隧道掘进爆破合理微差时间研究

发布时间：2018-05-19 00:27

本文选题：隧道 + 微差爆破　；参考：《长沙理工大学》2014年硕士论文

【摘要】：微差爆破的效果与炮孔布置、围岩和地质条件等因素有关,而微差时间的选取更是微差爆破设计的核心所在。多年来,在隧道微差爆破设计中,合理延迟间隔的研究较少,微差时间的设计现状多是依靠工程经验选取,在隧道掘进工程中,往往会出现爆破效果不理想的情况。因此,如何考虑段间微差时间具有重要的意义。本文以和新隧道Ⅲ级围岩段爆破掘进工程为依托,综合运用理论分析、数值模拟两种方法进行研究。从岩石爆破破碎的作用机理出发,根据爆破爆破漏斗的形成物理过程给出了掏槽眼与下一圈起爆眼间合理延迟间隔时间计算的数学模型。研究结果认为：隧道掘进岩体中炸药起爆后物理过程主要包括爆轰阶段、破碎阶段、抛掷阶段。其中爆轰时间决定于炸药的爆速及装药长度；破碎阶段所需时间决定于岩体中裂隙的发展过程；抛掷阶段所需时间决定于破碎岩石的抛掷速度大小,而抛掷能的大小是决定抛掷速度的关键。最后计算得到适合本文工程的掏槽眼与下一圈起爆眼间合理微差时间为39.2ms-164ms。其次运用Midas/GTS数值模拟软件对隧道爆破掘进的振动影响进行数值分析。建模时不体现炮孔形状,采用将粉碎区边界上的荷载等效后施加于隧道开挖轮廓面来模拟爆破振动。着重对比分析了掏槽眼与第一、第二圈辅助眼之间五种不同微差时间的爆破方案下,隧道爆破开挖对围岩及隧道内结构物振速、应力的影响。计算结果表明：当微差时间选取75ms、100ms时,能有效降低围岩质点振动速度和初支结构的受拉破坏影响范围。
[Abstract]:The effect of millisecond blasting is related to the layout of blasting holes, surrounding rock and geological conditions, and the selection of millisecond time is the core of millisecond blasting design. In the design of tunnel millisecond blasting for many years, there is little research on reasonable delay interval. The present design situation of millisecond delay time is mostly based on engineering experience. In tunneling engineering, the blasting effect is often not satisfactory. Therefore, it is of great significance to consider the difference time between segments. In this paper, based on the blasting excavation project of the third grade surrounding rock section of the new tunnel, two methods of numerical simulation and theoretical analysis are used to carry out the research. Based on the mechanism of rock fragmentation and the physical process of blasting funnel formation, a mathematical model for calculating the reasonable delay interval between the cut hole and the next blasting hole is presented. The results show that the physical process of explosive detonation in tunneling rock mass mainly includes detonation stage, crushing stage and throwing stage. The detonation time is determined by the detonation velocity and charge length of the explosive, the time required in the crushing stage is determined by the development process of the cracks in the rock mass, and the time required in the throwing stage is determined by the throwing velocity of the broken rock. The magnitude of the throwing energy is the key to determining the throwing speed. Finally, the reasonable difference time between the cutting hole and the next ring detonation hole is 39.2 ms-164ms. Secondly, Midas/GTS numerical simulation software is used to analyze the vibration effect of blasting tunneling. The blasting vibration is simulated by applying the equivalent load on the boundary of the comminuted zone to the tunnel excavation contour. The effects of blasting excavation on the vibration velocity and stress of surrounding rock and structure in tunnel are analyzed in detail under five different millisecond time blasting schemes between cutting hole and first and second auxiliary hole. The calculated results show that the vibration velocity of surrounding rock particle and the range of tensile failure of the initial support structure can be effectively reduced when the differential time is 75 Ms or 100ms.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.6

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