Journal Published Online: 07 December 2017
Volume 41, Issue 1

Creep Behavior and Long-Term Strength Characteristics of Greenschist Under Different Confining Pressures



Creep and long-term strength are important time-dependent behaviors of rock. To study the time-dependent behavior of hard rock under different confining pressures, conventional triaxial tests and multistage creep tests were conducted on the greenschist in the Jinping II Hydropower Station at different confining pressures. Based on the test results, the characteristics of axial, lateral, and volumetric creep were analyzed, and the creep properties under different confining pressures were also studied in detail and evaluated quantitatively by a simple model. Meanwhile, a new method is proposed by which the long-term strength can be determined using the inflection point in the isostrain-rate curve. The test results revealed that the creep was weakened and the ratio of long-term strength to instantaneous strength decreased with increasing confining pressure, during which the deformation of the rock sample transitioned from brittle to ductile. It was found that the duration of the transient creep stage decreased and the lateral strain was more sensitive to the creep stress than the axial strain when the confining pressure increased. It is also observed that the long-term strength determined by the inflection point method is consistent with those estimated by the creep rate in multistage creep tests, and the accuracy of the method proposed in this research is verified.

Author Information

Wang, Zhen
Department of Geotechnical Engineering, Tongji University, Shanghai, China
Shen, Mingrong
Department of Geotechnical Engineering, Tongji University, Shanghai, China Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education, Tongji University, Shanghai, China
Gu, Linlin
Department of Civil Engineering, Qingdao University of Technology, Qingdao, China
Zhang, Feng
Department of Civil Engineering, Nagoya Institute of Technology, Nagoya, Japan
Pages: 17
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Stock #: GTJ20170143
ISSN: 0149-6115
DOI: 10.1520/GTJ20170143