(1. Institute of Geotechnical Engineering，Hohai University，Nanjing，Jiangsu 210098，China；2. Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering，Hohai University，Nanjing，Jiangsu 210098，China；3. Nanjing Engineering Investigation Institute of Nuclear Industry，Nanjing，Jiangsu 210003，China)
Abstract：The uniaxial compression-deformation test，cyclic loading and unloading tests on slightly weathered and middle differentiation biotite granite comes from the Changjiang of Hainan nuclear power first-stage construction conventional island are performed on the RMT–150B multi-function automatic rigid rock servo controlled testing machine. The granite hysteretic characteristics of dynamic stress-dynamic strain curves and the law between elastic modulus and dynamic elastic modulus，damping ratio are researched. And the viscoelastic generalized Kelvin rheological model is used to describe granite hysteresis curve and energy loss. The results show that the curves of strain and stress for loading and unloading are hysteresis loops. With the increase of cyclic number，hysteresis loops move to the direction of axial strain increasing，more and more dense. The areas of hysteresis loop and the maximum elastic strain energy decrease with increase of elastic modulus；however the dynamic elastic modulus is opposite. First，damping ratio increases with increase of elastic modulus；but after reaching its peak value，damping ratio decreases with increase of elastic modulus. The biotite granite hysteretic loop and energy loss can describe well by generalized Kelvin rheological model. The results offer great reference to seismic response analysis and site safety evaluation of the Changjiang nuclear power plant.
