Moisture Content Distribution and Variation Law of Highway Subgrade in High-Latitude and Low-Altitude Deep Seasonal Frozen Ground Region

According to the tracking observation of the highway subgrade moisture content in the high-latitude and low-altitude seasonal frozen ground region in Heilongjiang province, the time-varying variation law of the subgrade moisture content and the distribution state of the subgrade moisture content at different depths are analysed to confirm that the distribution pattern of moisture content in fine-grained soil subgrade does not strictly conform to capillary ascent distribution law of groundwater (or surface water), which is related to the coverage and gap of the pavement, slope water seepage and water-holding capacity of the subgrade soil. In general, the distribution state can be roughly divided into B distribution, C distribution, D distribution and S distribution. As the distribution of subgrade moisture content is no longer the conventional pattern of “low up and high down”, the control of subgrade height should not be rigidly stuck to the subgrade height controlled by capillary ascent height, while multiple measures should be taken to ensure water temperature and strength stability of subgrade.