{"id":20,"date":"2026-06-08T15:22:59","date_gmt":"2026-06-08T06:22:59","guid":{"rendered":"https:\/\/e-defense.bosai.go.jp\/geotech\/en\/wpen\/?page_id=20"},"modified":"2026-07-07T12:34:52","modified_gmt":"2026-07-07T03:34:52","slug":"research_details","status":"publish","type":"page","link":"https:\/\/e-defense.bosai.go.jp\/geotech\/en\/research_details\/","title":{"rendered":"Research Details"},"content":{"rendered":"<main>\r\n    <section class=\"second research\">\r\n      <div class=\"bg\">\r\n        <h2>Research Details<\/h2>\r\n      <\/div>\r\n      <div class=\"breadcrumb\">\r\n        <ul>\r\n          <li><a href=\"\/\">Home<\/a><\/li>\r\n          <li class=\"current\">Research Details<\/li>\r\n        <\/ul>\r\n      <\/div>\r\n      <div class=\"inner\">\r\n        <section>\r\n          <h3>Research Details<\/h3>\r\n        <p>Based on <a href=\"background_and_objectives\/\">the background and objectives<\/a>, this study will focus on the following key research content.<\/p>\r\n        <section>\r\n          <h4>Identifying factors affecting post-liquefaction soil properties<\/h4>\r\n          <p>Long-term surveys of soil liquefied in past earthquakes have shown the follows:<br>\r\n            1) The shallow portion of the liquefied layer becomes looser than before liquefaction, while the deeper portion becomes denser;<br>\r\n            2) The properties of liquefied soil recover slowly over time, and it took several months to half a year until the soil properties became stable.<br>\r\n            Furthermore, numerical analysis suggests that the contact forces between soil particles are redistributed between the pre- and post-liquefaction states.<br>\r\n            Based on these results, a hypothesis can be established that the properties of soil after liquefaction are influenced by the post-liquefaction sedimentation process of soil particles\u2014specifically, the redistribution of soil particles and contact forces. Fig. 1 shows a conceptual diagram illustrating the arrangement of soil particles before and after liquefaction.<br>\r\n            The smaller the diameter of soil particles, the slower the rate of sedimentation as they float and settle due to liquefaction. Therefore, soil particles with smaller diameters tend to settle loosely at shallower depths. If a layer with low permeability exists near the ground surface, it is anticipated that high pore water pressure will be maintained for an extended period, slowing the sedimentation rate of soil particles and making them even more likely to settle loosely. Based on this hypothesis, the research plan for the E-Defense experiment and related studies will be established.<\/p>\r\n          <figure class=\"herf\"><img decoding=\"async\" src=\"https:\/\/e-defense.bosai.go.jp\/geotech\/en\/wpen\/wp-content\/themes\/geotech\/assets\/img\/Fig1_RD.png\" alt=\"Fig. 1: Arrangement of soil particles before and after liquefaction\">\r\n            <figcaption>Fig. 1: Arrangement of soil particles before and after liquefaction<\/figcaption>\r\n          <\/figure>\r\n        <\/section>\r\n        <section>\r\n          <h4>Preliminary studies for the E-Defense experiment<\/h4>\r\n          <p>Since the E-Defense experiment is large-scale and requires significant time and resources, preliminary studies\u2014including small- to medium-scale model experiments and numerical analyses\u2014are being conducted to maximize the results. Because the National Research Institute for Earth Science and Disaster Resilience alone has limited resources, these studies are being conducted in collaboration with researchers both domestic and international.<\/p>\r\n        <\/section>\r\n        <section>\r\n          <h4>Large-scale experiments using the E-Defense shake table<\/h4>\r\n          <p>According to plans as of July of fiscal year 2026, large-scale experiments using the E-Defense shake table and the large rectangular soil container shown in Fig. 2 are being planned for fiscal year 2027. After applying seismic motion to induce liquefaction in the soil, the soil will be left undisturbed for 1 to 1.5 months, during which time periodic soil investigations will be conducted to evaluate changes in soil properties following liquefaction and the re-liquefaction strength. \r\n            Subsequently, seismic motion will be applied again to induce re-liquefaction of the soil. Based on an evaluation of the data obtained from the E-Defense experiments, a method for assessing changes in soil properties following liquefaction will be proposed.<br>\r\n            Data obtained from the E-Defense experiment will be released as soon as possible to promote its use by researchers both domestically and internationally. Progress and other updates will be reported on <a href=\"\/geotech\/en\/article_list\/e-defense_experiment\/\">the E-Defense Experiment page<\/a>. In addition, the E-Defense experiment data will be used as reference data to verify preliminary findings and to conduct experiments and numerical analyses that complement the E-Defense experiment. These research efforts will be also introduced on <a href=\"\/geotech\/en\/article_list\/related_studies\/\">the Related Studies page<\/a>.<\/p>\r\n          <figure><img decoding=\"async\" src=\"https:\/\/e-defense.bosai.go.jp\/geotech\/en\/wpen\/wp-content\/themes\/geotech\/assets\/img\/Fig2_RD.jpg\" alt=\"Fig. 2: Large rectangular soil container in E-Defense\">\r\n            <figcaption>Fig. 2: Large rectangular soil container in E-Defense<\/figcaption>\r\n          <\/figure>\r\n        <\/section>\r\n        <section>\r\n          <h4>Hosting a numerical analysis competition<\/h4>\r\n          <p>Regarding the E-Defense Experiment, preparations are in progress to hold an international numerical analysis competition. Through this event, the aim is to contribute to the validation of numerical analysis techniques, the promotion of data utilization, and the enhancement of the research community. Details will be posted on <a href=\"\/geotech\/en\/article_list\/numerica_analysis_competition\/\">the Numerical Analysis Competition page<\/a> as soon as finalized.<\/p>\r\n        <\/section>\r\n        <section>\r\n          <h4>Promotion of related studies<\/h4>\r\n          <p>Whenever a major earthquake occurs, there are reports of ground deformation due to liquefaction, the uplift of buried pipelines, damage to building pile foundations, and significant sand boils causing roads to become submerged. With the aim of accumulating data that will contribute to the development of real-time health monitoring techniques for such damage to the ground, buried pipelines, pile foundations, and evacuation routes, various experiments, numerical analyses, field surveys, and observations are conducted in collaboration with external researchers. Data from related studies will also be released as widely as possible. For details, see <a href=\"\/geotech\/en\/article_list\/related_studies\/\">the Related Studies page<\/a>.<\/p>\r\n        <\/section>\r\n        <section>\r\n          <h4>Building a research network with data sharing as its core<\/h4>\r\n          <p>In recent years, technological development using AI has advanced rapidly, and the importance of experimental data as physical evidence has increased. Furthermore, the open science movement is gaining momentum, and it is anticipated that the public release of research data will become mandatory in the near future. Given these circumstances, it is necessary to consider the ideal approach to strategic data sharing\u2014rather than simply releasing data because it is mandatory. By building an international research network with data sharing as its core, research efficiency and the rate of data accumulation can be improved (Fig. 3). Through this research, discussions on the ideal structure of research networks will be explored with researchers both domestically and internationally, with the goal of constructing a prototype network.<\/p>\r\n          <figure class=\"figure\"><img decoding=\"async\" src=\"https:\/\/e-defense.bosai.go.jp\/geotech\/en\/wpen\/wp-content\/themes\/geotech\/assets\/img\/Fig3_RD.png\" alt=\"Fig. 3: Overview of research network\">\r\n            <figcaption>Fig. 3: Overview of research network<\/figcaption>\r\n          <\/figure>\r\n        <\/section>\r\n        <\/section>\r\n      <\/div>\r\n    <\/section>\r\n  <\/main>","protected":false},"excerpt":{"rendered":"Research Details Home Research Details Research Details Based on the background and objectives, this study wil\u2026","protected":false},"author":3,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"page.php","meta":{"_acf_changed":false,"footnotes":""},"class_list":["post-20","page","type-page","status-publish","hentry"],"acf":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/e-defense.bosai.go.jp\/geotech\/en\/wp-json\/wp\/v2\/pages\/20","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/e-defense.bosai.go.jp\/geotech\/en\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/e-defense.bosai.go.jp\/geotech\/en\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/e-defense.bosai.go.jp\/geotech\/en\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/e-defense.bosai.go.jp\/geotech\/en\/wp-json\/wp\/v2\/comments?post=20"}],"version-history":[{"count":8,"href":"https:\/\/e-defense.bosai.go.jp\/geotech\/en\/wp-json\/wp\/v2\/pages\/20\/revisions"}],"predecessor-version":[{"id":84,"href":"https:\/\/e-defense.bosai.go.jp\/geotech\/en\/wp-json\/wp\/v2\/pages\/20\/revisions\/84"}],"wp:attachment":[{"href":"https:\/\/e-defense.bosai.go.jp\/geotech\/en\/wp-json\/wp\/v2\/media?parent=20"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}