“The bridge design has a tower height of 140 meters and a pile depth of 130 meters. Construction on soft soil carries relatively high risks. The Feiyun River Bridge is the most challenging project, serving as the key project of the Lingkun to Gexiang section of the Ningbo-Taizhou-Wenzhou Expressway duplicate line,” said Jiang Yulong, deputy director of the Wenrui Section Management Office of the Ningbo-Taizhou-Wenzhou Expressway duplicate line. He added that in addition to the long main span, the soft soil characteristics of Wenzhou also pose considerable challenges to the project. It is understood that the controlling project of the Lingkun—Gexiang section of the Ningbo-Taizhou-Wenzhou Expressway duplicate line is expected to have a construction period of 48 months. The bridge has a main span of 380 meters, with the deepest pile foundation of the main span reaching 130 meters and a tower height of 140 meters. It is the cable-stayed bridge with the largest span in Wenzhou. The project involves offshore construction, with a large volume of pile foundation work, a tight schedule, heavy tasks, high technical standards, and significant construction difficulties. The 0-60 meter layer is silt, and below 60 meters is pebble layer. After comprehensive consideration, Ningbo Yitong Construction Co., Ltd., the company undertaking the pile foundation construction, selected two Sunward SWDM36 rotary drilling rigs. With a hole diameter of 2.2 meters, a depth of 98 meters, and 90 meters into the sea, the hole was completed in 7 hours. The rig has stable and superior overall performance, can operate within a 360-degree range, and the auxiliary legs assist in lowering the casing, ensuring construction efficiency and quality. Satisfied with the construction efficiency of the SWDM36 rotary drilling rig, the contractor later purchased another 36 rotary drilling rig to participate in the project. Currently, three SWDM36 rotary drilling rigs are working together on the Feiyun River Bridge. The SWDM36 rotary drilling rig excels in underwater drilling. First, offshore construction requires good balance of the machine, ensuring stability whether climbing slopes or in harsh construction environments, without tipping over. Second, strict control of pile diameter and high verticality ensure the verticality of the hole. Third, in addition to the excellent performance of the machine itself, construction methods are also a safeguard. From machine entry, how to get onto the offshore platform, to perfect pile formation, Sunward technical personnel are on-site to guide and provide reasonable solutions. The SWDM36 rotary drilling rig previously received unanimous praise from the contractor for underwater drilling of 80 meters at the Zijiang Bridge on the Huai-Shao-Heng Railway.