地铁盾构机对大多数人来说,是一个模糊的概念。在北京、上海、天津、沈阳等地,人们隔着高高的围挡板偶尔能看到一个个被帆布罩着的庞然大物,却很少有人见到它到底是什么样子。在天津著名商业街金街,地面上人流熙熙攘 Metro shield machine for most people, is a vague concept. In Beijing, Shanghai, Tianjin and Shenyang, people sometimes see huge monsters covered in canvas covered with tall baffles, but few see exactly what it looks like. Golden Street in Tianjin, a famous commercial street, the bustling flow of people on the ground