Improved elastic nonlinear normal deformation constitutive model of rock fractures
Some rock fracture elastic nonlinear normal deformation constitutive models were reviewed and the significant deviation of these models from experimental results at intermediate stress was pointed out. A new concept named half-closure stress σ1/2 was introduced to lay emphasis on analysis of the mathematic defects of both BB model and classical exponential model. The generalized exponential model proposed in Malama and Kulatilake (2003) was treated as an example for further statement of the necessary for model improving, meanwhile analyzing the deficiency of physical meaning of the initial normal stiffness of fracture Kni because of modification by accession of power function n on σn/ σ1/2. Based on the above research, the governing differential stress-displacement equation of fracture was established under monotonically increasing normal compressive loading and the concept of pseudo fracture maximum allowable closure Dma= ξdma was defined. Then a new 3-parameter constitutive model which improved fracture elastic nonlinear normal deformation behavior was proposed. It was proved strictly that BB model and classical exponential model were two special cases of the new model. The new parameter was easy to determine, and the mathematic defects of BB model and classical exponential model were overcome. Counteracting the deviation of simulated results of these traditional nonlinear models with test results at intermediate stress, the physical meaning of Kni did not lose with the accession of the new parameter ξ. The predication results fitted the test results well in adopting the new model for the predication of others test data, which verified the feasibility of the new model.
rock fracture elastic nonlinearity normal deformation constitutive model halfclosure stress
J.Yu C.M.Lin Y.Chen
School of Civil Engineering, Huaqiao University, Xiamen 361021, China
国际会议
香港
英文
1-5
2009-05-19（万方平台首次上网日期，不代表论文的发表时间）