露井联采台阶爆破对地下巷道稳定性影响研究

发布时间：2018-05-04 01:04

本文选题：露井联采 + 台阶爆破　；参考：《北京科技大学》2015年博士论文

【摘要】：露井联合开采条件下,两种开采方法的采动影响域的相互重叠表现为一种采动效应对另一个平衡体系的干扰或作用,使得两种开挖体系之间相互诱发或相互制约,从而组成一个复合动态变化系统。由于井工与露天矿之间的特殊布置关系,导致露天与井工复合采动巷道稳定性问题较为复杂。在已采露天边坡下布置的采区大巷的围岩中形成由露天台阶爆破和地下开采相互影响的应力场,巷道围岩将在两种采动域相互重叠或包含的过程中,产生两种开挖体系的相互诱发与扰动响应,使围岩的应力场、变形场与破坏场等多次叠加、调整和分布,致使围岩的强度多次被损伤、弱化,此外,露天开采使大巷垂直应力减少,开采产生的卸荷应力使大巷围岩稳定变得十分敏感,导致井工回采影响对大巷围岩的稳定影响较一般大巷明显,由此造成巷道围岩失稳的概率逐渐增大。虽然采用露井联合开采取得了很好的绩效,但生产过程中也遇到了种种挑战。在安家岭露天矿采掘过程中,借助了大量的台阶爆破进行开挖,而爆破所产生的地震波相当于给巷道围岩增加了一种具有致滑作用和井工矿煤岩层的动态荷载。依托安家岭煤矿露井联采为背景,基于现有的爆破波动理论,重点开展了爆破振动下的巷道稳定性研究,探寻爆破振动对既有巷道的影响机理,并通过数值模拟,开展地震波对巷道围岩松动圈、既有衬砌和锚杆造成的受力位移分析计算,最终以现场收集到的实际数据验证分析理论计算,得出了露井联采台阶爆破振动对既有巷道的影响规律。主要研究工作与重要结论如下： 1、明确地提出了爆破振动的积累效应是爆破振动引起巷道围岩失效的基本原因。用爆破振动积累效应的突发特性和存储特性解释了巷道围岩失稳机理,阐明了问题的本质。 2、量化了相隔时间为τ的爆破振动关联程度,得到了两次爆破振动关联程度与其对围岩破坏作用的关系,这一关系揭露了爆破载荷诱发巷道围岩失稳的关键。 3、通过小波包频带能量分析法分析了爆破震动累积效应对围岩物理力学性能的弱化作用,发现了爆破振动信号主频向低频发展呈多频带多振型特点。 4、边坡岩体的剥离引起巷道围岩应力释放,围岩最大拉应力增大且其改变幅度与剥离岩体的重量及其相对巷道的位置有很大关系。 5、指出了爆破震动累积效应的起因、作用过程以及作用结果。关联函数Rz反应了相隔时间为τ的爆破振动关联程度,表明了爆破振动累积效应的起因；小波分析表明爆破振动往低频发展呈多频带多振型的特点,揭示了爆破振动累积效应的作用过程以及表现特征；利用PFC验证了爆破振动引起围岩损伤的发展累积过程,指出了爆破振动累积效应的作用结果。 6、爆破振动的累积效应对巷道稳定性的影响作用不可忽视,爆破方案设计及爆破作业时应重视爆破累积效应。
[Abstract]:Under the condition of combined open-hole mining, the overlap of the two mining influence areas is the interference or action of one kind of mining effect on the other equilibrium system, which makes the two excavation systems induce or restrict each other. Thus, a composite dynamic change system is formed. Because of the special arrangement relationship between the workmen and the opencast mine, the stability of the roadway is complicated. In the surrounding rock of the roadway of the mining area arranged under the mined open-pit slope, the stress field affected by the open-pit bench blasting and underground mining is formed, and the surrounding rock of the roadway will overlap or contain in the two mining fields. In addition, the stress field, deformation field and failure field of surrounding rock are superimposed, adjusted and distributed many times so that the strength of surrounding rock is damaged and weakened many times. The vertical stress of roadway is reduced by open-pit mining, and the unloading stress caused by mining makes the stability of surrounding rock of roadway very sensitive, which leads to the influence of mining work on the stability of surrounding rock of roadway is more obvious than that of general roadway. As a result, the probability of surrounding rock instability increases gradually. Although the use of open-hole mining has achieved good performance, but the production process has encountered a variety of challenges. In the mining process of Anjialing open-pit mine, a large number of bench blasting is used to excavate, and the seismic wave produced by blasting is equivalent to adding a kind of dynamic load to the surrounding rock of roadway and coal and rock strata of well and mine. Based on the existing theory of blasting wave, the stability of roadway under blasting vibration is studied, and the influence mechanism of blasting vibration on existing roadway is explored, and the numerical simulation is carried out. The stress displacement caused by both lining and bolt is analyzed and calculated by seismic wave to loose circle of roadway surrounding rock. Finally, the theoretical calculation is verified by the actual data collected on the spot. The influence of bench blasting vibration on the existing roadway is obtained. The main research work and important conclusions are as follows: 1. The accumulative effect of blasting vibration is the basic reason for failure of surrounding rock of roadway caused by blasting vibration. The mechanism of surrounding rock instability of roadway is explained by the burst characteristic and storage characteristic of blasting vibration accumulation effect, and the essence of the problem is clarified. 2. The correlation degree of blasting vibration with interval 蟿 is quantified, and the relation between the correlation degree of twice blasting vibration and the failure of surrounding rock is obtained, which reveals the key of rock instability induced by blasting load. 3. The weakening effect of blasting vibration cumulative effect on the physical and mechanical properties of surrounding rock is analyzed by using wavelet packet band energy analysis method. It is found that the main frequency of blasting vibration signal develops to low frequency frequency with multi-band and multi-mode characteristics. 4. The exfoliation of slope rock mass causes the stress release of roadway surrounding rock, and the maximum tensile stress of surrounding rock increases and its change range is related to the weight of the rock mass and its relative position to the roadway. 5. The cause, process and result of the cumulative effect of blasting vibration are pointed out. The correlation function Rz reflects the correlation degree of blasting vibration with interval 蟿, which indicates the cause of the cumulative effect of blasting vibration, and wavelet analysis shows that the evolution of blasting vibration to low frequency has the characteristics of multi-band and multi-mode. The action process and performance characteristics of blasting vibration accumulation effect are revealed, and the development and accumulation process of surrounding rock damage caused by blasting vibration is verified by PFC, and the result of blasting vibration accumulation effect is pointed out. 6. The cumulative effect of blasting vibration on the stability of roadway can not be ignored. The blasting plan design and blasting operation should pay attention to the cumulative blasting effect.
【学位授予单位】：北京科技大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TD353

【参考文献】