CRTSⅢ型板式无砟轨道底座横向裂缝成因及影响规律研究  

Study on Causes and Influence Law of Transverse Cracks in CRTSⅢ Ballastless Track Base

作　　者：李艳[1] LI Yan(China Railway Siyuan Survey and Design Group Co.,Ltd.,Wuhan 430063,China)

机构地区：[1]中铁第四勘察设计院集团有限公司,武汉430063

出　　处：《铁道标准设计》2022年第6期21-26,共6页Railway Standard Design

基　　金：中铁第四勘察设计院集团有限公司科研课题(2020K019,2020K026)。

摘　　要：针对目前高速铁路CRTSⅢ型板式无砟轨道底座凹槽四角开裂病害,建立桥上CRTSⅢ型板式无砟轨道底座凹槽有限元模型,基于多种温度荷载工况研究温度作用下底座板凹槽应力分布规律及裂缝成因;基于不同底座板凹槽结构形式探讨对四角裂缝的影响规律,并提出相应优化措施。研究发现,负温度梯度对底座板凹槽四角裂缝影响最为明显,当负温度梯度超过25℃/m时,四角混凝土拉应力最大值为2.5 MPa,超过混凝土抗拉强度标准值;预埋钢筋布置数量减少至18根时,凹槽应力峰值可降为2.28 MPa,低于混凝土抗拉强度标准值;相同18根预埋钢筋、不同布置方案下,凹槽应力峰值分别为2.28,2.49 MPa。研究结果表明:负温度梯度荷载是造成凹槽四角开裂的重要影响因素,通过适当减少靠近凹槽的横向两侧钢筋数量,优化凹槽四周预埋钢筋布置方式可有效降低底座板凹槽裂纹的产生。In order to study the four-corner cracking of the base groove of CRTSⅢ slab ballastless track of high-speed railway, a finite element model of the base groove of CRTSⅢ slab ballastless track on the bridge is established. Based on a variety of temperature load cases, the stress distribution and crack causes of the base plate groove under temperature are studied, the influences of different groove structure forms of base plate on four-corner cracks are discussed, and corresponding optimization measures are put forward. The research reveals that the negative temperature gradient has the most obvious effect on the four-corner cracks of the base plate groove;when the negative temperature gradient exceeds 25 ℃/m, the maximum tensile stress of the four-corner concrete is 2.5 MPa, which exceeds the standard value of concrete tensile strength;the number of embedded reinforcement arrangement is reduced to 18 grooves, and the peak stress can be reduced to 2.28 MPa, which is lower than the standard value of concrete tensile strength;under the same 18 embedded reinforcement and different layout schemes, the peak stress of the groove is 2.28 MPa and 2.49 MPa respectively. The results show that the negative temperature gradient load is an important factor causing the four-corner crack of the groove. By appropriately reducing the number of transverse reinforcement on both sides near the groove and optimizing the layout of embedded reinforcement around the groove, the cracks of the base plate groove can be effectively reduced.

关 键 词：高速铁路 无砟轨道 底座凹槽 温度荷载 裂缝成因 影响因素 防控措施 

分 类 号：U213.244[交通运输工程—道路与铁道工程] U213.242