May 30, 2003
As China prepares to begin filling the Three Gorges reservoir on June 1, a senior member of the project inspection team has acknowledged that some of the cracks that were repaired at great expense on the upstream face of the dam have reopened.
Pan Jiazheng, one of China’s top engineers, said that experts who took part in a final inspection of the dam before it starts holding back water have been particularly concerned about several issues around which further studies are needed.
“During the inspection, for example, we found that some of the vertical cracks on the dam that were repaired have reopened, even though we put a great deal of money and effort into the repair work.
“It appears that during the concrete pouring, we put too much emphasis on the goal of achieving a very high degree of strength. But it has turned out that a high degree of strength does not necessarily mean good quality in a concrete dam. We have achieved an unnecessarily high degree of strength and a lot of cracks in the dam by pouring too much concrete and spending a great deal of money.
“I feel that it’s too early to be proud of ourselves, and we have a long way to go. As we enter the third phase of the dam construction, I hope we will do our best to build a first-class project rather than a dam with 10-metre-long cracks!”
The candid remarks by Mr. Pan, who is a member of the prestigious Chinese Academy of Sciences and former vice-director of the Chinese Academy of Engineering, were made in a speech at the closing ceremony of the May 12-21 inspection, and posted on the Web site of the Changjiang Water Resources Commission.
Mr. Pan also warned that the abnormally severe floods expected this summer pose another major challenge. “It’s true that in the decade since we started building the dam, we have experienced many types of floods. But this year’s floods will be really serious. …
“All the structures we have built will be subjected to a big test, since the Yangtze floodwater is famous for its huge volume and velocity and mighty, destructive power. Of course we ought to be well prepared for powerful, disastrous floods. Please, let us never lower our guard in this respect.”
Mr. Pan told fellow Three Gorges inspectors in November that the 39 billion cubic metres of water to be stored in the reservoir, and natural forces such as floods, earthquakes and landslides, will be the project’s “real examiners” and that they will show no mercy.
“They are ready to take their revenge and exploit any mistakes and misjudgments that we make in design, construction, manufacturing and installation, as well as project management,” he said.
Numerous cracks in the dam were discovered in October, 1999, but only revealed in March last year by the popular South Wind Window (Nanfang chuang) magazine, a sister publication of the Guangzhou Daily (Guangzhou Ribao). After visiting the dam, reporter Zhao Shilong wrote that he had seen cracks stretching from top to bottom of the huge concrete structure.
After the problem was brought to light, Lu Youmei, general manager of the Three Gorges Project Development Corp., acknowledged in Three Gorges Project Daily (Sanxia gongcheng bao) that cracks had appeared on the whole upstream face of the 483-metre-long spillway section, and that they extended from 1 metre to 1.25 metres into the dam.
For his part, Zhang Chaoran, chief engineer of the Three Gorges Project Development Corp., said: “This is a normal phenomenon, and cracks such as these can be observed in almost all large dams around the world.” But he also said: “Our problem was that we failed to take the cracks seriously at first. We didn’t think they would develop so quickly or so dramatically, beyond our expectations.”