After extensive problems were discovered in tunnels on part of Japan’s bullet train network (Nov ’99, p6), engineers have now found similar defects in the country’s road tunnels.
The construction ministry has confirmed that water leaks, cracks and cold joints have been found at more than 4500 points in 435 highway tunnels. Serious problems were discovered at 145 locations inside 74 tunnels, representing about 2% of the 3529 road tunnels nationwide. Emergency repairs are being performed to prevent repetition of an incident in June when a section of concrete fell from a tunnel wall, ripping the roof of a speeding bullet train in western Japan.(Aug ’99, p7)
Meanwhile, West Japan Railway Co. (JR West) has taken the unprecedented steps of cancelling services and reshuffling staff in an attempt to overcome the difficulties.
Nine daily bullet train services on the Sanyo Shinkansen line and a local service will be suspended between early November and mid-December to facilitate thorough inspection of all 142 tunnels between Hiroshima Station and Fukuoka’s Hakata Station. The move will affect a total of 342 bullet train services involving an estimated 60 000 passengers.
It is the first time in the past 24 years that Shinkansen services have been cancelled to allow inspections not connected with natural disasters.
Concrete experts had urged the suspension in services, but JR West was at first reluctant because of fears about lost income. JR West earns about $3bn a year from Shinkansen train tickets, 40% of its total revenue. But government pressure forced a rethink, especially after a second incident on October 9, when a 226kg block of concrete fell off the wall of the Kitakyushu Tunnel in Fukuoka Prefecture (Nov ’99, p6). JR West halted bullet train services between Hiroshima and Hakata stations for about 10h to conduct safety checks.
Now JR West will use 49 000 inspectors and technicians to conduct visual and hammer checks throughout the tunnel network. JR West has transferred three executives to the Track and Structures Department of the firm’s railway operations headquarters to oversee inspections.
The rail company also sacked the senior general manager of the operations headquarters and the president of JR West’s Fukuoka branch, although they have been moved elsewhere within JR West. Rail company president, Shojiro Nanya, and the manager of the Track and Structures Department received salary cuts.
The Japanese government has also granted $5.2m to two research institutes to study ways of preventing the deterioration of concrete structures and to find a means to automate tunnel inspections.
