Study On The Rheological Constitutive Model Of Rock And Its Intelligent Identification

Rock theology is one of the most important reasons why the adjoining rock in the geotechnical engineering is often apt to lose its stability and be damaged. Based on a general review on the previous correlative researches, the thesis set the research subject of the rheological constitutive model of rock and performed a creative research on building and identifying the constitutive model.In order to make the scheduled research work be done successfully, at first it mend two old CFQ-1 uniaxial creep testing instruments in its laboratory, one of which was refitted so that the uniaxial creep test of rock and the direct shearing creep test of rock structural face could all be performed in the lab .In addition, its also designed a new creep-relaxation coupling testing instrument for the research on soft rock rheology.For the sake of getting over the trouble of the manufacture of soft rock specimens, it developed a kind of equivalent material whose original components are paraffine, marble sand and vaseline etc .The material is suitable for the experimental research on soft rock rheology because it is similar in mechanical characters to soft and weak rock such as mudshale and mudstone.It carried out the multi-stage incremental cycling loading and unloading creep test of the equivalent material specimens of soft rock which contain or not the structural face whose obliquity is 0 ,15 ,30 ,45 and put forward a new multiple rheological mode which is fit for the description of the complicated rheological mechanical characters of soft rock .On the basis of the new model, the structural effects in the course of the creep of soft rock was in detail probed into and a nonlinear regressive function was gained about the parameters of the multiple model and the obliquity of the structural face.On the basis of previous tests in its lab, it studied the scale effect of rock creep .By analyzing the results of the uniaxial creep test on the sandshale specimens of different size, whose constitutive model is SALUSTOWICZ model, it studied the size effect of the model parameters and gained the quantitative relation between the value of the constitutive parameters of the rheological model and the size of rock specimens. And then it further probed into the concept of the dimension of the continuous micro-element associated with the hypothesis of the continuous medium of rock mass in the geotechnical engineering and its applying scopeBy performing the multi-stage incremental cycling loading and unloading compressing shearing creep test, it discussed in detail the creep behaviors and put forward a new multiple mechanical model suitable for the description of the rheology of the structural face. Then it further studied the surface roughness effect of the structural face and also gained a nonlinear regressive function on the model parameters and the surface roughness.By using the new creep-relaxation coupling testing instrument to perform a test on soft rock, it discussed the simple and effective working principle of the instrument and drew the conclusions that the long-term strength and the rheological constitutive model parameters of soft rock could be determined by the test using the new instrument which have the "single-stage" loading and "multi-stage" loading method and it is more subjective to determine the long-term strength of soft rock by the "multi-stage" loading method than the "single-stage" loading method .The coupling testing instrument is easy to use ,effective .stable and of high precision .Its testing results was safe so that they could be used in engineering practice .From the viewpoint of the mesco structure of the rock material, first it analyzed the high complexity of the inner stress state in the process of creep and failure of rock material, which is reflected from the "softing effect" and "hardening effect"; Then using the renormalization groupmethod to study the creep and failure process it found that there is a self-organized criticality which is characterized by the critical cracking probability of the micro...