The left line of the Wangjiazhai Tunnel, a critical part of China’s Lincang-Qingshuihe Expressway (Linqing Expressway) in Yunnan Province, was completed last month.
The project is being undertaken by China Railway Tunnel Group.
Construction of the challenging 8km left line began in March 2018.
The tunnel’s geological conditions include tertiary water-rich semi-consolidated rock, characterised by poor cementation, extremely soft rock, high saturation, desiccation cracking, poor water stability, and a high risk of disturbances causing sand collapses, mud outbursts, and soil flow.
The most challenging section was the 2.3km geological zone on the Linxiang side, where the company said tunnelling felt “akin to digging through a sponge”.
