Liquefaction Countermeasure Technique by Using Logs for Carbon Storage Against Global Warming

Global warming is one of the most serious problems which faced by civil engineers in this century. Because a wood can store carbon within itself, the utilization of wood in the construction projects may contribute to the mitigation of global warming. The technique of ground improvement by installing logs into loose sand layer as a countermeasure against soil liquefaction was proposed in this study. The logs had been used as pile foundation until 1950\u27s in Japan. However, as the wood has high possibility of a decrease in strength by decay, the utilization of wood become minority in the construction projects. First, since a lot of former wooden piles were found at the riverbed of the Asuwa River in Japan in 2005, the soundness of wood was evaluated. From the test results, it was confirmed that the level of decay was extremely low and the compression strength exceeded the allowable stress of wood pile, though they were buried under the riverbed for 59 years. Second, small scale shaking table tests in a 1-g gravity field were carried out using a composite ground which was made of loose saturated sand layer and the improved ground by piling with logs. It was clarified that the logs installed in liquefiable soil layer could increase the resistance of ground against liquefaction and decrease the settlement of structure

Inclination of houses induced by liquefaction in the 2018 Hokkaido Iburi-tobu earthquake, Japan

金沢大学理工研究域地球社会基盤学系BackgroundOn September 6th, 2018, at 3:07 local time, a strong earthquake of magnitude Mw = 6.6 struck the east Iburi region in Hokkaido, Japan. Many serious damages such as landslide, liquefaction and collapse of houses occurred from this earthquake. Liquefaction caused road deformation and inclination of houses in Sapporo city, Hokkaido. In order to understand the damage caused by the earthquake, and find a solution to mitigate the liquefaction-induced damage in Sapporo city, a preliminary investigation of the 2018 Hokkaido Iburi-tobu earthquake was conducted from 18 to 20 September 2018.ResultsThe damages to the houses at Satozuka town and Utsukushigaoka town in Sapporo city are focused on. The damage at Satozuka was so enormous that the residents could not continue to live in their houses. Although the inclination of houses can be seen by visual inspection at Satozuka, there were few houses where the inclination can be judged visually at Utsukushigaoka. Therefore we did a field survey of inclined houses by using a digital angle meter at Utsukushigaoka.ConclusionsThe inclination of 57 houses at Utsukushigaoka was measured, and the maximum value and direction of inclination are shown on the map. The houses located at the reclaimed land of the former river and former valley plain were inclined. Therefore, the old terrain greatly affected to the inclination of houses. These liquefaction-induced damage occurred in the same area where liquefaction occurred during the 2003 Tokachi-oki earthquake

Structural damage to houses and buildings induced by liquefaction in the 2016 Kumamoto Earthquake, Japan

金沢大学理工研究域地球社会基盤学系BackgroundIn April 2016, Kumamoto City, Japan, and its surroundings were hit by a sequence of strong and devastating earthquakes including two significant events, one on April 14th, 2016, at 21:26 JST (Mw6.2) and the other on April 16th, 2016, at 01:25 JST (Mw7.0). These disasters caused 120 fatalities (including indirect fatalities), 2337 people injured and 177,914 residential houses were damaged. This paper aims to ascertain the damage to residential houses and buildings caused by liquefaction during this earthquake and suggests possible mitigation methods.ResultsField reconnaissance was conducted in the target area on May 27th–30th, 2016. The post-earthquake inclination angle and the tilt direction of 68 affected houses and buildings in the liquefied sites in Kumamoto City were measured by using a laser rangefinder (Leica DISTO D 510). Ground structure and condition were also determined from topographic maps, bore data and the calculated liquefaction resistance factor, FL.ConclusionsBased on this investigation, the inclination angle of the houses in the target area seems to be related to the type of building structure and their foundation as well to the local ground composition. The tilt direction has a tendency to be associated with the location of the nearby river. The results presented could be useful to develop future liquefaction mitigation measures for detached residential houses

Learning lessons from the 2011 Van Earthquake to enhance healthcare surge capacity in Turkey

Historically, Turkey has adopted a reactive approach to natural hazards which resulted in significant losses. However, following the 1999 Kocaeli Earthquake, a more proactive approach has been adopted. This study aims to explore the way this new approach operates on the ground. A multinational and multidisciplinary team conducted a field investigation following the 2011 Van Earthquake to identify lessons to inform healthcare emergency planning in Turkey and elsewhere. The team interviewed selected stakeholders including, healthcare emergency responders, search and rescue services, ambulance services, and health authority representatives, in addition to conducting a focus group. Data were analysed according to an open coding process and SWOT (strength, weakness, opportunity, and threat) analysis. The findings suggest that the approach succeeded in developing a single vision by consolidating official efforts in a more structured way, mobilising many governmental and non-governmental organisations, securing significant amounts of resources including physical and human, and increasing the resilience and flexibility of infrastructure to expand its capacity. However, more attention is required to the development of stronger management procedures and acquisition of further resources

Learning lessons from the 2011 Van Earthquake to enhance healthcare surge capacity in Turkey

Historically, Turkey has adopted a reactive approach to natural hazards which resulted in significant losses. However, following the 1999 Kocaeli Earthquake, a more proactive approach has been adopted. This study aims to explore the way this new approach operates on the ground. A multi-national and multi-disciplinary team conducted a field investigation following the 2011 Van Earthquake to identify lessons to inform healthcare emergency planning in Turkey and elsewhere. The team interviewed selected stakeholders including, healthcare emergency responders, search and rescue services, ambulance services, and health authority representatives, in addition to conducting a focus group. Data were analysed according to an open coding process and SWOT analysis. The findings suggest that the approach succeeded in developing a single vision by consolidating official efforts in a more structured way, mobilising many governmental and non-governmental organisations, securing significant amounts of resources including physical and human, and increasing the resilience and flexibility of infrastructure to expand its capacity. However, more attention is required to the development of stronger management procedures and acquisition of further resources

Proposal of liquefaction countermeasure technique by log piling for residential houses

The Tenth International Symposium on Mitigation of Geo-disasters in Asia Matsue Symposium Place: Shimane Civil Center, Matsue Date: 8 October 2012During the 2011 Great East Japan Earthquake in Japan, extreme liquefaction caused extensive damage to residential houses in the Kanto Plain region with the magnitudes of the settlements and tilts larger than that was observed during past earthquakes. This paper deals with a proposal of technique of ground improvement by installing logs into loose sand layer as a countermeasure against soil liquefaction for the residential houses. Small scale shaking table tests in a 1-g gravity field were carried out using some model grounds. It was clarified that the wooden pile could increase the resistance of ground against liquefaction due to the increase of ground density by piling and the dissipation of excess pore water pressure along the surface of piles. As a result, the magnitude of settlements of the house which was set on the improved ground by piling logs became quite small

Shaking Table Tests on a Deformation Mitigation Method for Existing Road Embankment during Liquefaction by Using Gravel and Geosynthetics

Small scale shaking table tests in a 1-g gravity field were carried out to evaluate effectiveness of a deformation mitigation method for an existing road embankment during liquefaction by using geosynthetics sandwiched between gravel layer and a gabion. The gravel layer could dissipate an excess pore water pressure during liquefaction immediately, and perform as a rigid plate below a slope of embankment. Furthermore, the gabion could confine the slope of embankment and restrain the lateral movement of slope. As a result, these functions could restrain the deformation of embankment, and keep the shape of embankment and flatness of crest

Shaking Table Tests on a Deformation Mitigation Method for Existing Road Embankment during Liquefaction by Using Gravel and Geosynthetics

Small scale shaking table tests in a 1-g gravity field were carried out to evaluate effectiveness of a deformation mitigation method for an existing road embankment during liquefaction by using geosynthetics sandwiched between gravel layer and a gabion. The gravel layer could dissipate an excess pore water pressure during liquefaction immediately, and perform as a rigid plate below a slope of embankment. Furthermore, the gabion could confine the slope of embankment and restrain the lateral movement of slope. As a result, these functions could restrain the deformation of embankment, and keep the shape of embankment and flatness of crest