On June 29, 2016, the first shield section, namely, the two-line tunnel section from Yongjianglu Station to Jinjiang Station in the first stage southern extension project of Hangzhou Metro Line 4 was successfully connected to traffic.

The shield section from Yongjianglu Station to Jinjiang Station is located in sand liquefaction strata and at riverside nearby Xintang River. The project was featured by various technical difficulties and high risks. Based on the regional silty-fine sand special strata and the hydrogeological conditions of Xintang River, Powerchina Huadong analyzed and summarized the engineering experience from other companies such as the backward flow of Xintang River between Chengxinglu Station and Civic Centre Station, seepage gushing between Civic Centre Station and Jiangjinlu Station, in combination with the high risk situation of shield reception, and after fully demonstration and research with experts from both Powerchina Huadong and other companies, adopted the scheme of “twin-well tunnel entrance + graded water level lowering + steel sleeve reception”, which was the first time in China, greatly reduced engineering risks and saved project cost as well.

The Project marked a big step for Powerchina Huadong in the design and construction for shield tunnel under complex conditions and in liquefaction strata.