兰新高铁甘青段路基冻胀自动监测及分析研究

为查明兰新高铁甘青段路基冻胀变形原因和影响因素,提出相应的冻胀处理措施,将路基冻胀变形控制在允许范围之内,采用自动监测系统,对路肩以下5 m范围内路基的冻结深度、水分、冻胀变形等进行监测,并对监测结果进行统计分析和深入研究。研究结果表明:路基冻结深度的发展主要受气温的影响,基床表层以下填料含水量随着冻结深度增加缓慢增加;基床表层及基床底层上部1.0 m范围冻胀量占总冻胀量的80%以上;低路堤地段冻胀最严重。为减少路基冻胀量,设计及施工时应采用全冻结深度防冻胀方案,以填料防冻胀为主,辅以防水、疏水和隔热等综合措施;低路堤地段防冻胀措施应适当加强。

Automatic Monitoring and Analysis of Subgrade Frost Heave in Gan-Qing section of Lanzhou-Uramqi High-speed Railway

In order to find out the causes and influencing factors of frost heaving deformation of the subgrade in Gan-Qing section of Lanzhou-Uramqi high-speed railway, corresponding frost heaving treatment measures are proposed to control the frost heaving deformation of subgrade within the allowable range. Automatic monitoring system is used to monitor freezing depth, moisture, and frost heaving deformation of subgrade within 5 m below the shoulder. Statistical analysis and thorough study are conducted to verify the monitoring results. Research results indicate that the development of subgrade freezing depth is mainly affected by temperature, and the water content of the filler below the surface layer of subgrade bed increases slowly with the increase of the freezing depth; the frost heaving amount of surface layer and upper 1.0 m rang of bottom layer of subgrade bed coves more than 80% of the total frost heaving; the frost heaving in low embankment is the most serious. In order to reduce the amount of subgrade frost heave, anti-frost in full freezing depth should be adopted during design and construction with focus on anti-frost fillers assisted with comprehensive measures such as water proof, hydrophobic and heat insulation. Anti-frost in low embankment section should be strengthen.