In earthquake-prone regions around the world, soil liquefaction remains one of the most daunting geological hazards threatening the stability of urban infrastructure. This phenomenon, characterized by a sudden loss of soil stiffness and shear strength under cyclic loading, can lead to catastrophic ground failures and structural damages. Loose, moderately granular sandy soils, commonly found in coastal and riverside urban areas, are particularly susceptible to this risk. In response to this pressing challenge, recent advances in geotechnical engineering have focused on not only mitigating liquefaction hazards but also refining the methods used to evaluate soil resistance. Pioneering research from Japan, led by Professor Shinya Inazumi of Shibaura Institute of Technology (SIT), introduces a transformative approach in this arena through the development of a strain-controlled cyclic triaxial testing methodology combined with eco-friendly chemical grouting to enhance liquefaction resistance.
Traditional evaluation of soil liquefaction resistance predominantly relies on stress-controlled cyclic triaxial tests, wherein the soil specimen is subjected to cyclic stresses to mimic earthquake-induced forces. However, these conventional methods often produce inconsistent results and tend to overestimate the soil’s capacity to resist liquefaction. Such discrepancies pose a significant challenge for engineers and city planners tasked with seismic risk management. Moreover, with sustainability becoming a critical consideration in modern engineering practices, there is a growing demand for environmentally friendly solutions that reduce the ecological footprint of soil improvement techniques. Addressing these concerns, Professor Inazumi’s team has embarked on a dual-front innovation by enhancing both the evaluation procedures and the grouting materials used for soil stabilization.
The cornerstone of this groundbreaking study is a novel strain-controlled cyclic triaxial test, meticulously designed to simulate realistic seismic deformations by maintaining a constant double-amplitude axial strain of five percent. This methodological shift from stress control to strain control enables a more accurate replication of the soil’s dynamic response under earthquake loading. Crucially, the strain-control approach reduces the dependency on multiple specimens, streamlining the testing process while delivering reproducible, reliable data. This innovation is particularly significant as it aligns well with energy-based evaluation parameters, a modern framework gaining traction for performance-based seismic design.
Complementing this testing advance, the research explores the use of a sustainable chemical grouting solution made from colloidal silica combined with geothermal-recycled sodium silicate. Notably, this formulation dramatically cuts down carbon dioxide emissions associated with production by nearly 60% compared to conventional grouting materials. The team tested three different concentrations—6%, 8%, and 10% colloidal silica—to analyze their effects on liquefaction resistance. Findings confirmed that higher colloidal silica concentrations significantly improve soil strength and stability under cyclic loading, with the 10% solution outperforming others in mitigating liquefaction potential.
Integrated within the study is an innovative application of energy-based criteria to evaluate soil liquefaction resistance. By analyzing the cumulative dissipated energy during cyclic loading, Inazumi’s team demonstrated that this metric serves as a reliable indicator of soil behavior and failure potential, surpassing traditional pore pressure and strain-based measures. The researchers also determined a linear correlation between dissipated energy and the liquefaction resistance ratio (R_L20, 5%), which lays the foundation for calibrating these strain-controlled test results with existing stress-based design charts. This integration promises to refine seismic resilience strategies worldwide by offering a more precise and unified framework for measuring liquefaction resistance.
One of the most compelling advantages of this new method is its capacity to contribute to cost savings in ground improvement projects. The reduced requirement for multiple testing specimens enables faster assessments without compromising result accuracy, which is a significant boon for large-scale engineering applications. Furthermore, the reproducibility of results ensures that civil engineers have dependable data to base their design decisions on, improving the safety margins for structures in seismically active zones. Inazumi emphasizes that by embedding these findings into mainstream seismic design frameworks, urban centers can achieve safer, more resilient development patterns with an emphasis on sustainability.
The practical implications of this research extend far beyond laboratory settings. The environmentally benign nature of the colloidal silica grout makes it particularly well-suited for use in waterfront and marine environments, where protecting ecological integrity is paramount. It also addresses a crucial concern related to ground improvement—minimizing vibrations during soil treatment—a factor especially important in densely populated urban areas where excessive disturbance can disrupt daily life and even compromise adjacent structures. Consequently, this approach holds promise for retrofitting existing infrastructure such as schools, hospitals, residential complexes, and seawalls, thereby enhancing community resilience against earthquake risks.
Professor Inazumi and his colleagues also underscore the technique’s potential to prevent lateral spreading of loose, sandy soils during seismic events. Lateral spreading is a common and destructive consequence of liquefaction, often leading to ground displacement and infrastructure failures. By reinforcing the soil matrix through chemical grouting and accurately evaluating its resistance with the proposed strain-control testing, engineers can design more effective countermeasures to stabilize susceptible terrains. This synergistic combination of testing and treatment techniques paves the way for performance-oriented ground improvement designs tailored to specific seismic scenarios.
In a global context, adoption of this strain-controlled testing protocol and the accompanying eco-friendly grouting materials could revolutionize soil liquefaction assessment and mitigation. Regions such as Japan and California, known for their seismic vulnerability, stand to benefit immensely from incorporating these advancements into their engineering standards and construction guidelines. By facilitating precise, reproducible evaluation and promoting sustainable ground treatment options, the research aligns with international efforts to enhance earthquake preparedness, minimize human casualties, and reduce economic losses caused by ground failures.
Looking ahead, the versatility of the strain-controlled cyclic triaxial method invites further exploration into its applicability across various soil types and differing grouting substances. This adaptability promises to extend the technique’s utility beyond sandy soils to clays, silts, and mixed soil matrices, broadening its impact. Additionally, ongoing research could refine testing protocols to accommodate complex loading conditions reflective of real-world earthquake motions, thereby deepening understanding of soil-structure interactions under seismic stress.
Fundamentally, the integration of energy-based evaluation methods marks a paradigm shift in geotechnical earthquake engineering. This approach supports performance-based design philosophies that prioritize resilience and safety through quantifiable, energy-centric metrics. By connecting laboratory insights to engineering practice, the work led by Professor Inazumi embodies the future of sustainable urban development in earthquake-prone areas, leveraging both cutting-edge technology and environmentally conscious materials.
The findings presented in this study not only enrich the scientific understanding of soil liquefaction mechanics but also provide practical tools for engineers and policymakers engaged in earthquake risk reduction. The strain-controlled cyclic triaxial test coupled with environmentally sound chemical grouting offers a cost-effective, scientifically robust, and ecologically responsible solution—a vital stride forward in safeguarding the urban landscapes of tomorrow.
Subject of Research: Soil liquefaction resistance evaluation using cyclic triaxial tests on chemically grouted sand.
Article Title: Evaluation of liquefaction resistance in chemically grouted sand using cyclic triaxial tests.
News Publication Date: September 1, 2025.
References: DOI: 10.1016/j.rineng.2025.106875
Image Credits: Professor Shinya Inazumi from Shibaura Institute of Technology, Japan.
Keywords
Engineering, Environmental sciences, Energy, Earth sciences, Nonrenewable resources, Technology, Construction techniques, Civil engineering, Environmental health, Soils
