放煤过程中液压支架顶梁动态载荷演化特征试验研究

Experimental study on the evolution characteristics of dynamic load of hydraulic support top beam during coal caving

接触式煤矸识别需要研究综放开采液压支架顶梁承载特性,但现有研究大多重点关注放煤前后的支架承载特性或在给定载荷情况下支架的力学响应特征,忽略了对放煤过程中载荷变化的深入探究。针对上述问题,搭建了放顶煤支架动态载荷相似模拟试验平台,借助散体颗粒模拟破碎煤矸块体,反演了综放工作面放煤过程,利用薄膜压力传感器采集支架顶梁压力,分析了放煤过程中顶梁动态载荷演化特征。试验结果表明:①顶煤的放出对支架顶梁载荷产生了较为明显的影响,即随着顶煤放出,支架顶梁载荷整体呈先增大后减小最终稳定的演化规律。②沿顶梁长度方向,支架顶梁距离掩护梁越远的位置受顶煤放出的影响越小,主要表现在距离掩护梁越远,顶梁载荷峰值相较初始值的增幅越小,且达到载荷峰值所需的时间越长。③沿顶梁宽度方向,由于顶煤的放出过程受到了约束边界或流动过程不均衡性的限制,顶梁不同位置的载荷峰值具有差异性,顶梁载荷峰值相较初始值的增幅最大值达到了最小值的2.4倍。

Contact coal-gangue identification requires studying the bearing characteristics of hydraulic support top beams in fully mechanized top coal caving.However,existing research primarily focuses on the bearing characteristics of supports before and after coal caving or the mechanical response characteristics of supports under given loads,neglecting an in-depth exploration of load changes during the coal caving process.To address this issue,a dynamic load similarity simulation test platform for top-coal hydraulic supports was established,using granular particles to simulate broken coal gangue.This setup simulated the coal caving process in a fully mechanized working face,and thin-film pressure sensors were employed to collect pressure data from the support top beams.The dynamic load evolution characteristics of the support top beams during the coal caving process were analyzed.The experimental results indicated:①The caving of top coal significantly affected the load on the support top beams,demonstrating an evolution pattern where the overall load first increased,then decreased,and finally stabilized as the top coal was released.②Along the length of the beam,the locations of the support top beams farther from the protective beam were less affected by the caving of top coal.This was primarily reflected in the smaller increase in peak load compared to the initial value at locations farther from the protective beam,as well as a longer time required to reach the peak load.③Along the width of the beam,due to the constraints of boundary conditions or the unevenness of the flow process during top coal caving,the peak load at different positions of the beam showed variability,with the maximum increase in peak load compared to the initial value reaching up to 2.4 times the minimum increase.