In item A, the cement stabilized soil base should be constructed by plant mixing method, and lime stabilized soil and lime stabilized soil can be constructed by road mixing method or plant mixing method. BC, lime stabilized soil base construction temperature should be not less than 5℃. And it will be completed one month before the first refreezing. The compaction thickness of each layer is not less than 100mm and not more than 200 mm. After the compaction of D lime-fly ash stabilized soil base, it should be cured in time, and the curing period should be not less than 7 days, and the surface should always be moist.