EXPERIMENTAL STUDY ON CONSTITUTIVE RELATION OF ROCK SPECIMENS IN BOHAI AREA AND ESTABLISHMENT OF A NEW CONSTITUTIVE MODEL OF ROCK DAMAGE

Bohai rock samples have been studied in order to speed up oil and gas resource exploitation in Bohai and improve the existing theory system of rock damage constitutive models. According to the test result parameters, a new damage constitutive model of rock is established. Firstly, with the test of variable temperature and confining pressure of rock specimens in the tri-axis test instrument, the whole stress-strain curves of rock samples are obtained. The Poisson's ratio, elastic modulus and maximum differential stress of the rock are calculated. Secondly, using the graphic method for Mohr stress circle, the cohesive force and internal friction angle of rock samples are determined. Lastly, according to parts of the test data, a new damage constitutive model of rock has been built. The model refers fewer parameters and simple calculation. The calculation results of the model and the whole stress-strain curves of test have verified the accuracy of this rock damage constitutive model. The conclusions of the study can provide experimental and theoretical support to improve the rock damage model and the efficient exploitation of petroleum resources on site.