Journal of Shanghai Jiaotong University ›› 2016, Vol. 50 ›› Issue (01): 78-83.

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Mechanical Property Test at Different Unloading Velocities of Metamorphic Quartz Sandstone

GUO Xifeng1,2,YIN Jianmin1,YAN Echuan2,ZHANG Lijie1,2   

  1. (1. Key Laboratory of Geotechnical Mechanics and Engineering of the Ministry of Water Resources, Yangtze River Scientific Research Institute, Wuhan 430010, China;2. Faculty of Engineering, China University of Geosciences(Wuhan),Wuhan 430074, China)
  • Received:2014-12-05 Online:2016-01-29 Published:2016-01-29

Abstract: Abstract: To study rock mechanical characteristics at different unloading velocities, taking the metamorphic quartz sandstone from Dabenliugou quarry special high slope in Jinping Hydropower Station as an example, unloading tests at different unloading velocities and confining pressures were conducted. Based on the tests, relationship curves between stress and strain were obtained, and affection laws of unloading velocity on stress and strain relationship, failure properties, failure stress difference, strength parameters were mainly studied. The results show that the brittle feature of unloading effect on rock failure is more obvious. The specimens under conventional loading test are compression shear failure, while the unloading specimens are tension shear failure. Elastic modulus is decreased with confining. As Vu becomes faster, the nonlinearity become more obvious, while the Poisson ratio is increased slowly. The rock cohesion is reduced but the inner friction angle is increased under unloading condition.

Key words: unloading velocity, triaxial unloading test, deformation characteristics, strength parameters

CLC Number: