Recently, with the successful lifting and installation of the reinforcement cage for the last diaphragm wall panel, the retaining structure west of Guadingjiao in the Zhuhai Tunnel Project TJ1 Section was successfully closed, marking new phased progress in the project's construction and also meaning that Jintai's domestically produced dual-wheel trench cutter has established another benchmark site in Zhuhai, an important node city in the Guangdong-Hong Kong-Macao Greater Bay Area (with dense, hard rock strength of up to over 150 MPa).

The diaphragm wall retaining structure of the Zhuhai Tunnel Project TJ1 Section is located on the west side of the Guadingjiao mountain, close to the estuary of the Xijiang River. The geological conditions are complex: the upper part consists of fluid-plastic silt, with interbedded silty fine sand layers that are prone to hole collapse; the lower bedrock is moderately and slightly weathered granite, with rock surface slopes reaching a maximum gradient of 45°, rock strength of up to over 150 MPa, and numerous spherical weathered granite boulders. This is a typical coastal geological structure with soft upper layers and hard lower layers. The maximum rock-socketed depth of the diaphragm wall reaches 13 m, presenting various technical challenges such as deviation during trenching, difficult penetration, and trench wall collapse. The construction difficulty is at an "expert" level among similar domestic projects.

Since the start of construction, the project team has continued to overcome difficulties. In response to the geological characteristics and construction challenges, through analysis and testing, a combined construction method of rotary drilling for pilot holes and trench cutter excavation was finally adopted, with two Jintai dual-wheel trench cutters and two Jintai rotary drilling rigs deployed as the main trenching equipment. Despite various difficulties and unexpected situations during construction, through the joint efforts of the project team and Shanghai Jintai, the diaphragm wall construction task was completed on schedule and with quality, receiving unanimous praise from the general contractor, supervision unit, and others. At the same time, this diaphragm wall project was successfully selected as one of the second batch of provincial construction industry new technology application demonstration projects in 2021 by the Department of Housing and Urban-Rural Development of Guangdong Province.