱掩护式放顶煤支架工作阻力的确定方法,给出了该架型支架工作阻力的计算公式。依据物理模拟与数值分析结果,分析了顶煤“双区失稳”的力学过程及其对支架适应性的影响,确定了支架适应性的判断参数,并给出了支架适应性的判断公式。现场实测分析了支架位态对支架适应性的影响。研究表明支架顶梁仰俯角度增大对端面冒顶的影响程度增强,据此给出了顶梁仰俯角的控制指标。采用实测方法对两柱掩护式放顶煤支架的现场应用进行了研究。研究表明,支架位态稳定,支撑效率高,端面顶板控制效果好,保障了工作面的安全高效生产。但受断层影响时,如果支架过断层时位态控制不当,会造成端面冒顶。因此,在该架型选型时,应考虑断层构造的发育及分布情况等,以发挥其控顶优势,提高生产效率。该论文有图209幅,表19个,参考文献139篇,其中外文文献24篇。更多还原

【Abstract】 With the maturity and popularization of fully-mechanized sublevel caving technique, fully mechanized sublevel caving face begins to develop towards automation and informationization. Two-leg sublevel caving shield is a new type hydraulic support and has been developed according to these development requirements. The new support has high support ability and good roof control effect in practice, and further improves the technology level of mechanized sublevel caving technique in China.Using analog simulation method that gives a research on dynamic function law of two-leg sublevel caving shield and surrounding rocks, it has been analyzed to the influence of top-coal hardness and main structure and parameters of the support on the function process. The study shows that in fully mechanized sublevel caving face the movement of top-coal has characteristics of "two-zone destabilization", its dynamic developing process influences the stability of the relationship between two-leg sublevel caving shield and surrounding rocks. Thus, two-zone destabilization which influences roof control effect of the support is the key factor. Increasing the working resistance of support and reducing the beam pre-to-post ratio can increase the stability of the relationship between support and surrounding rocks, and improve the roof control quality in tip-to-face area.The dissertation has analyzed the influence of the two-leg sublevel caving shield on roof control effect in tip-to-face area after the beam pre-to-post ratio, working resistance and the shield beam pressure have been simulated in ABQUS. After reducing pre-to-post ratio of the beam, increasing working resistance of the balance jack and/or pressure of the shield beam, the support resistance of the prop has been increased, the tensile stress has been reduced and shear stress in top-coal of tip-to-face has been increased. As a result, the stability of top-coal has been increased and roof sinkage has been reduced in tip-to-face area. According to the preceding result, the control effect of support horizontal resistance on roof fall of tip-to-face has further been studied using UDEC3.0.The study shows that hard top-coal of tip-to-face is mainly destroyed by tension, while the soft coal is mainly destroyed by shear. Support horizontal force can soften tension degree and increase shear capability in of top-coal in tip-to-face area, and prevent the development of the end caving arch. Therefore, the stability of top-coal in tip-to-face area can be maintained.The rotation deformation relationship between immediate roof above medium stability and main roof was studied by analog and numerical simulation method, and the determination method of turning angle of the immediate roof was put forward. Through making immediate roof the upper boundary of top-coal and support system, the mechanical model was constructed which reflects the core elements of the relationship between the two-leg sublevel caving shield and surrounding rocks system. According to the mechanical model, the determination method of the working resistance of the support was analyzed and the computational formula of the working resistance was induced.According to the analog and numerical simulation analysis result, the mechanical process of "two-zone destabilization" of top-coal and its influence on support applicability have been analyzed. The dissertation defines the determination factor for support applicability and induces the determination formula. By in-situ measurement the influence of support state on support applicability has been analyzed. The result shows that the influence of support on roof fall of tip-to-face gradually visualizes and enhances with the increase of upward or downward angle of the top beam, by which giving the control index of support state.The practical case has been studied in two-leg sublevel caving shield. The result of practical case showed the shape status and roof of tip-to-face were stable which met expectation effects. The efficiency of support is better than before. Therefore, this type of support can improve the efficiency of production and reliability of working face. However, when the working face enters into the fault zone, it shows that it is difficult to control the support, which could cause the roof fallen of tip-to-face. Therefore, it is necessary to select the appropriate support type according to geological condition of the top-coal in order to make most of its advantage and increase the production efficiency.The dissertation has 209 figures, 19 tables and 139 references including 24 foreign references.更多还原