Roadbed structure and roadbed construction method

The roadbed structure comprises a waterproof heating layer, a waterproof heat preservation layer and an upper roadbed layer, and edge covering soil layers are arranged on the two sides of a roadbed; the waterproof heat preservation layer comprises a drainage cushion layer, an XPS heat preservation plate and a lime soil cushion layer. The upper roadbed layer comprises a gravel soil layer, a bubble mixed light soil base layer and an asphalt pavement; the waterproof heating layer comprises waterproof walls on the two sides of the roadbed, and a heating facility is arranged between the waterproof walls. During construction, shallow salinized soil is removed to form a foundation pit, and after a cutoff wall and a heating facility are arranged in the foundation pit, salinized soil is backfilled; then a drainage cushion layer, an XPS heat preservation plate, a lime soil cushion layer, a gravel soil layer, a bubble mixed light soil base layer and an asphalt pavement are laid in sequence, and finally heat preservation