Because the working surface inside the original culvert was very small, to speed up the binding of reinforcing bars and the installation and dismantling of sliding steel formwork, and to reduce the labor intensity of workers, a steel flatcar was used to transport the formed reinforcing bars and the cylindrical integral sliding steel formwork, and steel rails were laid along the entire length of the culvert. Therefore, construction joints were set on the cross-section during culvert construction, and the entire culvert was constructed in two stages, with the construction joints located as close as possible to the theoretical inflection point of the lower half of the circular structure. Construction of the lower part of the culvert began first at the upstream inlet, leaving outward lapped reinforcing bars according to specifications, treating the construction joints, and pre-embedding small steel plates to fix the steel rails. After demolding, the steel rails were laid and fixed. Construction of the upper arched part of the culvert also began at the upstream inlet. Since each culvert was equipped with a complete set of steel formwork, culverts No. 1 and No. 2 could be constructed in sections. The formed reinforcing bars were first delivered to the working surface using a steel flatcar. After one section was bound, a winch was used to slide the cylindrical steel formwork supported by the steel flatcar into place. Then, the concrete pump pipe was introduced into the steel formwork and concrete was poured. After the concrete reaches a certain strength, the formwork is removed and the culvert slides to the next section. When the concrete reaches a certain strength after the formwork is removed, cement mortar is injected into the crescent-shaped gap at the top of the circular culvert using pressure grouting to ensure the compactness of the culvert cross-section.