摘要
青藏铁路作为国家重要战略通道和西藏经济发展的关键支撑,在其建设中广泛采用了以桥代路的冻土保护措施。然而,随着全球气候变暖和人类工程活动增加,多年冻土区路桥过渡段出现了大量工程病害,如路基沉降、桥梁结构变形等。本文结合以往研究资料,从病害类型、病害成因、现有处置措施、面临问题分析四个方面,对路桥过渡段工程病害的研究现状进行梳理和总结,结合青藏铁路路桥过渡段病害一体化处置技术试验示范工程的最新观测结果,提出未来工程病害处置方向和建议。桥体结构热源作用诱发的非均匀冻土退化是路桥过渡段差异沉降的主要原因,而桥梁结构变形一方面由冻土地基承载力下降引起,另一方面则主要受到了桥台背后填土的季节冻胀作用。随着青藏高原暖湿化持续加剧,未来青藏铁路多年冻土区路桥过渡段面临更高的病害发生风险,传统补强措施已不足以应对未来风险挑战。一体化处置技术对于路桥过渡段工程病害处置展现出了良好成效,在一年内实现了高温冻土向低温冻土的转变,同时实现稳定性的快速提升,该技术对于进一步提升青藏铁路工程质量和可持续发展具有现实意义。
The Qinghai-Xizang Railway(QXR),a crucial strategic corridor and vital support for Xizang’s economic development in China,extensively employed bridges instead of embankments to protect permafrost during its construction.A total of 156 kilometers of the railway consists of bridges rather than conventional embankments,with 447 bridges constructed,including 125 kilometers of dry bridges,leading to a higher proportion of embankment-bridge transition sections(EBTSs)compared to ordinary railways.However,with global warming and increasing human engineering activities,numerous engineering distresses have emerged in the EBTS in permafrost regions,such as differential embankment settlement,subsidence of wing walls,and bridge structure deformation.Addressing these issues is crucial for ensuring the safe and sustainable operation of this vital infrastructure.This paper reviews and summarizes the current research on engineering distress of the EBTS along the QXR from four aspects:distress types,causes,existing treatment measures,and analysis of faced problems.Additionally,it integrates the latest observations from the QXR’s experimental project on integrated treatment technologies,proposing future directions and recommendations for engineering distress treatment in EBTSs.Research findings indicate that the non-uniform degradation of permafrost induced by the thermal effects of bridge structures is the primary cause of differential settlements in EBTS,contributing up to approximately 50%of the observed settlement.For the numerous dry bridges along the QXR,foundation settlement constitutes the main source of embankment settlement in EBTSs,accounting for over 80%of the total settlement.Bridge structural deformation primarily results from decreased bearing capacity of permafrost foundations and seasonal frost heaving of backfill.Given the lower elevation of EBTSs,protection-cone slopes are subjected to substantial groundwater thermal erosion and intense frost heave,leading to subsidence and cracking deformations.With ongoing warm and rainfall increases on the Qinghai-Xizang Plateau,EBTSs along the QXR face increased risks of distress occurrence in the future.Traditional reinforcement measures are inadequate to address future challenges.The integrated treatment technology has shown promising results in addressing engineering distresses in EBTSs.This technology employs a multi-faceted approach,utilizing innovations such as horizontal thermosyphons,ventilated slope and targeted thermosyphon arrays to achieve comprehensive cooling and regulation of embankment slopes,cone slopes,and foundations.Field monitoring data indicate that this technology has successfully transformed warm permafrost into cryogenic permafrost within a year,concurrently achieving rapid enhancement in structural stability.This technology holds practical significance for enhancing the engineering quality and promoting sustainable development of the railway.
作者
李林
冯辉
陈坤
LI Lin;FENG Hui;CHEN Kun(China Railway 12th Bureau Group Railway Maintenance Engineering,Chengdu 610073,China;Qinghai-Tibet Railway Company,Xining 810000,China;State Key Laboratory of Cryospheric Science and Frozen Soil Engineering,Northwest Institute of Eco-Environment and Resources,Chinese Academy of Sciences,Lanzhou 730000,China)
出处
《冰川冻土》
2025年第1期199-212,共14页
Journal of Glaciology and Geocryology
基金
国家自然科学基金项目(42071095)
甘肃省青年科技基金计划项目(22JR5RA086)
青藏集团公司科技项目(QZ2022-G02)资助。
关键词
多年冻土
路桥过渡段
差异沉降
桥梁结构变形
青藏铁路
permafrost
embankment-bridge transition section
differential settlement
bridge structure deformation
Qinghai-Xizang Railway
