Core Viewpoint - The article highlights the successful installation of a large underwater shield tunneling machine for the Yantai Port West LNG long-distance pipeline project, which is crucial for natural gas transportation in the Shandong and surrounding regions [1][2]. Group 1: Project Overview - The project includes several key components such as the starting shaft, receiving shaft, shield tunnel, and pipeline laying within the tunnel [2]. - The shield machine's installation is described as the most critical and challenging part of the project, with high risk involved [2]. Group 2: Technical Specifications - After assembly and debugging, the shield machine will excavate 1,749 meters underwater, navigating through complex geological conditions including medium sand, silty clay, silt, and gravel [2]. - The project team customized the shield machine with specialized soft soil cutter heads and a gradient distribution alloy tool combination, forming a "super hard dragon tooth matrix" for long-distance excavation in challenging terrains [2]. - Advanced systems such as a high-precision gas-liquid balance system, dual slurry synchronous injection system, and intelligent segment assembly system are integrated into the shield machine to adapt to varying construction environments and high technical standards [2]. Group 3: Strategic Importance - Upon completion, the tunnel will house a high-pressure pipeline with a diameter of 1.219 meters, essential for transporting natural gas from the LNG receiving station to the mainland [2]. - The project is significant for energy security, emergency reserves, and winter supply guarantees for Shandong, the Bohai Rim, and North China [2].