Seismic Failure Modes and Assessment of Underground Pipelines

Seismic Failure Modes and Assessment of Underground Pipelines

Taiwan is located at the junction of the Eurasian and the Philippine plates in the Pacific Rim seismic zone, where disastrous earthquakes have repeatedly occurred. As a result, Taiwan has a rich geography, with mountains, forests, basins, plains, and bay shores. It also has geological conditions such as alluvium and backfill that are prone to soil liquefaction. When earthquake disasters occur, they are accompanied by immense social shocks and economic losses. For example, a magnitude 6.6 earthquake in the Meinong area of Kaohsiung on February 6, 2016 caused many buildings to collapse and be destroyed in the Tainan area. At the same time, the soil liquefaction caused building subsidence in many places, and many water supplies were also interrupted by water bursts due to the earthquake and the collapse of Weiguan Building. Additionally, natural gas systems are also decompressed to avoid secondary disasters. During the 1999 Chi-Chi earthquake, additional major disasters occurred such as subgrade cracking and lateral shifting due to soil liquefaction, underground pipe rupture and floating, and subsidence along wharves. Few studies have investigated underground pipeline earthquake risk assessment. The seismic design of underground pipelines and their failure modes requires careful evaluation and consideration to avoid disasters. Furthermore, this also enables the assessment of damage and loss caused by an earthquake to the pipeline, which can be used as a reference for disaster prevention, emergency response, or post-disaster recovery.