On January 21st, Shenzhen's first undersea tunnel, the Mawan undersea tunnel, officially opened. The Mawan tunnel is also the largest diameter undersea shield tunnel project in China. Located in the western part of Qianhai, Shenzhen, the core engine city of the Guangdong-Hong Kong-Macao Greater Bay Area, the Mawan tunnel starts from Yueliangwan Boulevard, crosses Qianhai Bay, and ends at Xixiang Boulevard, with a total length of about 8.05 km.

The Mawan undersea tunnel

The tunnel is divided into two parts: underground and surface. The underground section is a city expressway with six lanes in both directions, designed for a speed of 80 km/h. The surface section is a major urban road, also with six lanes in both directions, designed for a speed of 40 km/h. It includes two undersea shield tunnels, with a maximum excavation diameter of 15.5 meters, making it the leading project in terms of scale among Chinese undersea shield tunnels.

As a key demonstration project for transportation connectivity in the Greater Bay Area, the construction of the Mawan undersea tunnel presented significant challenges. The construction team overcame numerous technical barriers with the help of innovation and intelligent construction techniques. They successfully tackled challenges such as large-scale pit construction in reclaimed land, undersea shield tunnel opposite and parallel intersections with large diameters, and shield tunneling through composite strata with soft upper layers and hard lower layers (with rock uniaxial compressive strength averaging 45 MPa and reaching up to 193 MPa).

The completion of the Mawan tunnel is of great significance. It enhances the external road network structure around Qianhai, Shenzhen. In addition to facilitating freight transportation in the Nanshan Port area, it also serves passenger traffic in regions like Chiwan, Mawan, and Dachen Bay. Moreover, it achieves the separation of passenger and freight traffic, and facilitates transit traffic in the Qianhai area, contributing significantly to the expansion and integration of urban development space, which plays a crucial role in improving the transportation network of the Qianhai area.

Source: Lingnan on the Cloud