Method for preventing and controlling freeze-expanded damage to water-containing subgrade in cold region and bunched low-temperature heat pipe

The invention discloses a method for preventing and controlling freeze-expanded damage to water-containing subgrade in a cold region and a bunched low-temperature heat pipe. The method is characterized in that a T-shaped bunched solar low-temperature heat pipe capable of transmitting solar energy or electric energy heat into the subgrade is arranged in the subgrade; when the environmental temperature is lower than 0 DEG C, a working medium on the evaporation segment of the low-temperature heat pipe absorbs solar energy heat and rises to be conducted into the condensation segment of the low-temperature heat pipe; on cloudy days, the working medium on the evaporation segment is heated through electric heating, and is conducted into the condensation segment of the low-temperature heat pipe; heat is transmitted into the water-containing subgrade through the condensation segment in order that the temperature of the water-containing subgrade is greater than the icing temperature; the working medium which releases heat returns back into the evaporation segment under the action of gravity to absorb heat, and the abovementioned work is performed circularly in order that the temperature of the water-containing subgrade is kept higher than the icing temperature, so that the occurrence of freeze-expanded damage to the subgrade is prevented. The method is simple and reliable, the phenomenon of frost heaving of the subgrade can be effectively avoided, and the transportation safety is ensured.