Study on the Deformation Law of Overlying Buried Gas Pipeline by Excavation of Shallow Double Tunnel

Abstract

Relied on the South-to-North water diversion engineering of the Beijing south main channel, analyzed the construction process of the shallow double tunnel beneath the buried gas pipeline by numerical simulation method, discussed the different effects of the buried gas pipeline which were caused by three kinds of hydraulic tunnel excavation plan, and sieved the optimal excavation plan. The results showed that, the maximum settlement and the maximum stress caused by the full-face method is smaller than that caused by the reserved core soil method. While using the same excavation method, double tunnel excavation staggered distance excavation is better than the parallel excavation. The key observation range of pipelines is along the pipe axial direction extending about 3 to 5 times the hole diameter from the center of the pipeline to both side, when the tunnel excavation face is about 3 times the hole diameter before or after the existing pipeline position. When near pipeline 3 times hole diameter scope, the tunnel excavation should adhere to the principles of the footage short, the small disturbance, the frequently observed, and quick supporting. In the end, the safety of transmission gas pipeline is evaluated during the south main channel construction, and some important reference conclusions are given for similar engineering.