In the early morning of September 10, with the completion of the pouring of the last square of the left continuous beam of the Yanjiaping Bridge on the Yichang section of Yilai Expressway, the bridge successfully achieved a double-spread integration. At this point, the four sections invested by Hubei Communications Investment Group, organized and constructed by Yichang Construction Company, and undertaken by China Railway Construction Bridge Bureau have been fully completed.
Yanjiaping Bridge, as the thickest concrete continuous rigid structure bridge with the thickest pile diameter (2.5m), the longest pile length (80m), the highest pier column (154.075m), the largest span (145m), and the most difficult construction, has encountered many construction problems since the start of construction in April 2022.
The pile foundation construction has encountered a difficult "hard bone" again. Faced with the strong development of beaded caves inside the karst landform, the project department has successively tried drilling and pile driving processes such as rotary drilling, reverse cycle method, and impact drilling, and found that neither the progress nor the construction safety can meet the requirements. According to Li Chao, the head of the Yanjiaping Bridge Construction Site, the project department finally chose a high-cost full-bore rotary drilling rig, which not only increased the construction speed by 8 to 10 times, but also exceeded the national standard for pile quality.
In the process of pier column pouring, the project department adopted the most advanced hydraulic climbing technology in China, effectively solving the problems of difficult operation and low accuracy of high piers, and improving efficiency by 1.5 times. In order to overcome the influence of concrete strength in winter cold, the project department adopts an external mold spraying of polyurethane insulation material and places a steam health machine inside the pier to generate high-temperature steam to keep the pier body heated and ensure the quality of the pier column forming.
It is understood that with the completion of the three control projects of Wufengshan Tunnel, Chaibuxi Super Bridge and Yanjiaping Bridge, the entire subgrade and bridge projects of the Yichang section of the Yilai Expressway have entered the final stage, and the construction of the second and third phases has been fully started. Up to now, the project has completed an investment of 1228.81 million yuan this year, accounting for 82.47% of the annual plan; the cumulative investment of 16025.03 million yuan has been completed, accounting for 95.47% of the total estimated investment. (Reporter Song Yujie, Correspondents Gong Qian, Gao Junlong, Photography Li Zhi)
