基于有限元仿真的挡土墙墙顶护栏车辆撞击分析

Vehicle Impact Analysis of Retaining Wall Top Guardrails Based on Finite Element Simulation

随着高速公路车辆撞击护栏事故的增多,为了缓冲和消散挡土墙结构所受墙顶护栏的车辆撞击力,提出护栏与挡土墙的分离式设计方案;依托沈阳至海口国家高速公路汕尾陆丰至深圳龙岗段改扩建工程,利用显式动力有限元仿真方法,从能量变化、挡土墙位移等方面进行动力响应计算与分析,提取挡土墙结构的内力效应,并采用静力等效方法进行结构承载能力安全性分析,针对分离间距和挡土墙节段间连接等开展参数化分析。结果表明:墙顶护栏与挡土墙之间的缓冲土体可以较好地消散车辆对护栏的水平撞击力,挡土墙结构在车辆对护栏的水平撞击力偶然组合下满足极限状态承载能力要求;随着分离间距的增加,缓冲土体对车辆撞击力的消散作用逐渐增强,可有效减弱挡土墙面板和底板的弯曲效应,而挡土墙节段间的连接仅可有效减弱挡土墙底板的弯曲效应,对面板的弯曲效应影响较小。

With increase of vehicle impact accidents on guardrails of expressways,in order to buffer and dissipate vehicle impact force on top of retaining wall structure,a separate design scheme of guardrails and retaining walls was put forward.Based on the reconstruction and expansion project of Shenyang to Haikou national highway Lufeng(Shanwei)to Longgang(Shenzhen)section,Guangdong province,dynamic response of retaining walls was calculated and analyzed from aspects of energy change and displacement of retaining walls by using explicit dynamic finite element simulation method.Internal force effect of retai ning wall structure was extracted,and safety analysis of structural bearing capacity was carried out by using static equivalent method.Parametric analysis was carried out for separation spacing and connection between retaining wall segments.The results show that the buffer soil between top barriers and retaining walls can dissipate the horizontal impact force of vehicles on barriers,and the retaining wall structure can meet requirements of ultimate state bearing capacity under accidental combination of the horizontal impact force of the vehicles on the barriers.The dissipation effect of the buffer soil on the vehicle impact force gradually increases with increase of separation distance.Bending effect of retaining wall panels and floors can be effectively reduced,while connection between retaining wall segments can only effectively reduce the bending effect of retaining wall floors,and has little effect on the bending effect of retaining wall panels.