爆破振动作用下隧道洞口段结构的动力响应研究

发布时间：2018-04-12 17:11

本文选题：隧道洞口 + 爆破振动　；参考：《中国地质大学》2017年博士论文

【摘要】：隧道洞口段是隧道施工中易发生安全事故的场所,矿山法施工时产生的不当爆破振动会诱发隧道洞口的过大变形、边坡失稳、甚至洞口坍塌等灾害。隧道洞口的安全性问题一直是隧道工程中重点关注的焦点。开展隧道洞口在爆破振动作用下的动力响应研究,分析影响洞口安全稳定的主要因素,研究洞口爆破施工产生的振动对隧道洞口段围岩、支护结构、边坡的安全稳定性的影响规律,具有重要的理论和工程实践意义。目前的相关研究中,隧道洞口结构的安全性主要通过获取质点振动峰值速度的大小来判断。在这一判断过程中,对隧道洞口结构振动的理论分析多限于静态分析,对隧道洞口段自身特点下的爆破振动规律研究不足,对隧道洞口围岩、结构、边坡等结构在振动作用下的动态分析研究不足。鉴于此,本文从柱状药包爆破下的振动场分析出发,采用理论分析、现场试验监测、数值计算等方法对隧道洞口段围岩、支护结构和洞口边坡在隧道洞口爆破施工引起的振动作用下的动力响应进行了分析和研究。对国内外有关隧道洞口结构在振动作用下的研究内容和研究方法进行了归纳分析,指出了目前相关研究的不足以及今后的发展趋势,在此基础上提出了本文的研究概况。对隧道洞口段的力学特征进行了全面的分析,在对常见隧道洞口破坏形式的总结基础上分析了影响隧道洞口安全稳定的基本因素。系统分析了柱状药包爆破下的振动在理想弹性介质中的传播规律,获得了振动传播下的位移和应力计算公式,并据此分析了隧道洞口围岩、支护结构和洞口边坡的爆破振动传播特征。依据能量耗散原理研究了介质微观缺陷对振动传播的影响,提出了单位面积耗散能密度的概念,并据此对隧道洞口爆破振动规律进行修正,推导出隧道洞口耗散能密度与爆破振动速度场的计算公式。运用耗散能密度原理对隧道洞口多次爆破振动作用下介质的累计损伤问题进行研究,得到了由爆破振动耗散能量计算隧道洞口段介质累计损伤的方法。研究计算了隧道洞口段围岩和支护结构在爆破振动下的动态应力。研究并获得了隧道洞口埋深、边坡倾角、隧道进深等洞口参数对隧道洞口段无支护段围岩的振动动态极值应力响应的规律。根据能量耗散原理提出了隧道洞口段无支护段围岩的动态安全判定依据并讨论了隧道洞口段支护结构的安全性。针对隧道洞口边坡的结构特性,建立了隧道洞口边坡振动模型并进行了动力响应分析,推导了隧道洞口边坡动态稳定安全系数的计算公式。通过实例计算分析了隧道洞口边坡动态安全系数与隧道进深和爆破药量的关系,结果表明洞口边坡的动态稳定安全系数与爆破振动的强度、入射角度、频率、持续时间、距离以及隧道洞口参数等因素有关。
[Abstract]:Tunnel opening section is prone to safety accidents in tunnel construction. Improper blasting vibration produced during mine construction will induce excessive deformation of tunnel opening, slope instability, and even collapse of tunnel entrance and so on.The safety of tunnel entrance has always been the focus of attention in tunnel engineering.The dynamic response of tunnel opening under blasting vibration is studied, and the main factors affecting safety and stability of tunnel entrance are analyzed.The influence law of slope safety and stability has important theoretical and engineering significance.At present, the safety of tunnel entrance structure is mainly determined by obtaining the peak velocity of particle vibration.In this judgment process, the theoretical analysis of structural vibration of tunnel entrance is mostly confined to static analysis, and the study of blasting vibration law under the characteristics of tunnel entrance section is insufficient, and the surrounding rock and structure of tunnel entrance are also studied.The dynamic analysis of slope and other structures under the action of vibration is not enough.In view of this, starting from the vibration field analysis of cylindrical charge blasting, this paper uses the methods of theoretical analysis, field test monitoring and numerical calculation to analyze the surrounding rock of tunnel entrance.The dynamic response of the supporting structure and the slope under the vibration caused by blasting at the tunnel entrance is analyzed and studied.This paper summarizes and analyzes the research contents and research methods of tunnel entrance structure under the action of vibration at home and abroad, and points out the deficiency of relevant research at present and the development trend in the future. On this basis, the general situation of this paper is put forward.The mechanical characteristics of tunnel entrance are analyzed comprehensively, and the basic factors influencing the safety and stability of tunnel entrance are analyzed on the basis of summing up the common failure forms of tunnel entrance.The propagation law of vibration in ideal elastic medium under cylindrical charge blasting is analyzed systematically, the displacement and stress calculation formulas under vibration propagation are obtained, and the surrounding rock of tunnel entrance is analyzed accordingly.The characteristics of blasting vibration propagation of supporting structure and slope at the hole.According to the principle of energy dissipation, the effect of medium microdefects on vibration propagation is studied, the concept of dissipation energy density per unit area is proposed, and the vibration law of tunnel entrance blasting is modified accordingly.The formulas of energy dissipation density and velocity field of blasting vibration at tunnel entrance are derived.The accumulative damage of the medium under the action of multiple blasting vibration at the tunnel entrance is studied by using the principle of dissipative energy density, and the method of calculating the cumulative damage of the medium in the tunnel opening by blasting vibration dissipation energy is obtained.The dynamic stress of surrounding rock and supporting structure in tunnel opening under blasting vibration is studied and calculated.The response of tunnel entrance depth slope inclination and tunnel depth to the vibration dynamic extreme stress of surrounding rock without supporting section is studied and obtained.Based on the principle of energy dissipation, the dynamic safety determination of surrounding rock in unsupported section of tunnel entrance is proposed and the safety of supporting structure in tunnel entrance is discussed.According to the structural characteristics of tunnel entrance slope, the vibration model of tunnel entrance slope is established, and the dynamic response analysis is carried out, and the formula for calculating the safety factor of tunnel entrance slope dynamic stability is derived.The relationship between dynamic safety factor of tunnel entrance slope and tunnel depth and blasting charge is calculated and analyzed by an example. The results show that the dynamic stability safety factor of tunnel entrance slope is related to the intensity of blasting vibration, incident angle, frequency, duration, etc.Distance and tunnel entrance parameters are related.
【学位授予单位】：中国地质大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：U455;U451

【相似文献】