Liquefaction Countermeasure Technique by Using Logs
During 2011, Great East Japan Earthquake in Japan, extreme liquefaction caused extensive damage to residential houses in the Kanto Plain region and resulted settlements and tilts larger than that was observed during past earthquakes. This paper deals with
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Abstract During 2011, Great East Japan Earthquake in Japan, extreme liquefaction caused extensive damage to residential houses in the Kanto Plain region and resulted settlements and tilts larger than that was observed during past earthquakes. This paper deals with a proposal of ground improvement technique by installing logs into loose sand layer as a soil liquefaction countermeasure for 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.
Keywords Liquefaction Countermeasure Shaking table test Log Residential house Global warming
M. Yoshida (&) Department of Civil Engineering, Fukui National College of Technology, Geshi, Sabae, Fukui 916-8507, Japan e-mail: [email protected] M. Miyajima School of Environmental Design, College of Science and Engineering, Kanazawa University, Kakuma, Kanazawa, Ishikawa 920-1192, Japan A. Numata Research Institute of Technology, Tobishima Corporation, 5472 Kimagase, Noda, Chiba 270-0222, Japan
F. Wang et al. (eds.), Progress of Geo-Disaster Mitigation Technology in Asia, Environmental Science and Engineering, DOI: 10.1007/978-3-642-29107-4_15, Ó Springer-Verlag Berlin Heidelberg 2013
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1 Introduction Liquefaction is a phenomenon in which the strength and stiffness of a soil is reduced by earthquake shaking and causes a lot of ground failures and structural damage during past earthquakes. Therefore, various liquefaction countermeasure techniques based on soil improvement are proposed to mitigate liquefaction risk by improving the strength, density, and drainage characteristics of the soil. From this point of view, if some piles are installed into loose saturated sand layer, it is expected that the characteristics of ground may be changed as the composite ground of sand and piles. Global warming is one of the most serious problems in this century. Because a tree can store carbon within itself, the utilization of wood in the engineering field for the carbon stock may contribute to the mitigation of global warming. As a way of extending and increasing the usage of wood, the authors consider that wood should be used in the construction project, because a huge amount of materials are used and soft ground scattered in many different locations. However, modern civil engineering constructions seem to be using lesser amount of wood compared to those in the previous times. Therefore, the authors consider that one of the most effective ways to utilize wood is installing the wood into the soft ground as a material for ground reinforcement. Generally, one of the major reasons that affect the reliability of wood is decay and insect damage
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