Field Test Study on Frost Heaving Characteristics of Seasonally Frozen Soil Subgrade in Tibet
Relying on the reconstruction project of Latuo-Mangkang Highway in Tibet,the typical sub-grade section was selected,and temperature-moisture sensors and frost heaving meters were arranged at different heights,depths and lateral positions of the subgrade.The water content,temperature dis-tribution and frost heaving deformation at the subgrade section were monitored for a long time,and their distribution and variation laws in time and space were studied.The results show that the maxi-mum freezing depth of the left and right shoulders and the middle survey line is about 1.25m and 0.85m respectively.After a freeze-thaw cycle,water accumulated in the upper and lower range of sub-grade depth of-0.5m,but the soil water content decreased below the freezing depth,and some of the water in this area did not fall back after it migrated upward.The process of frost heaving deformation can be roughly divided into four stages:frost heaving development stage,frost heaving stability stage,freezing-thawing alternation stage and thawing settlement stage and corresponding time peri-ods.The range of-0.5～0m in the study section is a significant frost heaving area,and the tempera-ture amplitude,temperature difference and freezing depth of the right shoulder(shadow)survey line are the largest,so the yin-yang slope effect should be considered in the design of roads with similar trends in this area.
subgrade engineeringfrozen soilfrost-heaving characteristicsmonitoring test
NETL
NSTL
万方数据
