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Abstract Mechanical properties of soft rock materials in deep shaft are tested with experimental system of split Hopkinson pressure bar(SHPB). The experimental results indicate that the dynamic stress-strain curves of soft rock materials are of distinct plastic yield characteristics. Based on modified excess stress constitutive model，according to the function relationships of strain，strain rate and ，to simplify constitutive equation of modified excess stress model with dimensionless analysis，the simplified constitutive equation of modified excess stress model is obtained. And then，continuum damage theory and statistical damage theory are incorporated into the simplified constitutive equation of modified excess stress model account for the influence of damage on dynamic strength of rock，so the simplified constitutive equation of damage excess stress model is established. The simplified constitutive functions are fitted out respectively on the basis of experimental data. There is a good coherence between the stress-strain curves fitted by the simplified damage excess stress constitutive model and the experimental stress-strain curves.
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Received: 06 December 2011
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2013, Vol. 32 
