【作者】 张向阳；

【导师】 谢广祥；

【作者基本信息】 安徽理工大学 ， 采矿工程， 2013， 博士

【摘要】 本文基于采场围岩中存在由“高应力束”组成的应力壳理论,运用实验室相似模拟、计算机数值模拟、理论分析等研究方法,以采场大范围围岩为研究对象,开展了非对称开采采场围岩应力场、破坏场及位移场演化特征的煤柱宽度效应研究,进行了采场围岩支承应力形成和发展的分析计算和临空区煤柱宽度变化对其影响规律研究,实例分析表明运用此种方法分析计算采场围岩支承压力、研究煤柱宽度对采场围岩支承压力的影响规律是可行的。采用实验室相似模拟试验和计算机FLAC3D数值模拟软件,研究了不同临空区煤柱宽度情况下,采场围岩三维应力场演化特征及几何形态变化规律。研究表明：采场围岩应力分布自前向后应力壳倾向剖面几何形态由n型“单壳”逐渐向m型“复壳”演化,“单壳”壳基应力峰值大于“复壳”壳基应力峰值。对于深部非对称开采,随临空区煤柱宽度增大,工作面前方应力壳壳基位置由风巷下帮煤体逐渐向煤柱侧转移,在煤体和煤柱上的应力峰值逐渐升高,当煤柱宽度增加到一定宽度后,风巷下帮煤体应力峰值升高不再明显,煤柱承担上覆岩层大部分荷载；工作面后方应力壳为“复壳”形态时,随煤柱宽度增大,煤柱上方壳基位置由上提形态逐渐回落,进而与煤柱内应力峰值位置叠加。研究了对不同临空区煤柱宽度情况下,采场三维围岩破坏场和位移场演化特征。研究表明：随着煤柱宽度的增大,在上区段工作面和本区段工作面的上覆岩层垮落高度都逐渐减小；在工作面前后不同位置的围岩倾向剖面破坏区范围,在风巷下侧煤体及其上覆岩层中,随煤柱宽度增大此区域逐渐减小；煤柱宽度变化对工作面前方15m处围岩变形破坏影响明显。随着煤柱宽度的增大,风巷上帮垂直位移量逐渐减小,而下帮垂直位移量则逐渐增大；风巷上帮沿倾向水平位移量逐渐增大,而下帮沿倾向水平位移量则逐渐减小；煤壁位移主要发生在工作面上部距风巷15m左右距离处,沿倾向水平位移量逐渐增大,沿走向水平位移量逐渐减小,而垂直位移量先增大后减小,15m煤柱宽度时垂直位移量达到最大。在工作面由前至后不同位置,巷道围岩位移呈现阶段性特征,倾向剖面上覆岩层变形移动最大位置区域由上区段采空区逐渐向本区段工作面中上部采空区转移。分析了深部采场推进期间的应力分布演化特点和围岩受力破坏规律。分析得出在采场开切眼形成后及顶板未断裂之前,围岩受力及集中区分布范围较小,顶板岩层经历从稳定状态逐渐向断裂临界状态逼近的过程；随着采煤工作面的持续推进,顶板周期性垮落,采空区顶、底板应力降低区范围在高度和宽度上都不断扩大,围岩应力集中区域形态在走向剖面呈拱形,三维立体形态呈椭球形壳；当工作面推进长度是倾向长度的1～1.2倍左右时,应力壳高度达到最大,并与工作面倾向长度相当。基于非对称开采围岩存在应力壳的基本观点,根据深部采场围岩三维应力场的应力分布和覆岩运动破坏特征,建立了采场围岩支承压力与应力壳几何参数关系的计算模型,获得了不同区域支承压力与应力壳几何参数关系表达式,实例分析表明运用此种方法分析计算采场围岩支承压力、研究煤柱宽度对采场围岩支承压力的影响规律是可行的。研究成果丰富了矿山压力理论,为有效预防采场围岩应力转移导致的围岩失稳及其他动力灾害提供了理论依据,对煤矿采场布局、工作面支架选型、采场围岩控制、临空区煤柱留设及动力灾害控制和实现安全高效开采具有重要指导意义。更多还原

【Abstract】 In this paper, comprehensive research methods, including numerical and physical modeling tests, theoretical and case analysis, are carried out to investigate into the following details based on the surrounding rock stress shell theory from large-scale and three-dimensional space:(i) coal pillars width effect on the evolution characteristics of the surrounding rock stress field, damage field and displacement field in asymmetric mining;(ii) the surrounding rock abutment pressure forming and developing in the mining face, and its distribution patterns affecting by the coal pillar width. The results show that it is feasible to analyze and calculate the surrounding rock abutment pressure, study the influence of its distributing laws on the adjacent goaf coal pillars width by the methods.The surrounding rock3D stress field evolution characteristics and geometry change rules around coal mining face are demonstrated with different adjacent goaf coal pillars width. The results indicate that the surrounding rock stress distribution geometrical morphology in dip section tended to evolve gradually from the n type "single-shell" to the m type "duplicate-shell" by the former backward. The "single-shell" peak stress is obvious greater than the "duplicate-shell" peak stress. And with the increase of adjacent goaf coal pillars width, the shell base location transfer gradually from the lying side coal of return airway to the coal pillar side. The peak stress in coal and coal pillar are gradually rise, when the coal pillar width is7m, the stress peak value is higher in the lying side coal of return airway, the peak location is located from the lying side of return airway around10m. when the coal pillar width is7m, the stress peak value is higher in the20m ahead of working face along the strike direction. When the coal pillar width is15m, the peak stresses is higher in the coal pillar. Behind the working face, with the increase of the coal pillar width, the shell base position above the coal pillar fall back gradually, and superimposed with the stress peak position of the coal pillar.The evolution characteristics of the3D surrounding rock damage field and displacement field in the different adjacent goaf coal pillar width are obtained. The results indicate that the caving height of overlying rock decrease gradually with the increase of coal pillar width. With the coal pillar width increase, the surrounding rock damage zone in the dip section before and behind the working face decrease gradually in the lying side coal of return airway and overlying rock. The change of coal pillar width has a great influence to the surrounding rock deformation and fracture in15m front of the working face. With the increase of coal pillar width, the vertical displacement of the return airway upper side decrease gradually, and the vertical displacement of the return airway lying side increase gradually, the tendency horizontal displacement of the return airway upper side increase gradually, and the horizontal displacement of the return airway lying side increase gradually; the coal wall displacement occurs mainly in the upper face15m distance away from the return airway, along the tendency to horizontal displacement increase gradually, along the strike the horizontal displacement decrease, while the vertical displacement first increase then decrease, when the coal pillar width are15m the vertical displacement reach the maximum value.In the different position of the working fac from before to behind, the displacement of surrounding rock appear the stage characteristics, in the dip section the largest deformation location area of overlying rock transfer from the upper sector goaf to the middle and upper goaf of the working face.Stress evolution distribution characteristics and surrounding rock mechanical failure laws are analyzed with the face advance in deep mining.After open-off cutting and before roof breaking, surrounding rock mechanical distribution range is less, it mainly presents the characteristics that regional range is small and coal seam and strata gradually approach critical state of roof breaking from stable state. With face advancing, roof periodically caves, stress-relaxed area of goaf roof and floor constantly enlarges in height and width, regional morphology of stress concentration presents an arch of strike profile and its3-dimensional morphology presents an arched shell. When working surface advancement length is1～1.2times than width, height of stress shell reaches the maximum and is to equal width of working face. Goaf gangue and strata which is not completely broken in stress shell and stress-relaxed area undertake strata in stress-relaxed area above goaf, which goaf gangue undertakes most of strata in stress-relaxed areaBased on the basic viewpoint of stress shell in surrounding rock of asymmetric mining, calculation model of relationships between geometrical parameters of abutment pressure and stress shell are established according to stress distribution of3D stress field of surrounding rock and overburden movement failure characteristics in deep mining, and relational expression of geometrical parameters of theirs in different regions are obtained. The example analysis shows that it is feasible to calculate surrounding rock abutment pressure and study influence law of surrounding rock abutment pressure affected by coal-pillar width with this method.Research results enrich the theory of strata pressure, it provides theoretical basis for the effective prevention of surrounding rock instability and other dynamic disasters. It has important guiding significance to the coal minng face layout, supports selection, the surrounding rock control, coal pillar width choice, dynamic disasters control and achieve to the safe and efficient mining.更多还原