A safety row hits a Chinese high-speed railway. How serious is the problem?
- State-owned outlet says foundation pillars for a rail bridge in Shandong were shorter than the design length and accuses a construction firm of cutting corners
- But engineering analysts suggest other factors, such as geology, must be considered before assuming the worst
But some industry experts have argued that a more comprehensive investigation is needed to determine the truth. They said shorter-than-design pile lengths were normal in engineering, and that the scandal might be more about a bureaucratic dispute than a safety issue.
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The debate revolves around the construction of the Lai Rong high-speed railway in Shandong province in eastern China. The rail project forms an integral part of the province’s high-speed railway network, spanning 193km (120 miles) and allowing a top train speed of 350km/h.
About 50km of the railway was built by China Construction Eighth Engineering Division (also known as Eighth Division), with construction starting in November 2020. An initial quality examination of the project was completed in late June.
Sanjie Industry Co Ltd of Henan province in central China, one of the subcontractors for that section of the railway line, lodged a report alleging “corruption and violation of the law”.
“They claimed that the Eighth Division was skimping on construction materials, causing quality issues with the piles in some sections of the rail’s foundation,” according to the report by Economic Information Daily.
A journalist from the Economic Information Daily said he had verified the report. He said he compared the construction plans with the subcontractor’s work orders and found inconsistencies in the concrete usage, suggesting that allegations corners had been cut were valid.
Local government authorities in Shandong subsequently sent a team to investigate and promised to publish the results. Because the headquarters of China Construction Eighth Engineering Division are in Shanghai, the Shanghai railway regulatory authority also sent a team to Shandong for an independent investigation.
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An anonymous engineer in the industry said corruption relating to pile length was “almost standard practice”, implying there had been similar situations involving other companies’ work on pile foundations in the past, and that the issue was not unique to this project.
The issue is drawing national attention because the railway pile foundations bear the weight of the entire high-speed railway system; any flaw in their construction could have serious consequences.
Significantly, the incident is playing out in a sector that China prides itself on – infrastructure development.
While the results of the ongoing official investigation are yet to be disclosed, industry insiders note that the media reports might not fully cover the complexity of the issue. Any impact on safety might be limited, and there might be more complex interest disputes behind the report.
The Economic Information Daily report said: “The manager of Sanjie, Xiao Weiguo, stated that while the design requests for the piles to be either 14.5 metres or 15.5 metres [48 or 50 feet] in length, the actual piles were mostly between 10 metres and 13 metres, with over 90 per cent piles short [of the required] length”.
News of the apparent shortfall, regarded as a severe violation of the regulations, was picked up by other media.
However, an experienced and anonymous contractor said it was normal to have a different pile length, saying “actual construction conditions could conflict with the design drawings”.
And on a personal WeChat social media account, former bridge designer Zhang Wei said: “The findings from the official media reports may well be true. It is highly possible that the length of some piles did not meet the designed lengths. However, this potential violation or corruption may not necessarily lead to safety concerns.
“There are three types of piles used in construction: friction piles, end-bearing piles and rock-socketed piles. The first utilises friction between soil and pile foundation to provide support. The other two utilise the support from underground rock formation,” he said.
Before choosing the suitable pile and setting a budget, a geological team is hired to detect the depth of rock formation. Cost considerations mean it is not feasible to drill exploratory boreholes at every pile site. A common guideline for a geologist is to drill holes at intervals, and to estimate the rock depth in between based on experience.
“It’s not possible to know exactly the distribution of rocks in the whole rail line of hundreds of kilometres. Hence, geological teams tend to err on the side of caution and designers add extra length to ensure a safety margin. The design drawings will also note ‘final geological data should be based on on-site drilling data’,” said Zhang.
“The construction team encountered difficulties drilling at the depth of 11 metres. To avoid responsibility, they requested to continue drilling till the design depth of 14.5 metres, but the Eighth Division ordered them to start pouring concrete immediately, causing a disagreement between the two parties,” according to the official Economic Information Daily report.
Zhang said: “It is possible that the drillbit equipped could only penetrate the soil layer and encountered resistance at the rock layer at 11 metres. If the design called for end-bearing piles, which only need to reach the rock layer instead of drilling through it, there would be no need to continue drilling. That also answers why the site supervisor, a third party, did not raise any objections.
“In the construction of end-bearing piles, if the drill reached a depth of 20 metres and hasn’t reached rock layers – even if the design depth is 15 metres – the drilling must continue. The design length given by the design institute is meant to ensure contact with the rock layer, not to be adhered to rigidly.”
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Sanjie’s manager Xiao Weiguo also made further allegations.
The official media report said that “during the conflict, the head of the project with the China Construction Eighth Engineering Division told Xiao: ‘Do what you can, if you can’t, get out’. Following that, the Sanjie company was kicked out of the construction site in the middle of the project”.
National regulations stipulate that if there is a discrepancy between on-site data and the design drawing, new data should be submitted for a redesign. The budget should be revised accordingly, but this can affect profits and the progress of the project.
“There’s a chance that staff at the Eighth Division have concealed the actual rock depth to get extra funding. However, any embezzled funds and safety effects are likely minor,” Zhang said.
The China Construction Eighth Engineering Division, which has more than 50,000 employees and six major branches, is one of the most profitable and experienced companies in the sector. It earned net profits of 12.25 billion yuan (US$1.7 billion) last year, making it the second most profitable subsidiary of China State Construction Engineering Corporation.
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It took part in major projects such as the new Xiamen airport, Changsha airport expansion and the Hannan Yangtze River Bridge in Wuhan.
Official results of an investigation have not been released.
The China Construction Eighth Engineering Division has been contacted for comment and is yet to respond.
