The longest tunnel of Zhengzhou Wanzhou section of Zhengzhou Chongqing high speed railway
On July 26, the xiaosanxia tunnel, the longest tunnel in zhengwan section of Zhengzhou Chongqing high speed railway, was opened, laying a solid foundation for the completion and opening of the whole line.
Zhengzhou Wanzhou section of Zhengzhou Chongqing high speed railway starts from Zhengzhou City, passes Pingdingshan City of Henan Province, Nanyang city of Henan Province and Xiangyang City of Hubei Province to Wanzhou District of Chongqing City, with a design speed of 350 km / h and a length of about 818 km, including 184 km in Chongqing. The Zhengzhou Xiangyang section has been put into operation in December 2019.
Xiaosanxia tunnel is a control project of zhengwan section of Zhengzhou Chongqing high speed railway. It is located at the junction of Fengjie County and Wushan County, Chongqing City, with a total length of 18.9km and a maximum buried depth of 890m.
The geological conditions of xiaosanxia tunnel are complex and belong to grade I high-risk tunnel, so it is very difficult to design and construct the tunnel. The tunnel was designed by China Railway Eryuan Engineering Group Co., Ltd. and constructed by China Railway Tunnel Bureau Group Co., Ltd. and started in February 2017.
The technical personnel of China Railway Eryuan group made advanced geological prediction by means of geological survey and geophysical prospecting, and formulated special design schemes for more than 30 karst caves of various types, such as the design of a bridge with a length of 24 meters and a large karst cave with a longitudinal length of more than 10 meters and a depth of more than 55 meters. China Railway Tunnel Bureau Group has taken measures such as building horizontal guide of horizontal tunnel, grouting water blocking, strengthening tunnel structure support and building sewage treatment station to avoid water pollution caused by construction drainage in the small Three Gorges scenic area, and successfully solved construction problems such as large deformation of soft rock and water inrush from mud.