【作者】 范志忠；

【导师】 齐庆新； 王家臣；

【作者基本信息】 中国矿业大学(北京) ， 采矿工程， 2019， 博士

【摘要】 针对国内大采高工作面普遍存在的煤壁片帮、漏顶、支架压垮等一系列围岩控制难题,论文选取了国内有代表性的10个不同赋存条件的大采高工作面为研究对象,采用实验室试验、数值模拟、现场观测、理论分析等手段,从围岩控制角度研究了大采高由于工作面长度、采高、煤层倾角、埋深、构造、煤岩物理力学性质等因素变化所产生的各种尺度效应。论文形成如下认识:在采高尺度上,研究得出煤体强度随采高增加呈对数曲线下降趋势,进一步分析认为煤样动载试验(SHPB)得出的峰值强度较单轴抗压强度更能准确反映现场煤体的稳定性;分别从应力变化和能量耗散角度对片帮机理进行了研究,认为煤体最大水平主应力卸荷幅度与煤壁损伤呈正相关关系;通过建立采场上方关键层挠度函数,得到了不同采高下支撑压力区应力场分布规律,量化了采高的尺度效应;通过对煤壁前方能量场进行模拟和反演,得到了不同采高煤壁损伤与能量释放幅度间的对应关系。在工作面长度尺度上,基于矿压显现的差异性,分别得出了浅埋煤层、深部开采、大倾角煤层、伪斜开采四种条件下工作面长度或倾角方向上的尺度效应;浅埋煤层方面,研究认为其工作面长度尺度效应不明显,围岩控制的关键在确保于工作面支护强度和推进速度的匹配性,将松散层载荷的传递效率定义为时间因子,实现了推进速度和工作面长度之间耦合作用的定量化分析;深部开采方面,研究认为其顶板压力随工作面长度增加呈典型的“双峰”或“多峰”分布,老顶关键层在工作面长度上表现为分区域折断特征,工作面大周期来压与瓦斯超限呈现一致性增减关系,工作面长度尺度效应较明显;大倾角开采方面,研究认为大倾角工作面存在“临界长度”,将工作面沿倾向分为充填段、易溃屈段和滑移段结构,进一步得出了大倾角工作面支护强度确定方法;伪斜开采方面,研究认为工作面存在临界伪斜角度,煤层倾角与工作面适用伪斜角呈指数曲线关系,煤层倾角越大,则适用伪斜条件的角度比例越小,工作面伪斜角度有其适用区间。对于多因素耦合围岩控制尺度效应分析方面,尝试建立了基于熵值理论的开采强度分析模型,采用属性识别法有效解决了工作面赋存条件和开采条件评价指标相邻区间的有序分割问题,实现了不同赋存条件大采高工作面开采强度的横向对比,以及工作面围岩控制的多因素耦合尺度效应分析。在采场围岩失稳尺度效应监测与预警技术方面,研究建立了支架位态识别模型,通过位态的变化反演支架灾变前的荷载特征,提出了基于支架位态识别的预警指标体系与方法,试制了预警软件和硬件系统,成功进行了现场试验。本论文的研究成果,在阳煤集团一矿的8310、8303和81303三个不同赋存条件大采高工作面回采中得到了成功应用。更多还原

【Abstract】 Aiming at a series of surrounding rock control problems commonly existing in large mining height working face in China,such as coal wall slice,roof leakage and support collapse,this thesis selected 10 representative large mining height working face with different occurrence conditions as the object,and studied the large mining height working face because of its long face from the angle of surrounding rock control by means of laboratory test,numerical simulation,field observation and theoretieal analysis.Various scale effects caused by changes in mining height,coal seam dip,burial depth,structure,physical and mechanical properties of coal and rock.The results of this thesis are as follows:In the direction of mining height,it is considered that the strength of coal body decreases logarithmically with the increase of mining height.The peak strength obtained by SHPB can reflect the stability of coal body more accurately than that obtained by uniaxial compressive strength.The mechanism of slice side is studied from the angle of stress change and energy dissipation.It is considered that the unloading range of maximum horizontal principal stress and residual energy of coal body are in positive phase with the damage of coal wall.By establishing the deflection function of key strata,the stress distribution characteristics of the area affected by the advance support pressure under different mining heights are obtained.Through the simulation and inversion of the energy field in front of the coal wall,the corresponding relationship between the damage and energy release of the coal wall at different mining heights is obtained.In the direction of working face length,based on the difference of rock pressure appearances,the scale effects of working face length or dip direction under four conditions of shallow seaxn,deep mining,large dip seam and pseudo-dip mining are obtained respectively.For shallow coal seam,the key of surrounding rock control is to ensure the matching of support strength and advancing speed.The transmission efficiency of loose layer load is defined as a time factor,and the quantitative analysis of coupling effect between advancing speed and working face length is realized.In deep mining,it is eonsidered that the distribution of roof pressure is typical "double peak" or "multi-peak" with the increase of working face length,the key strata of old roof are characterized by regional breakage in the length direction of working face,and the relationship between large periodic weighting and gas exceeding limit in working face is consistent.In the aspect of mirung with large dip angle,it is considered that there is "critical length" in the working face with large dip angle.The working face is divided into filling section,collapsible buckling section and slip section along the inclination,and the method for determining the support strength of the working face with large dip angle is further obtained.In the aspect of pseudo-inclined mining,it is considered that the relationship between the dip angle of coal seam and the applicable pseudo-inclined angle of working face is exponential curve.The bigger the dip angle of coal seam is,the smaller the proportion of the applied pseudo-inclined angle is.The pseudo-inclined angle of working face has its applicable range.For multi-factor and multi-scale coupling coal seam conditions,an evaluation model of mining intensity based on the theory of entropy value is established.The problem of orderly division of adjacent intervals of evaluation indexes of mining conditions and occurrence conditions is effectively solved by using attribute recognition method,and the horizontal comparison of mining intensity of high mining height working face with different occurrence conditions is realized.In the aspect of roof disaster monitoring and early warning,this thesis studies and establishes the support position recognition model,inverts the load characteristics of the support before the catastrophe through the change of the position,puts forward the early warning index system and method based on the support position recognition,develops the early warming software and hardware system,and carries on the successful test in the field.The research results of this thesis have been successfully applied in the mining of high mining height working face with 8310,8303 and 8103 different occurrence conditions in No.1 Coal Mine of Yangquan Coal Group.更多还原