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Abstract Virtual joint is adopted in the discontinuous deformation analysis(DDA)，which can provide path for block failure and fracture development. Therefore，the failure process of jointed rock mass is a progress of initiation，extending and connecting of joints inside rock mass；and attenuation of virtual joint mechanical parameters represents the strength attenuation in the process of rock failure. The attenuation law of virtual joint mechanical parameters is studied by introducing the definition of virtual joint connectivity rate；and the attenuation formula of virtual joint mechanical parameters is established. According to the phenomenon of mechanical parameters attenuation in rock failure，the strength criterion(Jennings criterion and the maximum tensile strength criterion) for intermittent jointed rock masses are studied. Programming the attenuation law of virtual joint mechanical parameters and improved strength formula of intermittent joint into DDA to simulate the fracturing process of intermittent joint. At last，the method is validated by comparing the computation results with shear test results.
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Received: 03 February 2010
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2010, Vol. 29 
