【作者】 丁飞；

【导师】 王春华；

【作者基本信息】 辽宁工程技术大学 ， 机械设计及理论， 2019， 博士

【摘要】 通常采煤机割煤高度3.5m～6.0m的工作面称为大采高综合机械化开采工作面,割煤高度≥6.0m的工作面称为超大采高综合机械化开采工作面。神东矿区上湾煤矿四盘区1-2煤层厚度5.35m～9.6m,平均厚度8.9m,采用综采一次采全高开采模式。超大采高综采工作面割煤高度大、强度高、煤壁易片帮、顶板易冒落,装备承受的载荷高、且动载冲击严重,液压支架作为工作面围岩结构稳定性控制的核心设备,其对围岩的适应性、稳定性和可靠性直接决定着超大采高综采技术的成败。本文针对这一问题,采用现场调研、理论分析、数值模拟、室内试验以及现场试验相结合的方法,开展了如下研究工作:(1)测定了神东矿区8.8m超大采高工作面煤岩物理力学性能参数,采用关键层理论研究了神东矿区超大采高工作面覆岩运动规律,分别以不同采高、不同工作面长度、不同支护强度为研究维度,研究了工作面矿压显现的规律,给出了初次来压步距和周期来压步距,提出了首采工作面长度,初步确定了工作面支护方式;(2)定量分析了影响煤壁片帮的主要因素,提出了煤壁片帮的力学判据;确定了神东矿区厚煤层超大采高工作面煤壁片帮的主要形式为剪切破坏,决定煤壁片帮的主要因素依次为采高、煤的力学性能、支护强度,计算得到工作面煤壁片帮高度和深度;研究了超大采高工作面片帮的概率分布,提出了煤壁片帮的概率分布函数;采用多目标优化的因素加权平均法构建了煤壁稳定性等级判定模型,确定了工作面稳定性等级属于稳定性中等煤壁;研究了工作面大煤块数量分布规律,提出了大煤块分布的数学模型,对开采过程中可能出现大煤块的数量进行了预测;(3)通过分析液压支架与围岩的强度、刚度和稳定性耦合关系,提出了支架对围岩的适应性,结合工作面的地质与力学条件,确定了超大采高液压支架的主要技术参数;研究了“煤岩—支架”耦合作用下影响护帮强度的主要因素,提出了防控措施;(4)对影响液压支架工作过程中横向和纵向稳定性的主要因素进行了定性和定量分析,建立了支架稳定性力学模型,给出了提高液压支架两向稳定性的措施;研究得到了超大采高液压支架多级伸缩立柱受压失衡的临界条件及判定依据;研究了立柱承载矿压等冲击载荷时的响应特征,提出了增加立柱抗冲击性能的技术措施;(5)分析了超大采高液压支架系统及部件可靠性的逻辑关系,对二柱式立柱和四柱式立柱的可靠度进行了比较,对选用二柱式方案提供了理论依据;分析了液压支架顶梁、掩护梁、连杆、底座的剪切力、拉力、扭矩和弯矩情况,以及支架设计缺陷可能存在区域,并对支架复杂受力工况和可靠性与寿命进行了分析;对支架顶梁柱窝周边应力应变集中区域的试验样本数据采用Bootstrap方法进行重抽样分析,给出了应力正态均值和方差的计算方法。论文研究工作对于超大采高一次采全高综采工程实践有较好的理论和实际意义。该论文有图66幅,表25个,参考文献155篇。更多还原

【Abstract】 Generally,the working surface with cutting height of 3.5m～6.0m was called fully-mechanized working surface with large mining height,and the working surface with cutting height of more than 6.0m was called fully-mechanized mining face with super-large mining height.The thickness of coal seam 1-2 in the fourth panel of Shangwan in Shendong coal mine was 5.35m～9.6m,and the average thickness was 8.9m.With the adoption of one-time and full-height mode of comprehensive mechanized mining.Fully-mechanized working surface with super large mining height had several characteristics,such as the cutting height and strength of coal was high,the coal wall formed rib spalling easily,the roof caved easily,the load of the equipment was high and dynamic impact load was serious.Hydraulic support was the core equipment for controlling the structural stability of surrounding rock in working surface.Its adaptability,stability and reliability to surrounding rock directly determined the success or failure of fully-mechanized mining technology with super-large mining height.According to this problem,this paper adopted the method of job-site survey,theoretical analysis,numerical simulation and the combination of indoor test and field test,and the following researches were carried out:(1)This paper measured physical and mechanical properties of 8.8m high working surface coal in Shendong mining area.The overburden movement law of fully-mechanized working surface with super large mining height in Shendong mining area was studied by using key stratum theory.Taking different mining heights,different working face lengths and different support strengths as research dimensions,the law of rock pressure appearance of working surface was studied.The first weighting step,periodic weighting step and the length of the first mining surface were determined.Also the support strength of working surface is preliminarily determined.(2)Quantitatively analyzed the main factors that affected rib spalling,and proposed the mechanics basis of rib spalling.It was determined that shear failure was the main form of formation of rib spalling in fully-mechanized working surface with super large mining height in Shendong mining area.The main factors affecting rib spalling were mining height,mechanical properties of coal and support strength.The height and depth of rib spalling were calculated.This paper studies the probability distribution of rib spalling on the working surface with super large mining height,and proposed the probability distribution function of rib spalling.Muti-objective optimization of factor weighted average methods was used to construct the decision model of coal wall stability grade,and the stability grade of working surface was determined,which belonged to medium stability coal wall.Then this paper studied the quantitative distribution of large coal cinder and proposed its mathematical model,predicted the possible quantities of large coal cinder in the process of mining,which provided data support for the design and selection of equipment in fully-mechanized mining working surface.(3)By analyzing the coupling relationship between hydraulic support and the strength,stiffness and stability of the surrounding rock,proposing the adaptability of support to surrounding rock,and combing the geological and mechanical conditions of working surface,this paper determined the main technical parameters of hydraulic support with great height.Further more,this paper studied the main factors that affected the strength of rib spalling under the coupling effect between coal and rock,and proposed several prevention and control measures.(4)In order to establish a mechanical model for the stability of support and propose several measures to increase the bidirectional stability of hydraulic support,qualitative and quantitative analysis was also needed to research the main factors that affected the transverse and longitudinal stability in the working process of hydraulic support.The multistage telescopic column of hydraulic support with great height was unbalanced under pressure,by studying that,the critical condition and judgement basis could be obtained.The columns bore the impact loads such as rock pressure,by studying the response characteristics,we could propose several technical measures to increase the impact resistance of columns.(5)Besides,this paper analyzed the logical relationship of reliability between hydraulic support system and its components,and made a comparison of reliability between two-column and four-column pillars,which provided a theoretical basis for choosing the two-column scheme.This paper separately analyzed the shear force,stretching force,torque and bending moment of roof beam,caving shield,connecting rod and foundation plate of hydraulic support.This paper also analyzed the reliability,life and the complex loading condition,as well as the possible areas where design defects may existed.The Bootstrap method was used to do the re-sample analysis of data collected from the stress-strain concentration area around the pillar of the support roof beam.This paper also used the computing methods of normal stress mean value and variance,and the result had high accuracy and reliability.The research work in this paper is of great theoretical and practical significance to the full-mechanized mining engineering of ultra large mining height working face.This paper consists of 66 pictures,25 tables and 155 reference documents.更多还原