Facing the Challenge with Confidence: A Chronicle of the Dali Siphon Project

　　

 

　　From July 2016 to the present, the Sixth Engineering Project Department has successively implemented the installation projects of the Dali Shuanglang, Xizhou, and the Third Waterworks siphon pipes. After the continuous implementation of these three projects, the project department's construction management personnel have gained rich experience in water construction, mastered the relevant technologies of siphon pipe water production, installation, and pipe laying, filling the gap in the project department's implementation of water engineering construction.

 

　　Siphon pipes belong to the water intake pipes of waterworks, and their length and diameter are designed according to the water supply capacity of the waterworks. The three waterworks siphon pipes implemented by the Sixth Engineering Department are all spiral welded steel pipes with different diameters and lengths. Pontoon fabrication and installation, pipe laying, underwater trench excavation, and floating transportation of pipes and sand and gravel are the key processes of the project. In the process of successive implementation of the three projects, the project department carefully managed, earnestly learned and summarized, and met the owner's requirements for construction period and quality.

Water Construction Pontoon

 

Shuanglang Waterworks Siphon Pipe Intake Head Rack

 

Shuanglang Waterworks Siphon Pipe Intake Head Rack Cover Fabrication

 

Pipeline Assembly Platform

 

Siphon Pipe Water Transportation

 

　　The Shuanglang Waterworks siphon pipe was the first water construction project implemented by the project department. Before the project implementation, the project department had never had similar construction and management experience. Most of the colleagues came from inland provinces, and they rarely faced large rivers and lakes in their daily lives, let alone their understanding of water and underwater construction. The start date was approaching day by day, and the plans were repeatedly rejected. Through repeated discussions, in-depth understanding of the construction drawings, seeking advice and learning from friends and colleagues with relevant experience, and multiple discussions with the construction team, the project department finally determined two key construction processes—the floating method and the pipe laying construction.

 

　　The Shuanglang Waterworks siphon pipe consists of two Φ530×12 spiral welded steel pipes, with a total length of 515m per pipe, an underwater section of about 500m, and a land section of about 15m. The distance between the two pipes is 10m. The floating method solved a series of problems such as sea transportation, underwater pipe trench excavation, pipe foundation treatment, and top backfill. The pipe laying construction method successfully solved problems related to pipe water entry positioning. Everyone started the project's preliminary preparation work in anxiety and anticipation, without paying attention to the beautiful scenery and numerous tourists of Erhai Lake. The fabrication of the pontoon was the first step in the preparation work. There are no large transport tugboats on Erhai Lake. If rented from the coast, the price is high, the transportation cycle is long, the construction period is delayed, and the cost is increased. Based on the characteristics of the project construction operation, after careful calculation, the project department decided to build an inverted T-shaped pontoon to meet the requirements of the siphon pipe sea surface construction operation. Watching the pontoon take shape day by day, the colleagues were full of anticipation. When an orange pontoon equipped with power slowly advanced into the depths of Erhai Lake, everyone was excited. That night, everyone celebrated with drinks. The first step, we succeeded.

 

　　The next task was the pipe trench excavation. The water depth of the operation area was 11m, and the arm length of an ordinary excavator was insufficient to meet the requirements of underwater excavation operations. After inquiring everywhere, the project department rented a modified long-arm excavator from the market. After one month of hard work, the underwater excavation of the 1000m pipe trench was successfully completed. All subsequent work proceeded according to the project department's predetermined plan, step by step verifying the reliability and rigor of the construction plan.

 

Xizhou Siphon Pipe Pipeline Assembly Steel Platform

Xizhou Waterworks Siphon Pipe

 

　　With the construction experience of the Shuanglang Waterworks siphon pipe, the construction of the Xizhou Waterworks siphon pipe was much easier. Due to the tight construction period, the work of Xizhou Waterworks and Shuanglang Waterworks was basically carried out simultaneously in the later stage. By the end of March, the construction of the siphon pipes of the two waterworks was completed.

 

　　During the construction of the siphon pipes, the project department attached great importance to quality, safety, and environmental protection. In terms of quality management, to ensure welding quality, the project department invited the company's quality and technology department to conduct business skills assessments for certified welders, and continuously supervised and inspected the construction quality during the project implementation. In terms of safety management, the project department strictly implemented the company's safety management system, standardized the on-site construction order, carefully investigated safety hazards, and supervised the effective implementation of safe and civilized construction work. In terms of environmental protection, the project department called on all personnel to actively respond to the tenet of "protecting Erhai Lake," cleaning and disposing of domestic and industrial garbage generated during construction every day, and protecting and restoring the Erhai Lake ecological environment in the construction area to the greatest extent. It was the unity and earnest and pragmatic work style of the project department that continuously promoted the orderly progress of the siphon pipe construction work.

 

 

Dali Third Waterworks Siphon Pipe Construction (Φ820×12 860m)

 

Third Waterworks Siphon Pipe Long-arm Excavator Operation

 

　　After accumulating the construction experience of the previous two projects, the project department was very familiar with the construction of the Third Waterworks siphon pipe. Within just three months, the project department's various tasks, including the fabrication of the pipeline assembly platform, pipeline assembly welding, underwater pipe trench excavation, pipe laying, and stone backfilling, proceeded in an orderly manner, and the construction quality, construction period, progress, safety, and environmental protection work achieved more standardized control and management.

 

　　The biggest hidden danger in water construction is wind and waves. During the construction of the siphon pipes of the three waterworks, the relatively large wind and waves had a significant impact on the construction work. Especially during the construction of the Third Waterworks, due to the large diameter of the pipe, the raging wind and waves repeatedly cracked and broke the pipe supports, the excavated pipe trenches were repeatedly filled, and the positioning piles of the pontoon were repeatedly damaged. However, the project department ultimately adopted effective measures, overcame the adverse effects of wind and waves on the construction, and successfully achieved the predetermined work goals. On May 24, the pipe laying work of the Third Waterworks was successfully completed, indicating that the siphon pipe construction had passed the most difficult moment and ushered in the dawn of victory.

 

　　On June 30, the siphon pipes of the three waterworks were successfully put into operation, comprehensively testing the project department's water construction capabilities. In particular, due to the lack of corresponding water construction budget quotas for siphon pipe construction, more auxiliary measures were adopted during the construction process, the workload was large, and the cost was high. Although this will bring great difficulties to the later settlement work, the continuously accumulated work experience will help us to continuously improve in our future work and calmly cope with similar engineering practices.

 

　　The siphon pipe construction is the second project implemented by the project department in the Dali area, following the "Dali Bai Village Sewage Treatment Project." In May, the project department also implemented the construction task of the eleventh section of the "Dali Three Reservoirs Connected to Erhai Emergency Water Replenishment Project." Currently, the construction of the siphon pipes for the three water plants is basically completed. The project department has overcome many difficulties and accumulated rich construction experience. Under the correct guidance and strong support of the company, the project department will usher in more "firsts." We are also confident that we will continue to make progress, overcome difficulties, and meet challenges. [Six Construction Department/Chu Wenlin]