Research On Moisture And Temperature Monitoring And Intensity Change Of Subgrade In Seasonal Frozen Region

Seasonal frozen area diseases are mainly frost heaving and thaw settlement, highway roadbed diseases are mostly caused by the reduced subgrade strength, the main factors of the subgrade soil freeze-thaw damage are humidity changes and temperature changes with the season, but The direct reason is the change of subgrade strength after freeze-thaw cycles. Therefore, it is of great significance to take appropriate measures for the prevention and treatment of seasonal frozen area thaw damage, improve service levels highway and extend the road life by accessing to the data of seasonal frozen area subgrade soil temperature, humidity, intensity and variation.In order to study seasonal frozen area roadbed temperature and humidity variation, I independently developed the roadbed temperature and humidity remote automatic acquisition system, selected two roads and three sections to lay the temperature and humidity sensors, I use a remote roadbed subgrade acquisition system for continuous monitoring of temperature and humidity changes and take soil samples before and after freezing and thawing by artificial drilling method to measure the moisture content of subgrade; while using PANDA2variable energy penetrometer data collection subgrade strength and intensity of indoor simulated freeze-thaw cycle test to verify the results of the PANDA2variable energy penetrometer data. The results Showed that:remote embankment temperature and humidity acquisition system is fully functional, achieving a continuous collection of data of temperature and humidity within the roadbed various depths timely, and using wireless transmission technology to send data collected promptly and accurately to the client. Frozen subgrade of the median strip is at a depth greater than the sides of the shoulder, compared with the earth embankment freeze faster and has a deeper freezing depth, but began to melt later and has longer-lasting melting time; It is earlier and faster to melt of the surface of the sun than the nightside, higher embankment freezing more depth, while filling height is the same, smaller width frozen subgrade have greater freezing depth; when filling materials and locations are the same in the process of freeze-thaw cycles,higher embankment soil moisture has smaller rate. Snow melting on pavement will penetrate the subgrade moisture to increase the rate; after freeze-thaw cycles PANDA2penetration of variable energy meter data collected at the scene showed that the strength of subgrade soil in May after melting decreased greatly, under the same conditions, After freeze-thaw cycles the higher embankment, the greater the subgrade strength; laboratory simulation tests showed that the water content, degree of compaction and freeze-thaw cycle are important factors affecting the strength of the subgrade, After freeze-thaw cycle, the resilient modulus of the subgrade soil tends to be small, with the increase in the number of freeze-thaw cycles this trend more and more.