A, according to the requirements of design drawings, restore the stakes, and check the position, width, longitudinal slope, transverse slope and corresponding elevation of the subgrade centerline. According to the inspection results, the rectification plan can be prepared and submitted to the supervision engineer for approval before construction.

B, the soil subgrade is scraped or filled manually or mechanically, and it is shaped by mechanical rolling and renovation. When the fill is insufficient or the slope is washed by rain, the original slope will be dug into steps and filled in layers.

C, the surface of soil subgrade shall be leveled by bulldozer. When the shoveled soil is not enough to fill the depression, it shall be filled and compacted with the same soil as the subgrade. Within the range of 15cm of the renovated subgrade surface, loose large stones will be removed and compacted with the same filler as the subgrade.

D, the side ditch renovation should be carried out by hanging the line, and the longitudinal slopes of various ditches should be detected by instruments until the renovation meets the design specification requirements.

E, fill the roadbed on both sides of the overbilling width should be pre-dug. When the slope is short of soil, it must be dug into steps and compacted by layers.