沟谷地形填土长期蠕变下涵洞受力机理分析  

Analysis of Stress Mechanism of Culvert in Trench Terrain Under Long-term Creep of backfill

作　　者：代竞翔 陈保国[1] 任国卿 任一青 DAI Jingxiang;CHEN Baoguo;REN Guoqing;REN Yiqing(Faculty of Engineering,China University of Geosciences(Wuhan),Wuhan,Hubei 430074,China)

机构地区：[1]中国地质大学(武汉)工程学院,湖北武汉430074

出　　处：《公路工程》2025年第1期121-128,245,共9页Highway Engineering

基　　金：国家自然科学基金项目(52178370)。

摘　　要：埋设于天然沟谷中的箱涵在高填土长期荷载作用下,涵-土体系发生应力重分布,影响涵洞长期使用的安全性。采用数值模拟方法对沟谷地形中的涵洞进行了600个月的模拟分析,得出填土蠕变特性和涵周土压力的变化规律,揭示了填土应力传递机理。在此基础上建立力学模型,推导得出涵顶平面长期土压力计算方法,并与数值模拟结果进行对比验证。研究发现:因土体蠕变,填土顶面沉降较施工完毕时增大了60%左右,涵侧外土体工后沉降达到总沉降量的40%,工后沉降主要集中于前150个月;越靠近填土顶面,相邻土层的差异沉降越小,受土体蠕变的影响也越小。涵顶平面竖向土压力随时间呈波动规律,并逐渐趋于填土自重,最终涵顶平均土压力减小19%,涵侧平均土压力增大39%;而涵侧水平土压力随时间逐渐增大,最终趋于稳定,水平土压力增大了193%,同时,基底角点接触压力减小24%,基底中心处接触压力减小了4%。填土蠕变使得沟谷内填土应力分布趋于均匀,应力集中现象逐渐减弱甚至消失。涵洞设计中应考虑蠕变引起的涵周土压力的变化,避免结构病害。The box culvert buried in natural valleys experiences stress redistribution in the culvert soil system under long-term loads from high fill soil,which affects the safety of the culvert's long-term use.The numerical method was conducted to simulate the performance of culvert in trench terrain for 600 months.The variation laws of the creep deformation of backfill and earth pressures around the culvert were obtained,and the stress transfer mechanism in backfill was detected.moreover,the theoretical expression for calculating the long-term earth pressure acting on the culvert top plain were deduced based on a mechanical model.And compare and verify with numerical simulation results.Research results show that:due to soil creep,the backfill surface settlement increases by about 60%compared with the construction period,the post-construction settlement of the soil outside the culvert reaches to 40%of the total settlement,the post-construction settlement mainly occurs in the first 150 months.The closer to the top of the fill,the smaller the differential settlement of the adjacent soil layer due to the less impact of soil creep.The vertical earth pressure on the culvert top plane fluctuates with time and gradually tends to the overburden weight of the backfill.In the end,the average vertical earth pressure on the culvert top decreases by 19%and the average vertical earth pressure on the culvert side increases by 39%.The horizontal earth pressures acting on the both sidewalls gradually increase with time and eventually becomes stable,the horizontal earth pressure increases by 193%,meanwhile,the foundation contact pressure at the corner of the culvert basement decreases by 24%,and the foundation contact pressure at the center of the basement decreases by 4%.The creep of backfill makes the stress distribution of fill in trench to be more uniform,and the stress concentration phenomenon gradually weakens or even disappears.The variation of earth pressure around culvert caused by soil creep should be considered in culvert design

关 键 词：路基工程 涵洞 沟谷 蠕变 应力重分布 沉降 

分 类 号：U449[建筑科学—桥梁与隧道工程]