掘进工作面围岩稳定性分析及快速成巷技术途径

Analysis on stability of rock surrounding heading faces and technical approaches for rapid heading

  • 摘要: 分析了煤矿巷道掘进技术与装备现状及存在的问题,采用数值模拟方法研究了掘进工作面围岩应力、变形、破坏分布特征;分析了围岩稳定性的主要影响因素,包括围岩强度、围岩结构及地应力等地质力学参数,巷道断面尺寸、开挖方式、空顶距、掘进速度等掘进参数,及临时支护、永久支护等。巷道开挖后在掘进工作面顶角和巷道四角周围出现应力集中区;围岩位移、破坏在超前工作面一定位置开始出现,随着远离掘进工作面围岩位移和破坏范围不断增大,达到2倍巷道宽度时基本稳定;煤层强度、地应力对围岩变形与破坏的影响十分显著;分步开挖的顶板下沉量及破坏程度明显大于一次开挖;空顶距越大,围岩破坏裂隙越多、分布越广;过快、过慢的掘进速度对围岩稳定性均不利;掘进后安装及时、主动、支护阻力大的临时支护效果好;分次支护围岩位移和裂隙场的扩展均大于一次支护,通过分次支护提高掘进速度是以影响锚杆支护效果为代价的,应限定在一定的围岩条件。根据煤巷掘进工作面空顶距及自稳时间,对煤巷掘进工作面围岩稳定性进行了分类,并提出了相应的支护要求;提出煤巷可掘性的概念,根据被掘煤岩体条件,对煤巷可掘性进行了分类;分析了围岩的可钻性、可锚性及对掘进速度的影响。提出提高煤巷掘进速度的主要技术途径:确定适合的掘进模式,优化掘进工艺,优选掘进装备;确定合理的支护形式与参数,适当降低支护密度;掘进全系统整体配套与协同。根据掘进工作面围岩稳定性、可掘性、可钻性及可锚性,提出煤巷掘进自动化、智能化技术总体架构及应解决的关键技术:自动化、智能化截割、临时支护、自动化锚杆施工、超前探测、定位与导航、围岩稳定性与环境监测及大数据分析等,最后提出我国煤巷掘进自动化、智能化的发展路径。

     

    Abstract: Analyzes the current status and problems of coal mine roadway heading technology and equipment.The main influencing factors of the stability of surrounding rocks are analyzed,including geomechanical parameters such as surrounding rock strength,surrounding rock structure and in situ stress,excavation parameters such as roadway section size,excavation method,unsupported roof distance and excavation speed,as well as temporary support and permanent support.After excavation,the stress concentration zone appears around the top corner of the excavation face and the four corners of the roadway.The displacement and damage of the surrounding rock starts to appear at a certain position in front of the excavation face,and increases as it moves away from the excavation face,and basically stabilizes when it reaches twice the width of the roadway.The influence of coal seam strength and in situ stress on the deformation and damage of surrounding rock is very significant.The amount of roof sagging and the damage degree of staged excavation is obviously larger than that of one-time excavation.The larger the unsupported roof distance,the more cracks and the wider distribution range of fractures in surrounding rock.Too fast and too slow excavation speed is not good for the stability of surrounding rock.The temporary support with timely,active and large support resistance is good for the stability of surrounding rock.The displacement and fracture field of surrounding rock by support for several time is greater than that of support once,and the increase of excavation speed by support for several time is at the cost of affecting rockbolting effect,which should be limited to certain surrounding rock conditions.According to the unsupported roof distance and self stabilization time of the heading face within coal seams,the stability of surrounding rock is classified and the corresponding support requirements are proposed.The concept of excavability of coal roadway is proposed and the excavability of coal roadway is classified according to the conditions of the excavated coal measures.The drillability and anchorability of surrounding rock and the influence on excavation speed are analyzed.The main technical measures to improve the heading speed of coal roadway are proposed:to determine the suitable excavation mode,optimize the excavation process and select the excavation equipment;to determine the reasonable support form and parameters and appropriately reduce the support density;and to mach and coordinate the whole system of heading.According to the stability,excavability,drillability and anchorability of surrounding rock,the overall structure of coal heading automation and intelligent technology is proposed,and the key technologies should be solved:automatic and intelligent cutting,temporary support,automatic bolt installment,adcanced detection,positioning and navigation,surrounding rock stability and environmental monitoring and big data analysis,etc.Finally,the development path of coal heading automation and intelligence in China is proposed.

     

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