桥梁控制爆破拆除的数值模拟与爆破方案优化

发布时间：2018-02-11 14:44

本文关键词： 桥梁拆除控制爆破数值模拟高墩拱桥 ANSYS/LS-DYNA　出处：《长安大学》2015年硕士论文　论文类型：学位论文

【摘要】：目前,我国公路交通基础建设势头趋于缓和,在桥梁工程市场,改扩建项目的市场份额稳步增长,拆除工程也逐渐成为新兴的热点行业。然而,当前最常用的控制爆破拆除技术,其规范仍处于定性设计的范畴,理论研究落后于工程实践,爆破事故时有发生,限制了此技术的发展。若能借助日新月异的计算机数值模拟技术,实现桥梁爆破倒塌全过程的可视化预测,则可摆脱对规范中经验公式的过分依赖,提出更有针对性的爆破设计优化方案和施工安全防护方案,完成爆破拆除工程从“粗放”到“精细”的跨越。为此,本文主要研究了如下内容:首先,综述了桥梁爆破拆除中常用的技术手段,归纳出了桥梁倒塌破坏的基本模式,据此建立简化的力学模型,分析了影响爆破缺口参数的主要因素。其次,提出了以LS-DYNA求解器为核心的多软件联合建模求解法,以高效求解桥梁倒塌这一复杂显式动力问题。再次,根据倒塌过程中材料的力学行为,探讨了合适的单元类型和材料模型的选择,确定了控制材料失效、接触碰撞、计算方法等的一系列参数。接着,利用上述方法,成功模拟了桥梁爆破拆除中两个最具代表性的工程实例——倒向空间受限高墩的定向爆破拆除和拱桥多段延时起爆、一次性坍塌拆除。最后,根据模拟出的动态倒塌结果,评价了初拟爆破方案中切口参数、起爆顺序及延时间隔的合理性,并提出了相应的缺口优化方案和施工安全防护措施。研究结果表明,桥梁爆破坍塌全过程的数值模拟结果符合预期,可多角度、分部件地观察倒塌姿态、爆碴块度大小及爆堆形态,实现了爆破效果的可视化预测,推动了爆破技术的创新和精进,对桥梁爆破拆除工程的实施具有指导意义。
[Abstract]:At present, the momentum of highway traffic infrastructure in China tends to ease. In the bridge engineering market, the market share of reconstruction and expansion projects has steadily increased, and demolition projects have gradually become a new hot industry. At present, the most commonly used controlled blasting demolition technology is still in the category of qualitative design, the theoretical research falls behind the engineering practice, and blasting accidents occur from time to time. The development of this technology is limited. If the rapid development of computer numerical simulation technology can be used to realize the visual prediction of the whole process of bridge blasting collapse, the over-reliance on empirical formulas in the code can be avoided. A more targeted blasting design optimization scheme and construction safety protection scheme are proposed to complete the leapfrogging of blasting demolition from "extensive" to "fine". Therefore, the main contents of this paper are as follows: first, This paper summarizes the technical methods used in blasting demolition of bridges, sums up the basic modes of collapse and failure of bridges, establishes a simplified mechanical model, and analyzes the main factors affecting the parameters of blasting notches. A multi-software joint modeling method with LS-DYNA solver as the core is proposed to solve the complex explicit dynamic problem of bridge collapse efficiently. Thirdly, according to the mechanical behavior of the material during the collapse process, The selection of appropriate element type and material model is discussed, and a series of parameters for controlling material failure, contact collision and calculation method are determined. This paper successfully simulates the demolition of two most representative engineering examples in the blasting demolition of bridges-directional blasting demolition of high piers with backward space constraints, delayed blasting demolition of arch bridges in multiple sections and one-off collapse demolition. Finally, according to the simulated dynamic collapse results, The rationality of notch parameters, initiation sequence and delay interval in the initial blasting scheme is evaluated, and the corresponding notch optimization scheme and construction safety protection measures are put forward. The numerical simulation results of the whole process of bridge blasting collapse are in line with the expectation. The collapse attitude, the size of blasting debris and the shape of blasting pile can be observed from different angles. The visual prediction of blasting effect is realized, and the innovation and refinement of blasting technology are promoted. It is of guiding significance to the implementation of bridge blasting demolition project.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U445.6

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