China plays host to CFRD event
22 September 2009The first international symposium on rockfill dams is set to take place in China during October.
Rockfill dams are considered to be the most popular type of dam in the world, with concrete face rockfill dams (CFRDs) being described as the most competitive, offering the greatest potential from an engineering perspective.
In order to summarise the experience of such dams, further promote the technical progress of CFRDs and share expertise on the design, construction and performance of high rockfill dams, a new international meeting has been organised.
The Chinese Committee on Large dams (CHINCOLD) and the Brazilian Committee on Large Dams (CBDB) have agreed to take turns to jointly sponsor international symposiums on rockfill dams in China and Brazil.
The first symposium will be held in China from 18-20 October 2009 in Chengdu, Sichuan Province. Topics to be covered include operation, performance and safety monitoring; hydraulic issues and river diversions; super high CFRDs and clay core rockfill dams (H>200 m); and seismic analysis.
During the development of dam construction many rockfill dams, including CFRDs, have been built and are operating well; inspiring great confidence in this type of structure. Such projects can be considered as milestone schemes and CHINCOLD and CBDB believe they deserve to be acknowledged. Consequently the organising committee of the symposium has invited experts from the pioneer and leading countries of rockfill dams to recommend projects as potential candidates of International Milestone Rockfill Dam Projects. Nominated projects need to demonstrate innovative progress in design, construction or rehabilitation. At the same time the project should work well with good performance.
A special celebration to award the representatives (the owner, designer, construction contractor, etc) of accepted projects will be held during the Chinese symposium. Certificates will be issued by the president of icold, the president of CHINCOLD and chairman of CBDB.
Chinese experience
Both Brazil and China are very active in building rockfill dams. Taking CFRDs as an example, based on the research achievements and practices in construction techniques, seismic safety analysis, dam materials using soft rock, as well as construction methods in cold and high altitude areas, the development of CFRDs has accelerated in China over recent years.
There are 190 CFRDs higher than 30m in China, which are either completed or under construction. These include:
• Shuibuya (233m).
• Jiangpinghe (221m).
• Sanbanxi (186m).
• Hongjiadu (179.5m).
• Tankeng (162m).
• Zipingpu (156m).
Shuibuya is located on the upper reaches of the Minjiang river and is the highest CFRD to be completed in the world. It is 233m high with a crest length of 660m, and a total volume of 15.64X106 m3. The installed capacity of the Shuibuya powerplant is 1600MW, with an annual output estimated at 3.92GWh. The project has a powerful regulating capacity, with a normal pool level at el.400m and a reservoir capacity of 4.58 X109 m3.
Sichuan Province is one of the most important hydro bases in China with rich hydro resources. Many projects have been built or under construction in this area. According to the CHINCOLD dam register there are about 278 large dams (over 30m) in Sichuan.
Zipingpu CFRD in Sichuan Province is the first dam over 100m to have experienced and remained safe through a magnitude 8 earthquake which struck Wenchuan County on 12 May 2008. More than 69,000 people died in the event. No dams were breached in the quake-hit region and any secondary disasters were avoided due to the structural integrity of the dams.
A special technical tour to visit projects in the Wenchan earthquake stricken area will be made before the start of the Chinese symposium. Two study tours are also taking place afterwards. Some of the projects to be included are detailed below:
• Three Gorges project located in Yichang, one of the biggest hydropower complex projects in the world, ranks as the key project for the improvement and development of the Yangtze river. The dam is located in Xilingxia gorge, one of the three gorges of the river, which will control a drainage area of 1M km2, with an average annual runoff of 451B m3. The open valley at the dam site, with hard granite as the bedrock, has provided favourable topographical and geological conditions for dam construction.
• Maopingxi asphalt concrete rockfill dam. The Maopingxi protective dam is the first rockfill dam with asphalt concrete core which is 104m high. Over 20,000m3 of asphalt concrete was placed during phase I construction.
• Shapai RCC dam was the highest RCC arch dam in the world built at the end of the 20th century. It is 132m high, with a dam crest elevation of 1867.5m, normal water level of 1866m, total reservoir capacity of 18X106m3 and installed capacity of 36MW. The site of Shapai arch dam is about 36km away from the epicenter of the Wenchuan earthquake. No damage was detected after the earthquake.
• Pubugou core rockfill dam is a large dam on the Dadu river, a tributary of the Yangtze river in Sichuan Province. The total generating capacity of the project is 3300MW. Construction started in March 2004 and is scheduled for completion in 2010.
• Yele rockfill dam has an asphalt concrete core and is part of Yele hydropower project in Sichuan. The dam foundation is situated on complex geological conditions and contributed to various challenges which had to be overcome during construction. With an average altitude of 2700m, a winter period of six to seven months, the annual construction period only lasted for about 120 days.
For more information log onto www.chincold.org.cn
Don't miss the October issue of International Water Power & Dam Construction, which will include details of 10 of the world's tallest CFRDs.
