Earthquake effect on buried pipes

Due to the damage to the superstructures caused by the earthquakes that occurred in recent years, research on the behavior and design of superstructures under dynamic loads has increased. However, when we look at the literature, studies on infrastructure systems under dynamic loads are less compared to studies on superstructure systems. In this respect, the design of infrastructure systems is as important as the design of superstructures under dynamic loads in terms of civil engineering. Buried pipelines are indispensable engineering structures for the continuity of rural and especially urban life. While drinking water and sewer lines were the first examples of buried pipelines in the past, today there are lines such as oil, natural gas, electricity, telephone and drainage in addition to drinking water and sewer lines. Due to the widespread use of buried pipelines today, the design and manufacture of buried pipes is very important in natural disasters such as earthquakes, especially in terms of the sustainability of city life. If the behavior of buried pipes with different material properties in different soil conditions under earthquake loads is known, the design and applicability of buried pipelines will be much easier. In this study, three different soil models, namely Mohr-Coulomb (MC), Hardening Soil (HS) and Hardening Soil Small Strain (HSSS), two different pipe types, concrete (rigid) and PVC (flexible), three different pipe lining materials with 80%, 90% and 100% relative density and two different ground water levels were modeled in a single soil profile by using Plaxis 2D finite element program and analyzed under earthquake load. In this scope, the analysis results were compared to see the effect of soil model, pipe type, pipe liner material and groundwater level on the behavior of buried pipes under dynamic load. As a result, it has been observed that buried pipes have more displacement and are exposed to more loads in dynamic conditions. It has been concluded that the results of the analysis made with the HS soil model are closer to reality. It has been observed that the pipe type has no effect on the displacement, but the pipe is exposed to more loads with increasing rigidity. In addition, it has been observed that when the groundwater level is lower than the bottom of the pipe, displacements are less.