In the world of geotechnical engineering, understanding the behavior of saturated soils under undrained shear conditions is crucial, particularly for the energy sector where foundations and infrastructure often rest on such soils. A recent study published in *Yantu gongcheng xuebao* (Chinese Journal of Geotechnical Engineering) by SONG Erxiang and LIN Shijie from the Department of Civil Engineering at Tsinghua University sheds new light on the inclination angle of undrained shear slip surfaces in saturated soils, potentially reshaping how engineers approach stability analyses and design.
The inclination angle of the slip surface in saturated soils has long been a topic of debate among professionals. SONG and LIN’s research, which combines numerical calculations and theoretical analyses, clarifies that this angle is theoretically 45 degrees at any point under undrained shear. “The slip surface is not necessarily the surface with the highest shear stress ratio,” explains SONG. “For undrained shear of saturated soil, its strength is determined by the effective stress, but deformation should be determined by the constitutive total stress, which is the sum of the effective stress and the excess pore water pressure.”
This distinction is vital for practical applications. In the energy sector, where structures like offshore wind turbines, oil rigs, and pipelines are often built on saturated soils, understanding the true nature of slip surfaces can lead to more accurate stability assessments and safer, more cost-effective designs. “The inclination angle of the slip surface in saturated soil at any point on undrained shear is determined by the friction angle corresponding to the constitutive total stress,” adds LIN. This insight could help engineers optimize their designs, reducing material costs and enhancing structural integrity.
The study also differentiates between the slip surface and the shear band, a topic widely discussed in literature. The authors provide opinions on the likelihood of shear bands appearing in practical engineering scenarios, offering valuable guidance for professionals in the field.
As the energy sector continues to expand into challenging environments, the findings from this research could have significant commercial impacts. By providing a clearer understanding of soil behavior, engineers can make more informed decisions, ultimately leading to more reliable and efficient infrastructure. The research published in *Yantu gongcheng xuebao* (Chinese Journal of Geotechnical Engineering) not only advances academic knowledge but also promises to drive practical innovations in geotechnical engineering, particularly in the energy sector.
This study is a testament to the ongoing efforts to bridge the gap between theoretical research and real-world applications, ensuring that the energy sector can build with confidence on saturated soils. As the industry continues to evolve, such insights will be invaluable in shaping the future of geotechnical engineering.