Beijing, July 25 (Youth.cn) - Photo taken in Jinan, Shandong Province on July 24th. A 17.5-meter diameter cutter head of shield machine was put into the well in the tunnel that going through the Yellow River. The "Mountain and River" shield machine is the largest shield machine in the world in terms of diameter with 163 meters' length and 5200 tons' weight. The cutter head of the shield machine is made of one center block and 4 side blocks, whose weight is 387 tons for each. Being one of the largest passage in Jinan city that cross the Yellow River, the tunnel going through the Yellow River is invested and built by Jinan City Construction Group Co., Ltd and co-built by China Railway 14th Bureau Group. After accomplishment, the tunnel will reinforce transportation capacity between areas and support effectively ecological protection and high-quality development of the Yellow River Basin. Photo/VCG