城市高架桥爆破拆除及数值模拟研究

发布时间：2018-02-10 23:03

本文关键词： 爆破拆除高架桥分离式共节点模型 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】：近年来,随着爆破拆除方法在城市高架桥拆除工程中的成功应用,爆破拆除以其安全、经济、高效等优势,已成为了城市高架桥拆除的首选方法。然而,由于爆破拆除的相关理论研究滞后,致使爆破拆除事故时有发生,因此迫切需要对爆破拆除城市高架桥的相关理论等进行研究,以满足工程实际的需要。本文在前人有关爆破拆除的相关理论研究基础之上,对运用数值模拟的手段研究城市高架桥的爆破拆除进行了探讨。首先对采用有限元软件ANSYS/LS-DYNA建立分离式共节点模型时的材料模型、材料失效控制方式、接触方式及求解所用的控制参数等进行了研究。其次通过建立某城市高架桥桥墩的分离式共节点模型,研究了在不同的爆破高度下桥墩的倒塌过程,并从单元受力上分析了不同倒塌过程的原因,研究发现在切口顶部荷载一定的情况下,爆破高度越大,结构越容易失稳;同时发现在满足失稳倒塌的前提下不同爆高下桥墩倒塌的运动轨迹不同,且随着爆破高度的增加桥墩的倒塌运动一般也会变得更复杂些。最后建立了简支梁高架桥和连续梁高架桥的有限元模型,对在不同前后排桥墩爆破时间间隔下桥梁上部结构的塌落过程进行了研究,研究发现爆破时间间隔的取值是否合理将对上部结构的塌落过程和堆积形态等产生直接影响,所以应该引起高度的重视。通过以上研究表明,可采用分离式共节点模型对结构爆破拆除设计时的爆破参数选取等进行模拟并优化,这对在爆破拆除理论不完善下过分依赖经验的传统爆破拆除工程实际将起到突破作用,且将会在一定程度上推动爆破拆除理论的完善。
[Abstract]:In recent years, with the successful application of blasting demolition method in urban viaduct demolition, blasting demolition has become the preferred method for urban viaduct demolition with its advantages of safety, economy and efficiency. Due to the delay in the research of blasting demolition theory, the blasting demolition accidents occur from time to time. Therefore, it is urgent to study the relevant theories of blasting demolition of urban viaducts. In order to meet the needs of engineering practice, this paper is based on the previous relevant theoretical research on blasting demolition, The method of numerical simulation is used to study the demolition of urban viaduct by blasting. Firstly, the material model and material failure control method are discussed when the separated common node model is established by finite element software ANSYS/LS-DYNA. The contact mode and the control parameters used to solve the problem are studied. Secondly, the collapse process of the bridge pier under different blasting heights is studied by establishing the separated common node model of the bridge pier of a city viaduct. The causes of different collapse processes are analyzed from the point of stress of the element. It is found that the higher the blasting height is, the easier the structure is to lose stability when the load on the top of the notch is constant. At the same time, it is found that under the premise of unstable collapse, the trajectory of collapse of bridge pier under different explosion height is different. With the increase of blasting height, the collapse motion of pier will become more complicated. Finally, the finite element model of simply supported viaduct and continuous beam viaduct is established. In this paper, the collapse process of the superstructure of the bridge is studied under different blasting time intervals of front and rear piers. It is found that whether the blasting time interval is reasonable will have a direct effect on the collapse process and stacking shape of the superstructure. Therefore, high attention should be paid to it. Through the above research, it is shown that the split common node model can be used to simulate and optimize the blasting parameters in the design of structural blasting demolition. This will play a breakthrough role in the traditional blasting demolition engineering, which relies too much on experience under the imperfect blasting demolition theory, and will promote the perfection of blasting demolition theory to a certain extent.
【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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