煤岩组合体动力破坏规律实验研究

发布时间：2018-09-01 13:37

【摘要】：冲击地压威胁着煤矿的安全和高效生产。随着开采深度的增加、开采强度不断加大以及开采条件越来越复杂,我国煤矿发生冲击地压的现象越来越多,危害越来越大,必须及早引起重视。冲击地压是煤岩地层受采动影响而发生的动力灾害现象,是煤岩体在外部应力作用下快速破裂的结果,是典型的能量突然释放与能量耗散过程。冲击地压一定是在能量突然释放的驱使下发生的,既然如此,引发冲击地压的能量到底积聚在哪儿?对于这些积聚的能量,能否在释放速度和强度上予以人为控制,以此来避免发生冲击地压呢?基于上述问题,本论文从能量积聚和释放的角度出发,开展组合岩体动力破坏规律实验研究,目的是确定能量积聚的具体层位,从理论上提出减缓能量释放的有效措施,从而为有针对性的防治冲击地压提供支撑。对煤岩体及组合体冲击破坏过程及能量转化规律进行理论分析,结果表明,受岩石内部裂纹及空隙不同的影响,其能量积聚能力的大小及能量耗散的方式有很大差别,材料强度、材料均质度及能量输入率决定了煤样能量耗散的方式;组合体煤岩在冲击破坏过程中,内部岩石之间相互作用,不断的进行能量的传递与整体的平衡自组织,其中一部分岩层对组合体的能量积聚量及能量耗散特征起主要作用。对峻德矿17煤层的煤、细砂岩和粗砂岩单体进行变形破坏实验,分析对比煤岩单体的全过程应力应变曲线,结果表明煤峰前积聚能量较低,发生破坏时消耗能量少,具有强冲击倾向性,粗砂岩和细砂岩峰前积聚能量比煤高得多,能发生瞬间破坏,将能量大量释放,具有中等冲击倾向性。岩石的强度越大,极限储能越大,脆性越强,弹性能释放的越彻底。将细砂岩、粗砂岩和煤三种岩石按照设计要求进行组合,对比分析组合试件各组分的能量储存情况,实验结果表明在软硬不同的组合煤岩层中,弹性模量大的坚硬岩块,虽不易发生变形,但储能较小,不易积聚能量。而弹性模量较小的软弱岩层,在能量储存上更占优势,更容易积聚能量,在发生整体冲击地压时,起主导作用。组合煤岩体中的能量主要积聚在软弱岩层中,软弱岩层是能量积聚的关键层。组合体中硬度差别越大,冲击效应越强。研究成果有助于更加深入的从能量积聚角度解释冲击地压发生的本质,对组合岩体内的能量分布有了较深的认识,对现场有针对性的防治冲击地压问题具有重大的理论意义。
[Abstract]:Rock burst threatens the safety and efficiency of coal mine production. With the increase of mining depth, the mining intensity is increasing and the mining conditions are becoming more and more complicated. The phenomenon of rock burst in coal mines in our country is more and more, and the harm is becoming more and more serious. Therefore, attention must be paid to it as soon as possible. Rock burst is a dynamic disaster phenomenon of coal and rock strata affected by mining. It is the result of rapid rupture of coal and rock mass under the action of external stress. It is a typical process of sudden energy release and energy dissipation. Shock ground pressure must have been driven by the sudden release of energy. In that case, where does the energy that triggers the impact pressure accumulate? Can these accumulated energies be artificially controlled in terms of release speed and intensity to avoid shock ground pressure? Based on the above problems, this paper, from the angle of energy accumulation and release, carries out an experimental study on the dynamic failure law of composite rock mass, the purpose of which is to determine the specific horizon of energy accumulation and to put forward effective measures to slow down the energy release theoretically. So as to provide support for the prevention and treatment of shock ground pressure. The impact failure process and energy transformation law of coal, rock mass and assemblage are theoretically analyzed. The results show that the magnitude of energy accumulation ability and the energy dissipation mode are very different due to different cracks and voids in rock. Material strength, material homogeneity and energy input rate determine the energy dissipation mode of coal sample. Some of them play an important role in energy accumulation and energy dissipation characteristics of the assemblage. The deformation and failure experiments of coal, fine sandstone and coarse sandstone in 17 coal seam in Junde Mine were carried out, and the stress-strain curves of coal and rock monomers were analyzed and compared. The results show that the accumulated energy before coal peak is lower, and the energy consumption is less when failure occurs. It has strong impact tendency. The accumulation of energy in front of coarse sandstone and fine sand rock is much higher than that of coal. The greater the strength of rock, the greater the limit energy storage, the stronger the brittleness and the more thoroughly the elastic energy is released. Three kinds of rocks, fine sandstone, coarse sandstone and coal, are combined according to the design requirements, and the energy storage of each component of the combination specimen is compared and analyzed. The experimental results show that in the soft and hard coal and rock combination, the hard rock with high elastic modulus is the hard rock. Although it is not easy to deform, the energy storage is small and it is difficult to accumulate energy. The weak rock with lower elastic modulus has more advantages in energy storage and accumulates energy more easily, which plays a leading role when the whole rock burst occurs. The energy in the combined coal and rock mass is mainly accumulated in the weak rock stratum, which is the key layer of the energy accumulation. The greater the hardness difference in the combination, the stronger the impact effect. The research results are helpful to explain the nature of rock burst from the perspective of energy accumulation, to understand the energy distribution in the assemblage rock, and to have great theoretical significance for the prevention and treatment of shock ground pressure in the field.
【学位授予单位】：黑龙江科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TD324

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