Unpowered anti-frost anti-heave heat gathering device and subgrade thereof

An unpowered anti-frost anti-heave heat gathering subgrade, comprising:

• a subgrade (10);
• and
• an unpowered anti-frost anti-heave heat gathering device, comprising a solar heat absorber (3), a circulating tube (4), a transducer (5), and a heat gathering tube (6), wherein the solar heat absorber (3) and the transducer (5) are connected by the circulating tube (4) to form a circulation loop, a liquid state circulating working medium flows in the circulation loop, the solar heat absorber (3) is configured to absorb solar energy, and transfer heat to the transducer (5) through the liquid state circulating working medium, and the heat gathering tube (6) comprises a heat absorption section (61) and a heat release section (62) in communication, the heat absorption section (61) is inserted into the transducer (5) for absorbing heat from the transducer (5) and transferring heat to the heat release section (62), and the heat release section (62) is inserted into a subgrade (10) for heating the subgrade (10),
• wherein the solar heat absorber (3) is mounted outside the subgrade (10), and the heat release section (62) of the heat gathering tube (6) is inserted inside the subgrade (10).