EXPERIMENTAL RESEARCH ON LOAD/UNLOAD RESPONSE RATIO CONSIDERING HYSTERESIS EFFECT OF ROCK
DENG Huafeng1,2,HU Yayun1,2,LI Jianlin1,2,XIAO Zhiyong1,2,ZHOU Meiling1,2,HU Yu1,2
(1. Collaborative Innovation Center for Geo-Hazards and Eco-Environment in Three Gorges Area,China Three Gorges University,Yichang,Hubei 443002,China;2. Key Laboratory of Geological Hazards on Three Gorges Reservoir Area,Ministry of Education,China Three Gorges University,Yichang,Hubei 443002,China)
Abstract:Cyclic loading and unloading tests with constant amplitude were designed to analyze the change rules and the correlativity between load/unload response ratio and damage variable,and the change rules of stress-strain hysteresis time,load/unload response ratio,damage variable,the corresponding peak strain of peak stress were analyzed in detail. The results show that:(1) the stress-strain hysteresis time is not a constant during the test,which is obvious larger at the initial stage of the cycle loading and unloading and the stage of approaching destruction. (2) When the rock samples are approaching destruction,the stress-strain hysteresis time,load/unload response ratio,damage variable and the corresponding peak strain of peak stress all have obvious catastrophe,which shows good correlation among the mechanical parameters,and they are closely related to stress state and damage degree of the rock. (3) Considering the effect of rock damage on degree of medium uniformity of rock in cyclic loading and unloading test,correlative equation between load/unload response ratio and damage variable is modified,the result shows that with which can make damage degree of rock clearly described by load/unload response ratio. Research results have good reference value for analyzing the relationship between load/unload response ratio and damage variable,meanwhile,the relevant test methods can provide reference for similar tests.
RAY S K,SARKAR M,SINGH T N. Effect of cyclic loading and strain rate on the mechanical behavior of sandstone[J]. International Journal of Rock Mechanics and Mining Sciences,1999,36(4):543-549.
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