沥青混凝土小梁开裂损伤影响因素分析  

Analysis on Influencing Factors of Asphalt Concrete Beam Crack Damage

作　　者：张兰峰[1] 庞立果 ZHANG Lan-feng;PANG Li-guo(Guangdong Communications Polytechnic,Guangzhou Guangdong 510650,China;Guangdong Nanyue Transport Investment &Construction Co.,Ltd.,Guangzhou Guangdong 510650,China)

机构地区：[1]广东交通职业技术学院,广东广州510650 [2]广东省南粤交通投资建设有限公司,广东广州510101

出　　处：《公路交通科技》2019年第1期87-93,142,共8页Journal of Highway and Transportation Research and Development

基　　金：广东省交通运输厅科技项目(科技-2016-02-009)

摘　　要：为了研究沥青混凝土小梁裂缝在荷载作用下的扩展规律及其影响因素,应用扩展有限元法对预置裂缝的沥青混凝土小梁裂纹扩展进行了数值模拟。在小梁跨中底部预置裂缝,施加固定数值的位移荷载,将裂缝扩展影响因素分为荷载位置(跨中、距离跨中2 cm、距离跨中5 cm)、预设裂缝长度、材料力学参数(抗拉强度、断裂能)。计算结果表明:XFEM裂缝扩展路径不依赖于网格化分和单元边界,裂缝是从单元内部断开,呈现曲折形状,可以显示裂缝扩展的真实形态;裂缝扩展类型与荷载与裂缝的相对位置有关,当施加荷载作用线与裂缝重合时,裂缝扩展区域以受到拉应力为主,扩展类型体现为I型,若两者不重合,裂缝扩展区域以受到拉应力、剪应力的综合作用,裂缝扩展以I-II复合型为主;荷载作用位置离预设裂缝越远,最大主应力峰值、最大主应变峰值都越小,而且裂缝扩展长度也越小;小梁跨中底部的初始裂缝长度越小,裂缝扩展需要的断裂能就越大。改变抗拉强度和断裂能数值表明,抗拉强度的增加只是增大开裂需要的荷载,而断裂能改变不只改变开裂需要的荷载,而且改变小梁受力产生的变形。所以断裂能更能正确反映材料抗裂性能。In order to research the extension rule of crack in asphalt concrete beam and its influencing factors,the crack propagation in the asphalt concrete beam with preset crack is numerical simulated by using the extended finite element method. Crack is preset at the bottom of the beam midspan,exerting fixed displacement load. The influencing factors of crack propagation include loading position( 0,2,5 cm distance from midspan),preset crack length,material mechanical parameter( tensile strength,fracture energy). The calculation result shows that( 1) XFEM crack propagation path is independent of the gridding and element boundaries,the crack extensions from interior of the element,presenting the zigzag shape and displaying the true form of crack propagation;( 2) crack extension type is associated with the relative position of crack and load,when the exerted load line is coincidence with crack,the crack propagation region is controlled mainly by tensile stress,the extension type is type I,if both do not overlap,the crack propagation region is controlled both by tensile stress and shear stress,the crack propagation is given priority to I-II compound type;( 3) the farther the load position is from the preset crack,the smaller the maximum peak principal stress,the maximum peak principal strain and crack propagation length;( 4) the smaller the initial crack length at the bottom of the beam midspan,the greater the fracture energy which crack extension requires.The change of tensile strength or fracture energy indicates that the increase of tensile strength can only increasethe cracking load,while the change of fracture energy not only changes the cracking load,but also changes the deformation of the loaded beam,so fracture energy can more correctly reflect material crack resistance.

关 键 词：桥梁工程 裂缝扩展 数值模拟 XFEM 断裂能 位移不连续性 

分 类 号：U414.75[交通运输工程—道路与铁道工程]