On April 15, with the strong support of higher-level units and the joint efforts of the Mianzhu Municipal Transport Bureau, Mianmao Company and all participating construction units, the Heidongyan Bridge, a controlling project of the section from the exit of Heitantou Tunnel to Lanjiayan Tunnel on the Mianmao Highway (Mianzhu section), was successfully closed. The bridge is a continuous rigid-frame bridge with a pier height of 85 meters, the tallest pier on the Mianmao Highway. Construction is highly difficult, and the geological conditions at the bridge site are complex.
It is understood that the Heidongyan Bridge crosses the Qingshui River, where the riverbed is about 45 meters wide. Affected by the "5.12" earthquake, the "8.13" debris flow and the "7.9" flood, the mountains along the upstream section have collapsed, with numerous scattered rocks and debris flow deposits, and the mountain slope exceeds 75°, making construction extremely difficult.
After the bridge is completed, construction materials can be transported via the completed road section from Qipanshi Tunnel all the way to Ergangqiao Bridge, shortening the construction access road by nearly 8 kilometers. This will greatly reduce the adverse impact on project construction caused by access road closures during the flood season, and lay a solid foundation for achieving full-line breakthrough of the project in June this year and full-line trial operation by the end of the year.