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Abstract The stress-strain curves of rocks are composed of two parts，which are pre-peak region and post-peak region. In the pre-peak region of stress-strain curve，rocks are usually regarded as elastomer. At this stage，the constitutive relationship is linearly elastic. However，in the post-peak region，the curve could not be determined by classical theory because the fracture morphology and the stress drop of the rocks are hard to describe. Thus，the post-peak modulus is the key of the mechanical behavior research. Based on Mohr-Coulomb criterion，the paper uses internal friction angle as intermediate variable to propose post-peak elastic modulus. The nonlinear post-peak stress-strain relationship of rock is established. In numerical cases，the stress-strain curves under different confining pressures are obtained and they agree well with the test data. It is concluded that the fitting curve model proposed by this paper is reasonable and the model could describe the post-peak mechanical behavior of marbles under various confining pressures preferably.
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Received: 10 February 2011
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2011, Vol. 30 
