基于不同爆破致裂方式的液态二氧化碳相变增透应用研究

发布时间：2018-02-02 22:55

本文关键词： 液态二氧化碳相变爆破数值模拟不同起爆条件应用研究　出处：《中国矿业大学》2015年硕士论文　论文类型：学位论文

【摘要】：对于单一低渗透性煤层,除采取水力化技术和深孔预裂爆破措施进行煤层增透外,近年来又发展了一种液态二氧化碳相变爆破增透技术,作为一种新型的煤层增透技术,该技术具有爆破不产生火花、压力可控、易于储存和运输和安全性高等诸多优点。本文首先对二氧化碳液相、气相物理性质进行了阐述,通过分析液态二氧化碳爆破过程热力学变化,分析了二氧化碳由液态转化为气态的能量转变过程,研究了液态二氧化碳转变为气态的热力学计算公式,并给出了部分压力、温度下气化潜热和膨胀功,根据TNT当量模型计算了试验所用储液管TNT当量。其次,结合爆破理论,分析了高压二氧化碳气体在煤体致裂的作用过程及应力波传播规律,根据损伤断裂力学理论计算了致裂应力波形成的初始宏观裂纹尖端的有效应力强度因子,分析了致裂产生的高压二氧化碳气体作用下裂纹的扩展过程,并研究了裂缝动态延伸规律。利用有限元分析软件ANSYS_LS_DYNA3D,以断裂力学理论为基础,建立了液态二氧化碳爆破致裂作用计算模型,对液态二氧化碳在煤体中爆破产生的应力场进行数值模拟;通过研究爆破后煤体中应力波的传播规律,分析了煤体内的应力波及裂纹扩展情况,研究了不同当量作用下煤体裂隙发育及影响范围。在总结理论研究和数值模拟的基础上,确定了五种不同的液态二氧化碳爆破增透方案,通过在潞安集团常村煤矿3#煤层进行试验,分析了该爆破增透技术的效果。经液态二氧化碳相变爆破增透后,瓦斯抽采量提高1.4~3.5倍,平均提高2.5倍,爆破增透效果显著。不同爆破增透方案对提高瓦斯抽采效果也有一定的区别,从抽采纯量上可以看出,采用二次爆破或延迟爆破增透方案对于提高瓦斯抽采效果有更为明显的作用。
[Abstract]:For a single low permeability coal seam, a liquid CO2 phase change blasting antireflection technology has been developed in recent years, in addition to taking hydraulic technology and deep-hole pre-splitting blasting measures for coal seam antireflection. As a new type of coal seam antireflection technology, this technology has many advantages, such as no sparks produced by blasting, controllable pressure, easy storage and transportation, high safety and so on. The physical properties of the gas phase are described. By analyzing the thermodynamic changes in the explosion process of liquid carbon dioxide, the energy transformation process of carbon dioxide from liquid to gaseous state is analyzed. The thermodynamic calculation formula for the conversion of liquid carbon dioxide to gaseous state is studied, and the latent heat of gasification and expansion work at partial pressure and temperature are given. According to the TNT equivalent model, the TNT equivalent of the liquid storage pipe used in the test is calculated. Secondly, combined with the blasting theory, the action process and stress wave propagation of high-pressure carbon dioxide gas in coal body are analyzed. According to the theory of damage fracture mechanics, the effective stress intensity factor of the initial macroscopic crack tip formed by crack stress wave is calculated, and the crack propagation process under the action of high pressure carbon dioxide gas produced by crack is analyzed. Based on the theory of fracture mechanics, the calculation model of crack induced by liquid carbon dioxide blasting is established by using the finite element analysis software ANSYSS-DYNA3D. The stress field caused by liquid carbon dioxide blasting in coal is numerically simulated. By studying the propagation law of stress wave in coal body after blasting, the stress and crack propagation in coal body is analyzed. On the basis of summarizing the theoretical research and numerical simulation, five kinds of liquid carbon dioxide blasting antireflection schemes are determined. Based on the tests in the coal seam of Changcun Coal Mine of Lu'an Group, the effect of the blasting antireflection technique is analyzed. After the liquid carbon dioxide phase change blasting, the gas drainage volume is increased by 1.4 ~ 3.5 times. The average increase is 2.5 times, and the effect of blasting antireflection is remarkable. Different blasting antipenetration schemes have some differences in improving the gas drainage effect, which can be seen from the extraction scalar quantity. It is more obvious to improve the effect of gas drainage by using the antidimosis scheme of secondary blasting or delayed blasting.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TD712.6

【参考文献】