Prediction model for increasing resistance of hydraulic support due to slow motion of the roof in mechanized mining working face
XU Gang,ZHANG Chunhui,ZHANG Zhenjin
检修和停产期间综放工作面顶板缓慢活动易引发压架灾害，预测检修和停产期间覆岩活动和支架工作阻力演化是相应压架灾害防治的关键。将综放工作面支架上方顶煤、直接顶和基本顶视作整体宏观顶板，引入广义开尔文模型模拟综放工作面宏观顶板的缓慢活动及其对支架工作阻力演化的影响，建立了综放工作面宏观顶板缓慢活动增阻预测模型。利用该模型预测了陕西宝鸡崔木煤矿303综放工作面液压支架工作阻力演化，分析了初撑力和宏观顶板性质对顶板缓慢活动和支架工作阻力演化的影响，结果表明：① 宏观顶板缓慢活动增阻预测模型能较好地预测工作面检修和停产期间支架增阻。② 模型中参数E2描述了宏观顶板的软硬。E2越大，宏观顶板越坚硬，初撑后宏观顶板下沉量小，支架增阻力也小。③ 初撑力增加，宏观顶板的E2值近似线性增加，支架增阻力近似线性减小。增大初撑力，能够提高宏观顶板的完整性，降低宏观顶板缓慢活动引起的增阻力。④ 宏观顶板黏滞系数η主要影响支架工作阻力随时间演化曲线的形态。η越大，支架阻力演化曲线收敛越慢。⑤ 将多个支架（或循环）的计算参数均值与本文宏观顶板增阻预测模型结合，可以预测工作面支架工作阻力演化行为。
The support crushing disaster easily occurs due to the roof slow motion of fully mechanized caving face during the maintenance and halting production.It is a key issue to predict the evolution of the hydraulic support work resistance and overburden for the prevention and control of the support crushing disaster.The top coal,the immediate roof and the basic roof above the support of a fully mechanized top coal caving face were considered as overall macro roof.The generalized Kelvin model was employed to predict the slow motion of the macroscopic roof and the support working resistance evolution due to the slow motion in mechanized mining working face,and the increasing resistance predicting model due to the slow motion of the macroscopic roof was established.The hydraulic support working resistance evolution at the 303 fullymechanized work face in Cuimu coal mine was predicted using the model proposed in this paper.The effects of the initial supporting force and the mechanical properties of macro roof on the slow motion and support working resistance evolution were investigated,and the results show that:① the increasing resistance evolution of hydraulic support during maintenance and halting production of working face can be well predicted by the predicting model in this paper.② The parameter of E2 in the predicting model presented in this paper is used to describe whether macro roof is soft or hard.The larger E2 is,the harder the macro roof is,and the smaller the subsidence of the macro roof and the resistance of the support after initial support is.③ With the initial support force increase,the E2 of the macro roof increases linearly,however the increasing resistance decreases approximately linearly.Increasing the initial support force can improve the integrity of the macro roof and reduce the increasing resistance due to the slow motion of macro roof.④ The viscosity coefficient,η,mainly influences the shape of the working resistance evolution curve with time.The larger ηis,the slower the evolution curve converges.⑤ Combining the mean calculation parameters of many supports (or cycles) and t the increasing resistance predicting model of the macroscopic roof in in this paper,the evolution behavior of working resistance of support in working face can be predicted.
increasing resistance predicting model,evolution of support work resistance,slow movement,mechanizedmining working face,Generalized Kelvin model