第35卷第6期岩石力学与工程学报V ol.35 No.6 2016年6月Chinese Journal of Rock Mechanics and Engineering June，2016被动柔性防护网中减压环力学试验及有限元分析刘成清1，2，陈林雅1，陈驰3，邓永祥1(1. 西南交通大学土木工程学院，四川成都 610031；2. 西南交通大学高速铁路线路工程教育部重点实验室，四川成都 610031；3. 中铁第四勘察设计院集团有限公司，湖北武汉 430063)摘要：为研究被动柔性防护网中减压环力学模型和耗能计算公式，首先，分析减压环的作用机制，得到其受力性能的主要影响因素为：预紧力、铝套筒长度、钢管壁厚和钢管环径；接着，进行减压环力学试验及有限元分析，验证结果与试验结果吻合较好；然后，进一步研究主要影响因素下减压环的荷载–位移曲线及其耗能特点，并结合工程实例，对比分析有减压环和无减压环时被动柔性防护网在落石冲击下的动力响应。
研究结果表明：(1) 减压环启动荷载随铝套筒长度的增大或钢管环径的减小而增加。
其耗能在一定范围的铝套筒长度下变化较显著，而钢管环径对耗能的影响不大；(2) 减压环启动荷载及耗能随着预紧力或钢管壁厚的增大而增加；(3) 减压环的荷载–位移曲线满足三阶段变化规律，提出的三折线分析模型能够很好地反映减压环荷载–位移曲线特点，给出的耗能计算公式便于减压环的设计及工程应用；(4) 减压环能使被动柔性防护网的柔性增强，冲击作用时间延长，并能降低与减压环连接的拉锚绳、支撑绳等构件的耗能。
关键词：数值模拟；被动柔性防护网；减压环；力学试验；荷载–位移曲线中图分类号：O 242 文献标识码：A 文章编号：1000–6915(2016)06–1245–10Full scale test and FEM simulation to ring-type brake energydissipater in falling rock protectionLIU Chengqing1，2，CHEN Linya1，CHEN Chi3，DENG Yongxiang1(1. School of Civil Engineering，Southwest Jiaotong University，Chengdu，Sichuan 610031，China；2. Key Laboratory of High-speed Railway Engineering，Ministry of Education，Southwest Jiaotong University，Chengdu，Sichuan 610031，China；3. China Railway Siyuan Survey and Design Group Co.，Ltd.，Wuhan，Hubei 430063，China)Abstract：The energy dissipater of ring-type brake for falling rock protection was studied to investigate the load-displacement curves and the energy dissipation formula. Firstly，the working mechanism of the energy dissipater of ring-type brake was described. The main factors of influence，such as the pretension，the length of aluminum sleeves，the thickness of the steel pipe and the diameter of steel pipe were obtained. Secondly，the full-scale tests and finite element analysis for verification were carried out and the results were in good agreement with each other. Thirdly，the load-displacement curves and the energy dissipation characteristics under the action of the main influence factors were further studied based on the finite element simulation of the engineering examples. The starting force of the energy dissipater of ring-type brake was found to increase with the increasing of the收稿日期：2015–06–16；修回日期：2015–07–23基金项目：国家自然科学基金资助项目(51278428，51308471)；中央高校基本科研业务费专项资金资助项目(2682014CX066)S upported by the National Natural Science Foundation of China(Grants Nos. 51278428 and 51308471) and Fundamental Research Funds for the Central Universities(Grant No. 2682014CX066)作者简介：刘成清(1976–)，男，2009年于同济大学结构工程专业获博士学位，现任副教授，主要从事工程抗震及抗冲击方面的教学与研究工作。
E-mail：lcqjd@DOI：10.13722/ki.jrme.2015.0776• 1246 • 岩石力学与工程学报 2016年length of the aluminum sleeves and the decreasing of the diameter of steel pipe. The energy dissipation changed significantly with the length of the aluminum sleeves in a certain range ，while the diameter of steel pipe had a little effect on its energy dissipation. The staring force and energy dissipation of the energy dissipater of ring-type brake were increased gradually with the increasing of pretension or thickness of the steel pipe. The proposed tri-linear analysis model reflected well the characteristic of the load-displacement curves with three stages and the presented energy dissipation formula facilitated the design and engineering application of the energy dissipater of ring-type brake. The energy dissipater of ring-type brake enhanced the flexibility of the passive flexible protection and prolong the impacting time ，also reduced significantly the energy consumption of the tension anchor rope and the supporting rope.Key words ：numerical simulation ；falling rock protection ；ring-type brake energy dissipater ；full-scale testing ；load-displacement curve1 引 言被动柔性防护网是由金属柔性网、拉锚系统、消能件和钢柱4部分构成的柔性防护系统技术和产品[1-3]，如图1所示。
由于它易于安装和维护，其柔性和强度足以吸收、分散和传递落石能量而系统损伤小[4-6]，应用越来越广泛。
由钢管、铝套筒及钢丝绳组成的减压环作为整体结构中重要的耗能件，如图2所示，其力学性能及耗能性能亟待研究。
(a)(b)图1 被动柔性防护系统的组成Fig.1Composition of the passive flexible protection(a)(b)图2 减压环结构图Fig.2 Structure of the energy dissipater of ring-type brake目前，D. Peila 等[7]进行了被动柔性防护网结构落石冲击试验和弹簧型消能件的力学试验，研究了结构整体受力性能，分析了受力薄弱部位，对研究减压环的力学性能有借鉴意义；G . Gottardi 和L. Govoni [8]通过结构整体的落石冲击试验，获得了冲击力峰值与落石质量、速度等的关系，但没有研究消能件的力学性能及其对结构整体受力的影响；C. Gentilini 等[9]通过数值模拟研究了被动柔性防护网的受力性能，并将分析结果用于防护结构设计，侧重于结构整体分析，消能件采用的本构关系不利于广泛应用；J. J. Del Coz Díaza 等[10]利用有限元分析和试验对比，研究了减压环的非线性力学行为，进行了有限元原理及编程分析；由于未给出适当的参钢丝绳铝套筒钢管第35卷第6期刘成清等：被动柔性防护网中减压环力学试验及有限元分析 • 1247 •数建议，不便于减压环的设计和工程应用。
在国内，刘成清等[11]对被动柔性防护网结构进行了落石冲击试验，研究了防护结构整体变形和关键构件耗能及其破坏机制；周晓宇等[12-13]对落石撞击柔性防护结构数值模拟时均简化了减压环对整体结构受力性能的影响；汪敏等[14]进行了减压环的静力试验及动力有限元分析，给出了加载速度和铝套筒长度对减压环耗能性能及启动荷载的影响，但考虑的影响因素不够全面且没有给出减压环耗能大小的量化公式。