At Chanwan North Station, an important node of Shenzhen Urban Rail Transit Line 15, the construction of its retaining structure has entered the final stage. The site presents a busy yet orderly scene, with multiple Jintai double-wheel milling machines, grabs and other large equipment roaring in operation, jointly painting a vigorous and well-organized construction picture.

Stratigraphy at Chanwan North Station: above 15-18m is fill soil, backfilled stone, clay layer, and sand layer. From 15-38.5m is strongly to moderately to slightly weathered granite, with the hardest around 80 MPa. The design specifications of the diaphragm wall are strict: the trench width reaches 1 meter, the trench length ranges from 5m to 7m, and the construction depth is 30m to 38.5m.

Due to the tight schedule and heavy tasks of this project, the project department made a comprehensive consideration and unanimously decided to adopt the currently prevalent industry "drilling-grabbing-milling" combined process for construction, ensuring the high-quality completion of the diaphragm wall. Through the construction using the "drilling-grabbing-milling" combined process, the construction efficiency of the double-wheel milling machine was significantly improved. With the assistance of rotary drilling for pilot holes, the construction speed of the double-wheel milling machine can reach 1.5m to 2m per hour, a significant efficiency improvement compared with 70cm/h to 80cm/h without pilot holes. The application of this technology not only shortened the construction period but also effectively reduced construction costs, fully demonstrating that the construction team has rich construction experience and strong technical strength, fully consistent with the project's high standards.

It is worth mentioning that all diaphragm wall products on site are of the Jintai brand, among which 3 double-wheel milling machines (two SX40A and one SX50C) have been in continuous construction on site for as long as 5 months, fully demonstrating the stability and durability of the equipment. Throughout the entire construction process, these machines have maintained efficient and stable operation, making great contributions to the smooth progress of the project.

At present, the diaphragm wall construction site has been divided into three construction zones. Among them, Zone 1 has completed 61 diaphragm wall panels with 8 remaining, and Zone 3 has also smoothly completed 32 with 2 remaining. The two zones have completed a total of 93 diaphragm wall panels, achieving remarkable phased results. Meanwhile, 12 diaphragm wall panels in Zone 2 are still under intensive construction and are expected to be fully completed before September 2024.

With the continuous advancement of construction, the building of Shenzhen Urban Rail Transit Line 15 is also steadily moving forward. The smooth construction of the retaining structure at Chanwan North Station not only lays a solid foundation for the follow-up work of the entire project, but also demonstrates to the general public the speed and passion of Shenzhen's rail transit construction. We look forward to the early completion and opening of this important transportation project, injecting new vitality into Shenzhen's transportation undertaking.