【作者】 蔡来生；

【导师】 俞焕然；

【作者基本信息】 兰州大学 ， 固体力学， 2009， 博士

【摘要】 地下开采改变了围岩的应力分布状态,进而影响到围岩的位移以及破坏场分布,降低了围岩的稳定性,因此充分认识地下开采引起的围岩应力变化,选用有效的支护措施是确保围岩稳定的关键所在。本文以窑街煤电有限责任公司天祝煤矿为研究背景,对矿区内大倾角坚硬厚煤层综放工作面开采技术、采空区下薄顶煤大断面巷道支护技术及优化展开了多方位、全方面研究,获得了丰硕的研究成果。大倾角综放工作面通过相似材料模拟试验研究,揭示了在倾斜方向上,采空区顶板运动和断裂具有明显的非对称性冒落与充填特征,老顶岩层在倾斜方向上可形成铰接拱梁结构,总体上可分为四个特征区,由上山向下山侧依次分为:Ⅰ、自由冒落区;Ⅱ、上拱脚支承区;Ⅲ、老顶岩层铰接区;Ⅳ、下拱脚支承区。数值计算方法进一步揭示了大倾角综放工作面倾斜剖面上应力拱的形态。工作面上方存在的应力拱结构下拱脚位于沿煤层倾向工作面下端煤层和附近底板岩层中,上拱脚位于沿煤层倾向工作面上部顶煤和直接顶中,应力拱中的最大主应力高于拱内外岩层中的应力。应力拱是主要的承载体,上覆岩体荷载和压力通过应力拱传递到工作面上下隅角位置,形成上下顺槽附近的支承压力。综放面位于应力拱保护下的低应力区内,这是综放面主要的力学特征。对大断面薄顶煤巷道,采用FLAC和UDEC程序建立地质模型,证明了在该环境下开掘巷道的可行性,并对巷道的锚网支护设计进行了深入研究。利用正交试验方法研究了巷道支护锚杆间距、排距、直径等关键因素对支护效果的影响;采用极差分析法揭示了各关键因素对支护效果的影响程度;运用模糊理论和灰色关联理论对支护方案进行了优化;采用数值模拟方法对优化支护方案的支护效果进行了验证。通过对大断面薄顶煤巷道围岩压力分布规律的数值模拟研究,为采空区边缘回风巷合理位置的选择提供了理论依据,在此基础上设计了切实可行的支护方案。采用多种监测技术手段,对巷道不同顶煤厚度条件下围岩的压力、变形和破坏进行现场监测,对锚网联合支护效果进行评价。揭示了不同顶煤厚度条件下巷道周围压力分布、围岩移动变形与破坏规律,同时验证了巷道控制的必要性、有效性和安全性。本文在大倾角坚硬煤层综放开采技术研究以及采空区下薄顶煤大断面巷道锚网联合支护技术研究中取得了新的认识和发展,获得了丰硕的理论、实验研究和工程成果,富有理论价值和实际指导意义。更多还原

【Abstract】 The distrubitions of the stresses, displacements and failure zones in the wall rocks are affected by underground mining. The stability of the wall rocks becomes weaker due to underground mining. It is important to realize the variations of stresses in the wall rocks for adopting reasonable support measures.In this thesis, the fully-mechanized coal mining with sub-level caving in high steep coal seams and the support technologies in lanes with thin coal roof are studied on the basis of TianZhu mining. Many resaeach finfings are acquired.The similar simulation test on work face using the fully-mechanized coal mining with sub-level caving suggests the movement and breaking of the roof are asymmetric in the inclined cut. The main roof caving can perform articulated roof beam in the inclined cut. It is divided into four parts from uphill direction to downhill direction. I is free caving zone, II is up arch-foot support zone, III is articulated zones, and IV is down arch-foot support zone.Numerical analysis are completed to study the distrubition of stress arch in the inclined cut in work face using the fully-mechanized coal mining with sub-level caving. There is stress arch upon the work face in the inclined cut. The down arch-foot is in the down coal seams and rocks in the inclined cut. The up arch-foot is in the roof coal seams and rocks in the inclined cut. The maximum principle in stress arch is higher than the rocks out of the stress arch. The stress arch is main support body. The load and pressure in hanging strata are carried to the down corner of the work face to perform support pressure near gate stull through the stress arch. The main mechnics feature is that the work face using the fully-mechanized coal mining with sub-level caving is in the low stress zones under the stress arch.The Flac and UDEC projects are used to construct geological model of the lanes with thin roofs. It is feasible to make lanes in this surrounding. The support technologies of bolting with wire mesh are used and studied. The effects of spacing, distance between rows and diameter of bolts on the support are studied by othorgonal testing method. The influence degree of every key factor on the support is suggested by range analysis. The support measures are refined by fuzzy theory and gray relative analysis method. The effect of support is verified by numerical analysis.The Numerical analysis on the distributions of stress in the wall rocks of the lane with thin coal roof provides logical proofs for the location of the return airway near goaf. The support measures are provided on this basis. The stress, displacement and failure zones in wall rocks of the different lanes are monitored in the field to evaluate the support effect of bolting with wire mesh. The distributions laws of stress, the displacement and the failure zones in wall rocks of lanes with different roofs are found. It is important to control the transformations of the lanes to make sure of the safty of the lanses.There are many new knowledges and research findings from the study on mining technologies of the the fully-mechanized coal mining with sub-level caving in high steep coal seams and support technologies in lanes with thin roofs. These findings will play a key role in practice and theory.更多还原