Shanghai's rail authority said yesterday that last week's cave in at the construction site of a cross-river subway tunnel will not necessarily lead to the rail route being changed.

Liu Gang, a public-relations officer of the Shanghai Metro Construction Corp, said a specific restoration plan will be worked out within a month and that the damaged part of the tunnel will "hopefully" be repaired in the "near future."

He added: "A general sketch of the plan will be set out in the next few days."

The metro line will link the west of Shanghai city center with Pudong district across the Huangpu River. Construction began in 2001 and trials are scheduled to begin on the line in 2005.

The accident-hit part of the tunnel is located at a depth of nearly 30 meters beneath the ground. It has been sealed with huge reinforced concrete walls before any further repair work will start on it.

Water has also been poured into the sealed part of the tunnel in a bid to maintain the balance of underground water pressure between the inside and outside of the tube to prevent further ground subsidence.

The tunnel cave in took place on Tuesday last week. It caused drifting sand to pour in, which experts have described as one of the most formidable threats in any underground engineering project. This led to a wide area of land subsiding.

One building in the area collapsed and several others tilted in a chain reaction. Part of a floodwall along the Huangpu River also broke. No casualties were reported, however.

Residents in the area said their everyday lives have not been affected very much.

(China Daily July 9, 2003)