Investigation on the behavior of frozen silty clay subjected to monotonic and cyclic triaxial loading

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RESEARCH PAPER

Investigation on the behavior of frozen silty clay subjected to monotonic and cyclic triaxial loading Xiangtian Xu1 • Qionglin Li2 • Guofang Xu3 Received: 15 November 2018 / Accepted: 30 May 2019 Ó Springer-Verlag GmbH Germany, part of Springer Nature 2019

Abstract This paper aims to assess the characteristics of the deformation and strength behavior of frozen soils at different temperatures under monotonic and cyclic triaxial conditions. The deformation and failure patterns of the specimens change from ductility to brittleness with decreasing temperatures under both monotonic and cyclic loadings. The development of axial strain and stiffness with increasing number of cycles for the soils under cyclic loading is presented and analyzed in detail. A collapse behavior in strength and stiffness is observed in tests of frozen soils at - 5 °C, - 7 °C and - 9 °C. The difference in frictional sliding between the samples with high ductility and those with high brittleness is attributed to the different patterns of deformation and failure. The dynamic modulus is plotted versus axial strain, and the state where the stiffness begins to decrease is employed as the criterion of cyclic failure. The proposed criterion of cyclic failure is verified to be more suitable for frozen soils with high brittleness and seems to be consistent with the peak strength under monotonic loading. Finally, the cyclic stress ratios are plotted against the number of cycles up to this failure criterion, and the effect of temperatures on cyclic strength is evaluated. Keywords Cyclic strength  Deformation mechanism  Frozen soils  Stiffness  Triaxial test

1 Introduction In recent years, an increasing number of construction projects are being carried out throughout the cold regions of the world, and the effective design of foundations for stable structures in cold regions requires detailed knowledge of the strength and deformation characteristics of frozen soil and the influence of temperature on its behavior [6, 21, 25, 26]. In addition, the technique of artificial ground freezing is often used as a construction aid to & Qionglin Li [email protected] 1

Institute of Transportation, Inner Mongolia University, Hohhot 010070, People’s Republic of China

2

Key Laboratory of Earthquake Engineering and Engineering Vibration, Institute of Engineering Mechanics, China Earthquake Administration, Harbin 150080, People’s Republic of China

3

State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, People’s Republic of China

control groundwater or provide temporary support for excavations, tunnels and mineshafts [9, 10, 13, 33]. However, the greater use of such a construction aid is limited due to the lack of detailed understanding and accurate modeling of the behavior of frozen soils under different loading and temperature conditions. Therefore, there is an ongoing demand for the study of the mechanical b

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