Guiyang Metro S1 Line Tunnel Underpasses Nanming River

At around 10am on May 6th, the excavation of the left line of the section from Caosi to Jinjiang Road Station on Line S1 of Guiyang Metro was successfully completed.

Due to the complex geological conditions, dense underground municipal pipeline network, complex ground structures, and continuous traffic flow in the Zhongjin section located in the center of Xiaohe City, construction has faced numerous difficulties.It is reported that the Zhongjin section is the most risky underground excavation section along the entire line. 

The surrounding rock of the tunnel in the section is poor, the stability is poor, and the risk points are densely distributed. From passing through the small river level bridge on the side to crossing the Nanming River, the South Second Ring Elevated Bridge, and old factory buildings... these are all major sources of risk.To ensure construction safety, a one-step, one turn excavation method is adopted when passing through a small river flat bridge on the side, followed closely by the secondary lining construction after the initial support is formed. 

In addition, to ensure that the water source of the Nanming River does not seep into the tunnel, the full section curtain grouting process was adopted when crossing the river. However, the construction of the full section grouting method is two-thirds slower than ordinary excavation. If it is a 70 meter tunnel, normal excavation takes one and a half months, while full face grouting construction takes three to four months.

The smooth completion of the excavation on the left side of the Zhongjin section marks the end of the construction risk period, and the civil excavation progress of the entire section has also been completed by 95%, providing convenience for subsequent construction operations of various units to enter the site. In addition, the Zhongjin section will also be the last completed civil construction section of the S1 line, and the excavation completion of the left line of this section also provides a guarantee for the smooth progress of the construction of the entire S1 line.

It is understood that Guiyang Rail Transit S1 Line is a key project in the transportation construction planning of Guizhou Province and Guiyang City. It starts from Zaojiaoba in Gui'an New District and ends at Wangchengpo in Nanming District. It spans across Gui'an New District, Huaxi District, Economic Development Zone, and Nanming District, with a total length of 30.32 kilometers and 13 stations. It is an important passage from Gui'an New District to the main urban area.