Super-large diameter shield "Ma Wan" off the production line

On January 18, the super-large diameter (15.53m) mud and water balance shield machine "Ma Wan" was off the production line. The equipment will be used in Shenzhen Ma Wan Cross Sea Tunnel, which is currently the largest diameter shield tunnel in China.

The shield section of Mawan cross-sea passage has a total length of 2,063 meters, and there are many difficulties in construction: "long" -- 50% of the unevenly soft and hard rock strata and 34.15% of the full-section hard rock exist on the pushing line, and the distance between the equipment and the high-strength rock strata is long; "Difficult" -- it is easy to cause the shield machine to float and deviate from the preset track when crossing the complex terrain of the sea bottom, resulting in great tool wear, high risk of tool change and great difficulty in construction; "Deep" -- the undersea tunnel is located at a depth of more than 40 meters, with a maximum water pressure of 5bar and rock strength of 193MPa. "Big" -- the tunnel has a large section and the outer diameter of the segment is 15 meters. The largest submarine shield tunneling equipment in China is adopted, which requires extremely high equipment performance and construction technology.

The equipment the excavation diameter of 15.53 meters, about 140 miles in length, weight of 4650 tons, with normal pressure swing in knife, the knife dish scale, the main drive pressure, double pneumatic pressure system, the function such as residue in efficient screening system, large flow fluid circulation system at the same time, to ensure the shield construction machine rapid advance in the complex formation, can well deal with complex conditions of project risk.

The Mawan cross-sea passage is an amphibious project, which is divided into two parts: ground road and underground road. The tunnel is 6280 meters in length. The underground road is planned to be an urban expressway with six lanes in both directions and a design speed of 80 km/h. After the completion of the project will assume nan shan harbor dredging port freight traffic, both for mom, chiwan bay area and shenzhen bay area passenger transport links, such as sea before implementation of foreign "separation of passenger and cargo transport, to reduce dredging port traffic to sea before the influence of traffic environment, improve the regional road network structure, support the former sea high-end positioning, is of great significance.