公路边坡被动柔性防护系统立柱性能的数值分析

发布时间：2018-04-26 15:51

本文选题：SNS柔性防护系统 + 普通钢柱　；参考：《重庆交通大学》2014年硕士论文

【摘要】：近几年来,一种全新的SNS柔性防护技术在国内水电站、矿山、铁路、公路等各种工程现场的崩塌落石防护中得到了越来越多的认可和应用。国内外至今，在边坡灾害事件中，频繁不断发生下列现象，即被动柔性防护系统在较大岩石冲击下，或较大量的塌方袭击钢绳网时，钢柱承受着巨大的外力而发生扭曲和弯曲变形，被动柔性系统有效高度大大降低，严重削弱了被动安全防护系统的防护能力。为此，必须更换钢柱，于是必然产生繁重的系统修复作业和较大费用的再开支。这种致命弱点的暴露，引起了各方面的关注。本文针对在边坡灾害事件中，公路边坡柔性防护系统中普通钢柱的变形破坏的特点，总结出钢柱变形的共同特征和原因，在此基础上，，提出了新的钢柱截面形式，即截面为中空方形与中空圆形的钢柱，在参考大量论文的前提下，通过ANSYS有限元分析的方法对三种钢柱进行了受力的对比分析，并进行了计算的验证。为了更好的对比分析出三种钢柱的性能差异，本文首先对三种钢柱进行了两种受弯模式下的性能对比分析；其次对三种钢柱进行了受扭性能的分析;最后针对钢柱的破坏模式，又进行了屈曲性能的对比分析。为了进行验证，每一种分析的后面还配有手算的过程。两种受弯模式的数据分析均表明，在相同的材料和外力作用下，普通钢柱的最大位移以及最大应力都要比中空方形与中空圆形钢柱的位移大得多；在自由扭转的情况下，普通钢柱截面的最大剪应力也要比中空方形钢柱与中空圆形钢柱大很多；另外，中空方形钢柱与中空圆形钢柱的第一屈曲模态的临界荷载则要比普通的工字钢的要大。总之，在相同的用料的情况下，中空方形钢柱与中空圆形钢柱在抗扭与抗弯曲的性能上比普通钢柱强，在抗屈曲性能上也要比普通钢柱好。以上得出的结论是建立在特定的受力模式情况下得出来的，由于问题的复杂性和其它原因，一些问题还有待深入研究。由于实体建模的复杂性和钢柱在SNS柔性防护系统中主要起支撑作用的事实，本文缺少对钢柱动力抗撞击性能的研究，重点对钢柱的力学性能进行了较为全面的分析，以及对钢柱进行了屈曲性能的分析。
[Abstract]:In recent years, a new SNS flexible protection technology has been more and more recognized and applied in domestic hydropower stations, mines, railways, highways and other projects in the field of rockfall protection. Up to now, the following phenomena occur frequently in slope disaster events at home and abroad, that is, passive flexible protection system under the impact of larger rock, or when a large number of landslides attack the steel rope network, The steel column is subjected to huge external force and is distorted and bent. The effective height of the passive flexible system is greatly reduced which seriously weakens the protection ability of the passive safety protection system. Therefore, the steel column must be replaced, which will inevitably result in heavy system repair operations and costly repayments. The exposure to this fatal weakness has attracted attention from all quarters. In view of the characteristics of deformation and failure of common steel columns in highway slope flexible protection system during slope disasters, the common characteristics and causes of steel column deformation are summarized in this paper. On this basis, a new steel column section form is proposed. The steel column with hollow square section and hollow circular section is compared and analyzed by ANSYS finite element analysis under the premise of referring to a large number of papers, and the calculation results are verified. In order to compare and analyze the performance difference of three kinds of steel columns better, this paper makes a comparative analysis of the performance of three kinds of steel columns under two bending modes; secondly, the torsional properties of three kinds of steel columns are analyzed; finally, aiming at the failure modes of steel columns, A comparative analysis of the buckling performance is also carried out. For verification, each analysis is followed by a manual process. The data analysis of the two bending modes shows that the maximum displacement and maximum stress of the ordinary steel column under the same material and external force are much larger than those of the hollow square and hollow circular steel columns, and in the case of free torsion, the maximum displacement and the maximum stress of the ordinary steel column are much larger than those of the hollow square and hollow circular steel columns. The maximum shear stress of common steel column section is much larger than that of hollow square steel column and hollow circular steel column, and the critical load of the first buckling mode of hollow square steel column and hollow circular steel column is larger than that of common I-steel column. In a word, the torsion and bending resistance of hollow square steel column and hollow circular steel column are better than that of ordinary steel column, and the buckling resistance of hollow square steel column is better than that of ordinary steel column. The above conclusions are based on the specific stress mode. Due to the complexity of the problem and other reasons, some problems need to be studied deeply. Due to the complexity of solid modeling and the fact that steel columns play a major supporting role in SNS flexible protection system, the dynamic impact resistance of steel columns is not studied in this paper, and the mechanical properties of steel columns are analyzed comprehensively. The buckling behavior of steel column is also analyzed.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U417.1

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