Recently，China's first earth pressure balance shield machine exported to South America, jointly built by China Railway Construction Heavy Industry and China Railway Construction International Group, was launched in China Railway Construction Heavy Industry.，Present a gift to the National Day。The equipment is 105 meters long.，Excavation diameter 9.8 meters，It will be applied to the first subway project of Chinese enterprises using shield construction in South America.——Lot 1 of Santiago Metro Line 7 Project in Chile。

The total length of Bid Section 1 of Santiago Metro Line 7 Project in Chile is about 7.9 kilometers，The shield machine needs to complete the excavation task of about 6700 meters.。The project underpasses the Mapocho River，Length of underpass: 60m，The bottom of the river is about 10 meters from the top of the tunnel.。The section tunnel of the project mainly passes through the stratum of fine-grained soil.、Silt、Clay、Sand、Gravel、Pumice layer、Volcanic rock formation（Granodiorite）。The minimum turning radius of the line is 250 meters.，The turning ability of the shield machine is required to be high.。

According to the engineering geological characteristics of the project，The R & D team of Railway Construction Heavy Industry has configured a number of independent core key technologies for the shield machine.，The cutterhead has six spokes+Six-panel composite design，The support mode is intermediate support。The cutter head is provided with a hob.、Cutter and edge scraper，Full face excavation of the tunnel，And can realize positive and negative bidirectional rotary slag discharge.，All detachable tools can be changed from the back of the cutterhead。When the shield machine needs to turn，It is adjusted by the stroke difference of each group of propel cylinders.，So that that minimum tur requirement of the line is met。 

It is reported that，Santiago, Chile Metro Line 7 is 26 kilometers long.，The construction period is 6 years.，It is a key project of the Chilean government in recent years.。The line passes through seven urban districts of the capital.，Seven island stations are planned to be built，And construction shafts, etc.。After the completion of the project，It only takes 43 minutes to run the whole line.，The distance between the two terminals can be shortened by 54%Travel time for，Provide fast and convenient travel services for more than 1.36 million residents。