青藏公路普通填土路基长期变形特征与路基病害调查分析

基于长期监测系统2004－2011年现场监测数据，系统分析青藏公路近年来冻土路基变形特征及路基病害原因。结果表明，目前青藏公路普通填土路基变形主要以融沉变形为主，且沉降变形仍将继续发展。根据路基各部位变形速率的差异性，可以将路基变形划分为均匀与不均匀变形两大类。路基平均沉降速率在2～55 mm/a之间，河流沟谷地带路基变形速率最大，山区路基变形速率次之，其他地貌区路基变形速率最小。路基纵向变形对路面影响较大，主要形成波浪等病害，对道路行车舒适性与安全性有较大隐患。路基横向变形主要产生路基纵向裂隙病害，导致路基向变形较严重一侧坍塌，对路基整体稳定性有较大影响。通过2012年对青藏公路路基病害的调查研究发现，青藏公路多年冻土区路基优、良、中、次、差的比例分别为57.39% 、28.12%、9.71%、4.60%、0.17%。通过对青藏公路普通填土路基长期变形特征的分析，期望为青藏公路的整治维修提供参考，同时为未来青藏高速公路的设计和维护提供依据。

Analysis of disease investigation and long-term deformation characteristics of common fill embankment of the Qinghai-Tibet Highway

According to the long-term monitoring data of the Qinghai-Tibet Highway from 2004 to 2011, we systematically analyze the characteristics of permafrost embankment deformation and the reasons of roadbed disease. Our studies show that the thawing-sinking is the major deformation behavior of common fill embankment, and the settlement may be further increased in future. The types of deformation can be divided into uniform and non-uniform deformations in terms of the deformation rate differences of each part of embankment. The average deformation rate is in the range of 0.2-5.5 cm/a. The deformation rates of embankment are different in different regions. In river valley regions, the deformation rate is the maximum; it is followed in the mountain regions, and the minimum is in other regions. The types of deformation can also be divided into longitudinal and lateral embankment deformations depending on the deformation direction. The longitudinal embankment deformation has the greatest effects on the pavement and results in the wave-shaped pavement disease, which induces uncomfortable driving situations and the road traffic safety. The lateral embankment deformation results in longitudinal cracks in embankment, which causes the collapse towards to the severe deformation side, and thus influences its overall stability. Based on the investigation of the Qinghai-Tibet Highway roadbed diseases in 2012, it has been found that the proportions of embankment status grades of very good, good, fair, poor and very poor are 57.39%, 28.12%, 9.71%, 4.60% and 0.17%, respectively. This study provides a reference for maintaining the stability of Qinghai-Tibet Highway and a basis for route selection and engineering design in future.