考虑拱脚下沉的桩承式路堤土拱效应弹簧活动门试验  

Spring-based Trapdoor Experimental Investigation on Soil Arching of Pile-supported Embankment Considering Arch Foot Settlement

作　　者：张玲[1,2,3] 周杰 周帅 邓孟超[1,2,3] 赵明华[1,2,3] ZHANG Ling;ZHOU Jie;ZHOU Shuai;DENG Meng-chao;ZHAO Ming-hua(College of Civil Engineering,Hunan University,Changsha 410082,Hunan,China;Key Laboratory of Building Safety and Energy Efficiency of the Ministry of Education,Hunan University,Changsha 410082,Hunan,China;National International Joint Research Center for Building Safety and Environment,Hunan University,Changsha 410082,Hunan,China)

机构地区：[1]湖南大学土木工程学院,湖南长沙410082 [2]湖南大学建筑安全与节能教育部重点实验室,湖南长沙410082 [3]湖南大学国家级建筑安全与环境国际联合研究中心,湖南长沙410082

出　　处：《中国公路学报》2025年第2期114-122,共9页China Journal of Highway and Transport

基　　金：国家自然科学基金项目(52078205,52378340);岩土力学与工程国家重点实验室开放基金课题(SKLGME022016);湖南省研究生科研创新项目(CX20240037)。

摘　　要：土拱效应是桩承式路堤荷载传递的主要机理之一。摩擦刚性桩、水泥土桩、碎石桩等桩体复合地基支承的路堤,在路堤荷载和车辆局部荷载作用下,桩顶会产生沉降,其对路堤土拱效应的影响不容忽视。而传统活动门试验研究土拱效应时,拱脚固定,无法考虑桩顶沉降(拱脚下沉)对路堤土拱形态和荷载传递的影响。为此,设计了一种拱脚可下沉的多跨弹簧活动门试验装置,通过局部面荷载模拟车辆荷载,并采用不同刚度的弹簧支撑活动块,用于模拟桩和桩间土,开展了15组弹簧活动门正交试验和1组活动门固定的参照试验。在填土自重和局部荷载作用施加后,分别通过土压力盒和激光位移计监测土拱影响区域内的土压力以及拱脚和活动门的位移,并基于DIC数字影像技术重现了土拱形态的演化过程。试验结果表明:拱脚下沉对土拱效应存在削弱作用。在不同加载阶段,削弱作用呈现出明显差异,且活动门刚度愈大,削弱作用愈明显。此外,填土自重荷载下,拱脚下沉时土拱高度降低,有利于抑制填土内部沉降差向上发展,但土拱影响宽度增加,使土拱形态从陡拱演化为坦拱。局部荷载施加后,拱脚下沉时中跨土拱稳定性降低,促使荷载向相邻跨传递,从而调动相邻跨的土拱的发展,以共同承担局部荷载作用。Soil arching is a primary load-transfer mechanism in pile-supported embankments.For embankments supported by a composite foundation with rigid friction piles,cement soil piles,and gravel piles,the settlement of the pile head under embankment fill and localized vehicle loads significantly impacts the soil arching of the embankment.However,traditional trapdoor models usually use fixed supports,which do not account for the influence of pile head(or arch foot)settlement on the soil arch shape and load transfer of the embankments.To address this,a multispan spring-based trapdoor test apparatus with movable arch feet was designed in this study.The vehicle loads were simulated with localized surface loads,and movable blocks with springs of varying stiffnesses were used to model the piles and the soil between the piles.Fifteen orthogonal spring-based trapdoor tests and one reference test with a fixed trapdoor were conducted.Under the self-weight of the fill and localized loads,the earth pressure in the affected area of the soil arching and the displacement of the arch foot and trapdoor were monitored using earth pressure cells and laser displacement meters,respectively.The evolution process of the soil arch morphology was reproduced using digital image correlation(DIC)technology.The test results show that the arch foot settlement weakens soil arching.The weakening effect varies across different arching states and becomes more prominent with an increase in trapdoor stiffness.Additionally,the arch foot settlement under the fill weight significantly decreased the soil arching height,restricted the upward propagation of the differential settlement within the embankment,and expanded the affected width of the soil arch,causing a transformation from a steep to a flat soil arch.Under a localized load,arch foot settlement significantly reduces the stability of the mid-span soil arch,promotes load transfer to the adjacent span,and mobilizes the soil arching of the adjacent span to carry the load.

关 键 词：路基工程 桩承式路堤 弹簧活动门 土拱效应 拱脚下沉 局部荷载 

分 类 号：U416[交通运输工程—道路与铁道工程]