Journal of Changjiang River Scientific Research Institute ›› 2014, Vol. 31 ›› Issue (5): 52-55.DOI: 10.3969/j.issn.1001-5485.2014.05.011

• ROCKSOIL ENGINEERING • Previous Articles     Next Articles

Experimental Study on the Softening of Saturated Clay of Zhuhai Tunnel under Cyclic Loading

SUN Yang-guang1,2,GAO Yu-feng1,2,LIU Jian-min3,CAO Jiu-ting1,4,HUANG Si-jie1,2   

  1. 1.Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering, Hohai University, Nanjing 210098, China;
    2.Research Institute of Geotechnical Engineering, Hohai University, Nanjing 210098, China;
    3.Shandong Earthquake Engineering Research Institute, Jinan 250021,China;
    4.Institute of Engineering Safety and Disaster Prevention, Hohai University ,Nanjing 210098,China
  • Received:2013-08-30 Revised:2014-05-12 Published:2014-05-12 Online:2014-05-12

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Abstract: To research the softening of clay under cyclic loading, cyclic triaxial tests with stress control were carried out on the normally consolidated saturated silty clay and mucky clay of Zhuhai tunnel. According to the definition of degradation index, the curve of clay’s degradation index was obtained. The development of secant shear modulus in each unload-reload loop was analyzed, and the influence of dynamic stress on the softening of clay was investigated. Results indicated that test sample had critical yield strain εp in every cycle and the degradation of stiffness was obvious when the cycle number was small. But with the increase of cycle number, the stiffness degradation reduced or even did not occur. Compared with sine wave, half-sine wave enhanced the degradation of stiffness. The increase of dynamic stress also intensified the softening of clay.

Key words: Zhuhai tunnel, saturated clay, cyclic loading, degradation index, shear modulus

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