盐湖漫溢对多年冻土区桥梁墩台影响对策研究

Research on countermeasures for the impact of Yanhu lake overflow on bridge piers and abutments in permafrost regions

近年来,青藏高原多年冻土区盐湖面积不断扩大,漫溢后形成高矿化度水流流经铁路、公路的桥梁墩台,给线路运营造成了较大的安全隐患。针对盐湖漫溢河道处的桥梁工程进行研究,分析了盐湖漫溢对桥梁墩台带来的主要影响,提出了针对性的防治对策,并基于现场监测数据对工程效果进行了评价。主要结论包括:高矿化度水流对桥梁墩台造成的影响主要有河道下切严重,对地基多年冻土热干扰严重和对桥墩及基础混凝土腐蚀。针对高矿化度水流对桥梁墩台的影响,提出了区域河流疏导和冻土防护、桥墩基础冻土热防护、桥梁结构构造防腐蚀3个方面的整治技术;根据初期监测数据分析,高矿化度水流流量较大,造成下部冻土退化严重,但在合理的整治工程实施后,近1年多来未发现桥梁墩台变形。同时,地温监测数据验证了热棒具有保持多年冻土稳定的作用。

In recent years,the area of Yanhu lake in permafrost areas of the Qinghai Tibet Plateau has been continuously expanding,and after overflowing,high salinity water flows through the bridge piers and abutments of railways and highways,posing significant safety hazards to the operation of the railway lines.A study was conducted on the bridge engineering at the overflow channel of the Yanhu lake,analyzing the main impact of Yanhu lake overflow on bridge piers and abutments.Targeted prevention and control measures were proposed,and the engineering effect was evaluated based on on-site monitoring data.The main conclusions include:The impact of high salinity water flow on bridge piers and abutments mainly including river channel slices downwards,severe thermal interference to permafrost foundation,and corrosion to bridge piers and foundation concrete;Three remediation technologies have been proposed to eliminate the impact of high salinity water flow on bridge piers and abutments,including river training and permafrost protection,thermal protection of frozen soil on bridge pier foundations,and corrosion prevention of bridge structure construction;According to the initial monitoring data analysis,the high salinity water flow rate is large,causing severe degradation of the lower frozen soil.However,after the implementation of reasonable remediation projects,no deformation of bridge piers and abutments has been found in the past year.At the same time,the ground temperature monitoring data verified that the heat pipes has the function of maintaining the stability of permafrost.