Input earthquake loads on plaxis 2d youtube

After the 2011 Tohoku earthquake, the Japanese government started to show interest in new effective and inexpensive mitigation methods that could prevent damage to existing lifelines in the future. In the case of a large pipeline network, the application of these methods can be time-consuming and expensive. One of the problems of these mitigation methods is that the enhanced backfill has to be applied in a larger portion of the pipeline system. The success of these methods was partially confirmed during the Chuetsu Offshore earthquake that occurred in 2007. The old backfill is excavated and replaced with improved soil. The mitigation method derived by different authors suggests an improvement of the backfill by soil compaction and cement mixing. The soil loses its shear strength and the pipeline tends to float. During liquefaction, excess pore water pressure is generated, and the effective stresses are reduced drastically. When static, the shear strength and the weight of the soil prevent the flotation of the pipelines. The buoyant force affects them because their unit weight (0в™і9вЂ‰g/cm 3) is lower than that of the surrounding liquefied soil. Despite being covered and protected by the surrounding soil, pipelines are subject to important uplift in the liquefied soil.

In the past two decades, various authors have studied the problem of liquefaction-induced uplift of pipelines ( Koseki et al., 1998). As shown in Figure 1, the uplifting process can be so substantial that the pipelines are eventually uplifted above the ground surface. As soon as the soil liquefies, all the embedded structures start to float in the liquefied soil and the lighter and shallower embedded pipelines tend to move upwards. Several pipelines that were installed in this area were permanently deformed and uplifted because of the buoyancy force acting on them. Reclaimed land is considered to be susceptible to liquefaction during seismic events ( Bhattacharya et al., 2011). This area of the city is characterised for being expanded on reclaimed land. Many of the pipeline damages were observed near Tokyo Bay. These damages caused permanent deformations to the pipelines and interrupted their serviceability for extended periods of time. The depth of embedment of these pipelines varied from 0в™µ to 1вЂ‰m, and, therefore, they were categorised as shallow embedded pipelines. Figure 1 shows how the original design inclination of the pipeline was altered, and as consequence, an entire water supply network was compromised. This earthquake, also called the Great East Japan earthquake, was the most powerful earthquake in the history of the nation.ДЄmong the infrastructure damaged by the Tohoku earthquake were water supply pipelines. The earthquake moment magnitude M w was 9в™°, and the epicentre was 70вЂ‰km east of the Oshika Peninsula at an underwater depth of 30вЂ‰km ( Mimura et al., 2011). Although the Japanese government is investing enormous effort for the seismic safety of structures and the development of new mitigation methods, the authorities were caught off guard on 11 March 2011, when the Tohoku earthquake struck the island of Honshu. Since Japan is a highly populated and infrastructurally advanced country, the potential numbers of fatalities and material costs provoked by an earthquake can be extremely high compared with those in other countries. These are the most meaningful and active plate boundaries on the planet. The archipelago is located on the Pacific Ring of Fire and precisely between the Eurasian Plate, the Pacific Plate and the Philippine Plate.

In the past century, Japan was struck by more than 40 earthquakes with a moment magnitude higher than 7.

Historically, Japan is well known for being one of the most active seismic countries in the world.

Input earthquake loads on plaxis 2d youtube