Challenges to Innovation of Liquefaction Prediction Technology

Abstract

Here, we introduce three innovative challenges to liquefaction prediction technology that the authors have addressed in recent years. The first is an innovation in the test procedure for testing the liquefaction phenomena in element tests. Elemental tests for investigating liquefaction were tests to determine the undrained cyclic shear strength (liquefaction strength). Over the past few decades, liquefaction resistance design has shifted to performance-based design, and there is an increasing demand for soil deformation performance during liquefaction rather than strength tests. A new test method that focuses on residual deformation characteristics is proposed. The second is the innovation of in situ survey methods. In this section, we introduce the challenges of developing a cyclic pressure meter test system. Current in-situ survey technologies are based on standard penetration test (SPT) and cone penetration test (CPT); however, the accuracy of liquefaction prediction has hardly improved in recent decades. Therefore, a fundamental shift in thinking is required. Third, we introduce a technology for detecting the degree of liquefaction from seismic motion without site ground profile information. In today's information society, it has become easier to install seismometers, and technologies using internet of things (IoT) and artificial intelligence (AI) are rapidly developing. When a major earthquake occurs, using the proposed technology, it is possible to instantly predict the extent of liquefaction damage based on earthquake records. In addition, it is possible to detect moderate liquefaction from the records of small and medium earthquakes, making it possible to predict the liquefaction risk in the event of a large earthquake. The challenges introduced here are just beginning and are yet to be resolved. Researchers and engineers involved in geotechnical earthquake engineering are encouraged to address the challenges of developing innovative technologies without being tied to existing ones