青藏铁路多年冻土区桥梁桩基沉降原因分析

摘要

Qinghai-Tibet railway was built railway bridge instead of railroad at K1401 + 888.The bridge was located in permafrost region of Tanggula Mountain main ridge.Ice cone problems have developed in areas of bridge and continuous uneven subsidence has appeared in some piers since the railway opened,these problems may threat safeties of the railway operation.The process of generation,development and solutions of ice cone and piers subsidence were introduced in this paper.The causes of diseases were obtained by comprehensive analysis,which were combined actions of natural climatic environment,heat exchange of groundwater,construction disturbance,stratum effective stress,stratum lithology etc.It is suggested that we should pay attention to heat exchange of groundwater in permafrost region during engineering investigation and design.At the same time,the thermal disturbance of frozen soil should be minimized as far as possible during construction and treatment of disease.%青藏铁路K1401 +888以桥代路大桥位于唐古拉山主脊的多年冻土区.自青藏铁路开通运营以来桥址区出现了冰锥病害,且部分桥墩发生持续不均匀沉降,给铁路运营安全带来较大影响.本文介绍了桥梁冰锥和墩台沉降病害的发生、发展和治理过程.通过分析得出产生病害的原因为自然气候环境、地下水的热交换、施工扰动、地层有效应力、地层岩性等多种因素的共同作用.建议在多年冻土区内进行工程勘察和设计时加强对冻土区地下水热交换问题的关注,施工和病害治理时尽量减小对冻土的热扰动.