Excavate and remove all soft ground within a 30m width below the box girder, and replace it with gravel (quarried stone) containing more than 60% stone content. On hillside sections, clear the surface to expose hard rock and set a cross slope controlled within 3% to facilitate timely drainage of rainwater. If the longitudinal slope is too steep, adopt a stepped arrangement to facilitate level support and bedding of the bottom brackets.

　　On the upstream side near the access road, excavate drainage ditches to lower the water level elevation, preventing rainwater and other water from flowing into the scaffold area and causing the scaffold to settle.