综采工作面支架与围岩双周期动态作用机理研究
Double period dynamic mechanism of support and sur-rounding rock in fully mechanized mining face
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摘要: 为揭示液压支架与围岩的动态作用机理,将工作面开采过程分为若干个顶板活动周期,将每一个顶板活动周期分为若干个采煤循环周期,在研究支架载荷变化特征的基础上,综合“砌体梁”理论、弹性基础梁理论以及牛顿第二定律,提出了支架与围岩在双周期内的动态作用模型。在顶板活动周期内,研究认为“砌体梁”结构中的关键块A触矸是判断循环末阻力变化趋势的关键节点,关键块A触矸前循环末阻力逐渐增加,触矸后逐渐减小。在采煤循环周期内,研究认为“砌体梁”结构主要由煤壁、液压支架和采空区矸石组成的不同弹性模量支撑体共同承担,根据增阻特征的不同,将采煤循环内支架与围岩的作用过程分为给定变形和给定载荷两个阶段研究,提出了液压支架动态增阻函数,认为在给定变形阶段液压支架时间序列曲线符合对数函数,在给定载荷阶段符合指数函数。通过寺河矿及新元矿综采工作面实测数据分析,认为现场实测与理论分析结果一致。以上研究成果可为顶板灾害预测预报及顶板岩层控制实践提供参考。Abstract: In order to reveal the dynamic mechanism of shield and surrounding rock in a fully mechanized mining face, the mining process was divided into several roof active cycles and the every roof active cycle was divided into several mining cycles. The double period dynamic mechanism of support and surrounding rock was put forward,based on the bond-beam structure mechanical model,elastic base beam theory and Newton’s second law. During the roof active cy- cle,the results showed that the state of the block A in the bond-beam structure model touching the gangue was the key node to judge the variation trend of the final resistance. The resistance increased before the key block A touching the gangue,and reduced after touching. In the mining cycle,the study showed that the structure of bond-beam was mainly sustained by bases which have the different elastic modulus and composed of coal wall,hydraulic support and goaf. Ac- cording to the different increasing characteristics of the resistance,the interaction process of support and surrounding rock in mining cycle was divided into a given load stage and a given deformation stage,and the resistance function of dynamic increasing was put forward. The increasing curve in the given load stage followed an exponential function,and the curve in the given deformation stage followed a logarithmic function. The fitting results of the data measured in workface with the Sihe Mine and Xinyuan Mine,indicated that the field measurement was consistent with the theoreti- cal analysis. The above research would provide a theoretical basis for roof disaster prediction and strata control.