On March 29, the hydraulic grab trenching machine began trenching operations, marking the official start of construction on the No. 1 Shield Conversion Shaft (Changxing Island South Shaft) of Contract 108 of the Chongming Line Phase I project undertaken by Shanghai Tunnel Engineering Co., Ltd. With this, the Chongming Line Phase I project has officially entered the construction stage.

On March 31, the reinforcement cage for the first 48.5-meter-deep diaphragm wall at the No. 1 Shield Conversion Shaft was hoisted and lowered into the trench, marking the start of diaphragm wall construction for the No. 1 Shield Conversion Shaft of Contract 108 of the Chongming Line Phase I project. The foundation pit of the working shaft reaches a depth of 26.05 meters, and the diaphragm wall retaining structure reaches a depth of 48.5 meters. The retaining structure adopts various joint forms such as GXJ and cross steel plates, and the triaxial mixing pile reinforcement at the pit bottom reaches a depth of 32.7 meters.

The Shanghai Rail Transit Chongming Line Phase I project runs from Jinji Road Station to Changxing Island North Shaft (inclusive), along Shenjiang Road—Gaobao Road—Dongjing Road—Yangtze River South Channel Tunnel—Changxing Island Yongwei Road, with a line length of 22.230 km, using underground alignment, of which the South Channel Tunnel is 7.738 km long. It includes 5 underground stations, one Dongjing Road Depot, one intermediate ventilation shaft, and 3 large and small shield conversion sections.