Effect of Low Temperature on the Undrained Shear Strength of Deep-Sea Clay by Mini-Ball Penetration Tests

Abstract

The technology for in situ testing of the undrained shear strength of deep-sea clay is underdeveloped. Indoor tests remain necessary, and there is a large temperature difference between in situ and laboratory tests. To analyse the effect of temperature on undrained shear strength, in this study the physical characteristics of marine clay samples from the South China Sea were determined, followed by penetration tests by the mini-ball method under low (4 °C) and room (20 °C) temperatures. The results indicated that the clay strength increased by 14.1–30.0% as the temperature decreased from 20 °C to 4 °C, and the strength of the bound water and the viscosity of the free water in the clay sample increased as the temperature decreased, which was the root cause of the increase in the clay strength. Based on the research, it is possible to correct the undrained shear strength values measured in laboratory tests and provide more reasonable parameters for ocean engineering.

Advances in Marine Engineering: Geological Environment and Hazards

“…Gu et al [10] investigated the low-temperature effect on the undrained shear strength of undisturbed marine clay samples from the South China Sea using a full-flow penetrometer. They found that the undrained shear strength at an in situ temperature (4 • C) is bigger than at room temperature (20 • C), which is valuable for offshore geotechnical engineers.…”

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“…The high-quality papers collected in this SI involve many classic and innovative methodologies in this research field, including, but not limited to, analytical and statistical analyses, numerical simulations, laboratory testing, and marine surveys. Specifically, some researchers carried out in situ marine surveys and monitoring [2,3], some implemented discrete element and finite element numerical simulations [4][5][6], some conducted indoor unit tests [7][8][9][10][11][12], some developed laboratory model tests [13,14], and others applied analytical and statistical methods [1,[6][7][8]. These papers represent the state-of-the-art in the latest research concepts, advanced methods, and data that will contribute greatly to the development of the field of marine geological environments and hazards.…”