深孔柱状装药爆破模型试验与数值模拟研究
发布时间：2018-08-18 11:50
【摘要】：随着浅部资源的耗尽,越来越多的煤矿进入深部开采。钻孔爆破在煤矿采掘中广泛应用,如巷道掘进爆破、厚硬顶板强制放顶、瓦斯增透等。其中,厚硬顶板强制放顶是在厚层坚硬岩石中进行深孔柱状装药爆破、没有自由面,其施工设计多以经验为主。而众多文献表明,在深部地层中岩层受高地应力作用,炸药爆炸作用范围与浅部地层不同。本文以此为背景,通过模型实验和数值模拟相结合的方法对冲击荷载作用下高地应力岩体的破坏形式及机理进行研究。通过查阅大量国内外文献,并结合应力波理论发现,高地应力场岩体爆破时在冲击荷载作用后会产生一个卸载波,并且随着地应力的增大而愈发明显;故认为在高地应力场岩体爆破,除了爆炸冲击波和爆生气体的直接作用,还包含卸载波在爆腔周围反射拉伸形成的裂隙。本文以此为基础,开展爆破模型试验,模拟冲击荷载作用后高地应力岩体在卸载波作用下的破坏损伤情况。模型实验采用抗压强度30MPa水泥砂浆材料模拟岩体、直径Φ400mm的钢管模拟岩体在深部的夹制作用,利用直径Φ5mm,长1000mm的铝纤维导爆索模拟柱状装药产生冲击波,以冲击波在钢管-水泥砂浆交界面处的反射模拟岩体中的卸载波。在炮孔周围布置应变片测点、采用超动态应变仪采集应变波,以分析炮孔周围应力场分布;同时预埋电极、借助并行电法进行爆破后模型体的损伤范围测试。采用LS-DYNA有限元软件,对约束条件下深孔柱状装药爆破破岩过程进行分析,研究约束条件下模型体中冲击波的传播历程和裂纹的扩展过程,以探究高应力场岩体深孔柱状装药裂隙扩展和损伤机理。主要得到以下结论:1)水泥砂浆中裂纹的萌生和扩展相较于应力波的传播有明显的滞后效应。2)通过钢套管约束作用下水泥砂浆的深孔爆破模型试验验证了爆炸卸载波在深部高地应力岩体中形成裂隙和损伤的可能性。3)根据爆破前后电阻率分布图,并结合数值模拟结果发现由卸载波形成的裂纹并不与爆破后的炮孔贯穿,其形成机理与爆生裂纹明显不同,炮孔周围的损伤是压碎和轴向拉伸形成的径向裂纹,而卸载波裂纹主要是因径向拉伸形成的轴向裂纹,且二者并不贯穿。4)以萨氏公式为基础,结合数值模拟中爆破振动峰值随爆心距变化的分布规律,拟合得到深孔爆破模型的爆破振动衰减的经验公式。5)根据混凝土、岩石等材料的应变率效应,并结合数值模拟中深孔爆破模型的应力波衰减规律,提出用于爆破工程现场的损伤破坏范围评估方法。
[Abstract]:With the depletion of shallow resources, more and more coal mines enter deep mining. Borehole blasting is widely used in coal mining, such as roadway excavation blasting, thick and hard roof forced roof release, gas penetration and so on. Among them, the thick hard roof forced caving is to carry on the deep hole cylindrical charge blasting in the thick layer hard rock, has no free surface, its construction design is mostly based on the experience. Many literatures show that the explosive explosion range is different from that in shallow strata because of the high ground stress in the deep strata. In this paper, the failure form and mechanism of high ground stress rock mass under impact load are studied by the combination of model experiment and numerical simulation. By consulting a large number of literatures at home and abroad and combining with the theory of stress wave, it is found that a unloading wave will be produced after rock mass blasting with high in-situ stress field under impact load, and it becomes more and more obvious with the increase of in-situ stress. Therefore, it is considered that in high stress field rock mass blasting, in addition to the direct action of blast shock wave and explosive gas, it also contains the crack formed by the reflection and tension of unloading wave around the explosion cavity. On this basis, the blasting model test is carried out to simulate the damage of high ground stress rock mass under unloading wave. In the model experiment, the compressive strength 30MPa cement mortar is used to simulate the rock mass, and the diameter 桅 400mm pipe is used to simulate the rock mass in the deep layer. The shock wave is produced by using the aluminum fiber detonating cable with diameter 桅 5 mm and long 1000mm to simulate the cylindrical charge. The unloading wave of rock mass is simulated by the reflection of shock wave at the interface between steel pipe and cement mortar. Strain gauge measurement points are arranged around the hole, strain waves are collected by super dynamic strain meter to analyze the distribution of stress field around the hole, and the damage range of the model body after blasting is measured with the help of the parallel electric method and the embedded electrode. LS-DYNA finite element software is used to analyze the rock breaking process of deep hole cylindrical charge blasting under constraint conditions, and the propagation history of shock wave and the crack propagation process in the model body under constraint conditions are studied. In order to explore the crack propagation and damage mechanism of deep hole cylindrical charge in high stress field rock mass. The main conclusions are as follows: (1) crack initiation and propagation in cement mortar have obvious hysteresis effect compared with stress wave propagation. 2) through the model test of deep hole blasting of cement mortar confined by steel casing, explosion unloading is verified. According to the distribution map of resistivity before and after blasting, the possibility of wave forming crack and damage in deep rock mass with high ground stress is 3. Combined with the numerical simulation results, it is found that the crack formed by unloading wave is not through the hole after blasting, and its formation mechanism is obviously different from that of explosion crack, and the damage around the hole is a radial crack formed by crushing and axial tension. However, the unloading wave crack is mainly caused by axial crack formed by radial tension, and both of them are not through 4. 4) on the basis of Saarde's formula, combined with the distribution law of the peak value of blasting vibration with the change of the distance between the blast center and the center of explosion in numerical simulation, According to the strain rate effect of concrete, rock and other materials, combined with the numerical simulation of the attenuation law of stress wave in the model of deep hole blasting, the empirical formula of attenuation of blasting vibration of deep hole blasting model is obtained by fitting. A method for evaluating the damage range of blasting engineering site is presented.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD235
本文编号：2189382
[Abstract]:With the depletion of shallow resources, more and more coal mines enter deep mining. Borehole blasting is widely used in coal mining, such as roadway excavation blasting, thick and hard roof forced roof release, gas penetration and so on. Among them, the thick hard roof forced caving is to carry on the deep hole cylindrical charge blasting in the thick layer hard rock, has no free surface, its construction design is mostly based on the experience. Many literatures show that the explosive explosion range is different from that in shallow strata because of the high ground stress in the deep strata. In this paper, the failure form and mechanism of high ground stress rock mass under impact load are studied by the combination of model experiment and numerical simulation. By consulting a large number of literatures at home and abroad and combining with the theory of stress wave, it is found that a unloading wave will be produced after rock mass blasting with high in-situ stress field under impact load, and it becomes more and more obvious with the increase of in-situ stress. Therefore, it is considered that in high stress field rock mass blasting, in addition to the direct action of blast shock wave and explosive gas, it also contains the crack formed by the reflection and tension of unloading wave around the explosion cavity. On this basis, the blasting model test is carried out to simulate the damage of high ground stress rock mass under unloading wave. In the model experiment, the compressive strength 30MPa cement mortar is used to simulate the rock mass, and the diameter 桅 400mm pipe is used to simulate the rock mass in the deep layer. The shock wave is produced by using the aluminum fiber detonating cable with diameter 桅 5 mm and long 1000mm to simulate the cylindrical charge. The unloading wave of rock mass is simulated by the reflection of shock wave at the interface between steel pipe and cement mortar. Strain gauge measurement points are arranged around the hole, strain waves are collected by super dynamic strain meter to analyze the distribution of stress field around the hole, and the damage range of the model body after blasting is measured with the help of the parallel electric method and the embedded electrode. LS-DYNA finite element software is used to analyze the rock breaking process of deep hole cylindrical charge blasting under constraint conditions, and the propagation history of shock wave and the crack propagation process in the model body under constraint conditions are studied. In order to explore the crack propagation and damage mechanism of deep hole cylindrical charge in high stress field rock mass. The main conclusions are as follows: (1) crack initiation and propagation in cement mortar have obvious hysteresis effect compared with stress wave propagation. 2) through the model test of deep hole blasting of cement mortar confined by steel casing, explosion unloading is verified. According to the distribution map of resistivity before and after blasting, the possibility of wave forming crack and damage in deep rock mass with high ground stress is 3. Combined with the numerical simulation results, it is found that the crack formed by unloading wave is not through the hole after blasting, and its formation mechanism is obviously different from that of explosion crack, and the damage around the hole is a radial crack formed by crushing and axial tension. However, the unloading wave crack is mainly caused by axial crack formed by radial tension, and both of them are not through 4. 4) on the basis of Saarde's formula, combined with the distribution law of the peak value of blasting vibration with the change of the distance between the blast center and the center of explosion in numerical simulation, According to the strain rate effect of concrete, rock and other materials, combined with the numerical simulation of the attenuation law of stress wave in the model of deep hole blasting, the empirical formula of attenuation of blasting vibration of deep hole blasting model is obtained by fitting. A method for evaluating the damage range of blasting engineering site is presented.
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD235
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1 徐轩;深孔柱状装药爆破模型试验与数值模拟研究[D];安徽理工大学;2017年
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