考虑非连续交界面影响的拼宽公路变形分析  

Deformation Analysis of Widened Highways Considering the Discontinuous Interface between New and Old Roadbed

作　　者：程树范 殷源 林康 CHENG Shu-fan;YIN Yuan;LIN Kang(Hubei Province Road and Bridge Group Co.Ltd.,Wuhan 430056,China;School of Civil Engineering,Wuhan University,Wuhan 430072,China)

机构地区：[1]湖北省路桥集团有限公司,武汉市430056 [2]武汉大学土木建筑工程学院,武汉市430072

出　　处：《公路》2024年第11期16-23,共8页Highway

基　　金：国家自然科学基金项目,项目编号51878521、42107175、12172280。

摘　　要：新、旧路面交界处开裂和路基差异沉降是拼宽公路运营期最为常见的灾害模式。为明确致灾机理及治理方法,考虑了土层交界面非连续变形,提出了一种简化的界面黏结-摩擦模型,并以京港奥高速公路改、扩建项目为依托,通过数值模拟手段分析了荷载作用下拼宽公路整体变形规律。研究表明:(1)土层界面抗剪性能弱于压实土体,是路基剪切破坏时的薄弱面和潜在破坏面;(2)黏结-摩擦模型可以较好描述路基交界面的力学性能,且无明显网格依耐性;(3)新、旧路基的刚度差是导致路面竖向非均匀变形的主要因素,且在较大竖向荷载作用下,界面上的切向分力会诱发交界面脱黏和新填筑路基水平位移,进而导致交界处路面开裂。因此,在进行公路拼宽设计时,应当重视新、旧路基差异导致的沉降差,以及交界面对路基整体性的影响。Cracking at the junction zone of new and old road surface and differential settlement of roadbeds are the most common defects during the operation period of widened highways.To define the defects mechanism and treatment methods,a simplified interface bonding-friction model considering the discontinuous deformation of soil layer interfaces is proposed in this paper.Based on the renovation and expansion project of the G4 Expressway(from Beijing to Hong Kong and Macao),the deformation regulation of the widened highway under vertical load is analyzed through numerical simulation methods.Research has shown that:(1)the shear resistance of the interface between soil layers is weaker than that of compacted soil,and being the weak zone and potential shear failure face;(2)the cohesion-friction model can better describe the mechanical properties of the interface between two soil layers without mesh dependence;and(3)the difference in stiffness of the new and old roadbeds is the main factor that leads to the non-uniform deformation in the vertical direction.Meanwhile,the tangential stress on the interface generated by vertical load can induce interface de-bonding and horizontal displacement of the newly filled roadbed which leads to the pavement cracking at the junction zone.Therefore,in the highway widening design,attention should be paid to the non-uniform settlement caused by the difference between the new and old roadbeds,as well as the impact of the interface on the overall integrity of the roadbed.

关 键 词：公路拼宽 界面模型 路基沉降 路面开裂 非连续变形 

分 类 号：U418.8[交通运输工程—道路与铁道工程]