Core Viewpoint - The successful acceptance of the underground section of the Shenzhen Metro Line 8 Phase III project marks the completion of the largest underground excavation tunnel structure currently under construction in China, with plans to open this line within the year, providing direct access to Dapeng for citizens [1][2]. Group 1: Project Overview - The Line 8 Phase III project is a crucial transportation artery for Shenzhen's "Eastward Strategy," stretching approximately 3.7 kilometers from Xiaomeisha Station to Xiyong Station in Dapeng New District [1]. - The project includes one station, one section, and one vehicle depot, specifically Xiyong Station, the section from Xiaomeisha Station to Xiyong Station, and the corresponding entry and exit lines [1]. Group 2: Technical Details - The accepted underground tunnel section is considered the "throat" of the Line 8 Phase III project, characterized by high difficulty and technical complexity [1]. - The tunnel comprises three parts: entry and exit lines, connection lines, and extraction lines, all constructed using the mining method (drilling and blasting) [1]. - The entry and exit line tunnel is particularly complex, measuring approximately 490 meters in length and featuring multiple cross-section transitions, involving 15 different lining types [1]. - The core section of the single-hole three-line tunnel has an excavation span of 23.78 meters, a height of 18.13 meters, and a single-span excavation area of 334.18 square meters, setting a record for the largest cross-section of underground excavation tunnels in China [1][2]. Group 3: Impact and Connectivity - As the first metro line extending to Dapeng New District, Line 8 Phase III is expected to open this year and will connect with existing Metro Line 2 and the first two phases of Line 8, creating a major transportation corridor across Nanshan, Futian, Luohu, and Yantian to Dapeng New District [2]. - This project will significantly enhance daily commuting for residents along the route, alleviate traffic pressure in the eastern region, and provide strong transportation support for the development of tourism in the eastern coastal area, contributing to the establishment of Dapeng New District as a global marine center and a world-class coastal ecological tourism resort [2].