大采高综放工作面支架动态响应特征研究及应用

Study and application of dynamic response characteristics of support in full-mechanized top coal caving with large mining height

  • 摘要: 采场支架动态响应特征包含支架增阻、活柱下缩等信息,是反映工作面矿压显现强度的重要指标,也是研究支架与围岩动态相互作用关系的基础。以曹家滩煤矿122108工作面为例,采用理论分析、数理统计等方法,明晰回采过程支架动态响应特征,揭示不同承载阶段支架增阻机制,实测分析工作面压裂前后矿压显现特征,并开展了来压前后支架增阻特性研究与应用。结果表明:在连续多个循环中,支架呈“高阻力且活柱持续下缩”特征则说明工作面来压,可利用支架下缩信息评价历次来压的显现强度;顶板未断裂时,运用广义开尔文模型能较好地表征该时期顶板的缓慢活动;顶板断裂后,给定变形阶段支架呈对数型增阻,增阻速率由支架刚度、控顶距、断裂顶板失稳状态共同决定,给定载荷阶段支架呈指数或线性型增阻;采用支架工作阻力与高度双因素分析法能准确判断强矿压工作面矿压显现特征,压裂后工作面30 m以上大来压步距占比大幅减小,10~28 m来压持续距离占比降至2%,支架累计下缩量、下缩速度正态分布曲线整体降低;支架增阻类型、增阻速率的变化是判断工作面来压与否的一个显著特征,可作为预测工作面来压的新手段;运用支架均化增阻结果可预测顶板压力、反演顶板宏观下沉变化。以上研究成果对于完善支架与围岩的相互作用关系,指导工作面顶板灾害预警与防治具有一定的参考意义。

     

    Abstract: The dynamic response characteristics of stope support include the information of support resistance increase and live column shrinkage, which is not only an important index to reflect the strength of mining pressure behavior in working face, but also the basis for studying the dynamic interaction between support and surrounding rock. Taking the 122108 working face of Caojiatan Coal Mine as an example, heoretical analysis and mathematical statistics were used to clarify the dynamic response characteristics of the support during the mining process, reveal the resistance increasing mechanism of the support in different bearing stages, and analyze the characteristics of mining pressure before and after fracturing of the working face, and carry out research and application of the resistance increasing characteristics of the support before and after pressure. The results show that: in continuous cycles, the support shows the characteristics of “high resistance and continuous shrinkage of the living column”, then the working face is pressed, and the information of support shrinkage can be used to evaluate the apparent strength of the previous pressure. When the roof is not broken, the generalized Kelvin model can be used to characterize the slow movement of the roof. After the roof fracture, the support shows a logarithmic resistance increase at a given deformation stage, and the resistance increase rate is determined by the support stiffness, the controlled roof distance and the unstable state of the broken roof, and the support resistance increases exponentially or linearly at the given load stage. The dual-factor analysis method of support resistance and height can accurately judge the characteristics of mine pressure behavior in the working face with strong mine pressure. After fracturing, the proportion of the pressure step distance of more than 30 m in the working face is greatly reduced, and the proportion of the continuous pressure distance of 10 to 28 m is reduced to 2%. The normal distribution curve of cumulative shrinkage and shrinkage speed of support decreases as a whole. The change of the type and rate of resistance increase of support is a remarkable feature to judge whether the working face is under pressure or not, and it can be used as a new method to predict the pressure of working face. The result of increasing resistance by homogenization of support can be used to predict roof pressure and invert the macroscopic subsidence change of roof. The above research results have certain reference significance for improving the interaction between support and surrounding rock and guiding the early warning and prevention of roof disasters in working face.

     

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