Chinese railway builders solve mud-rock problem

Added On July 26, 2017

Construction workers on a Northwest China railway station have had to overcome an unusual problem: building on stone that turns to mud when wet. 
Despite the conundrum, the new station in Lanzhou City formally finished construction on Monday. 
During the building of the new Dongfanghong Square Station, a stop on Lanzhou Rail Transit Line 1, workers found they would be building on top of the notoriously tricky red sandstone. 
SOUNDBITE (CHINESE) YANG HONG, Project manager of Dongfanghong Square Station
"In the construction of the Dongfanghong Square Station, we have encountered the red sandstone geology, a world-class geological problem. The red sandstone geology is widely distributed throughout China, but the red sandstone in Lanzhou is unique and special. The main difficulty is that it is easily turned into mud when mixed with water. This brings great difficulties and interference to the construction, and may cause great troubles to the pit support. The main reason why it is called a geological problem is that there is not yet a particularly effective way to extract the water from the red sandstone."
To conquer the problem, builders dug deep wells to draw water away from the main foundation pit.
They also surrounded the site with a waterproof curtain, and sucked out any remaining water with a vacuum.
The result was a dry, firm base on which they could build the new Dongfanghong Square Station.
SOUNDBITE (CHINESE) YANG HONG, Project manager of Dongfanghong Square Station
"It means that all the difficulties caused by red sandstone have been conquered successfully."