关键词: 白云岩, 孔隙度, 屈服模型, 岩石强度

Abstract:

Mechanical characteristics of porous dolostone was conducted systematically in order to investigate porosity effects on mechanical properties of dolostone samples, which were sampled from surface and more than 5000 m deep in Southeast Sichuan Province. The porosity is one of the critical physical properties of dolostone, which is often categorized into storage strata of petroleum or natural gas. The porosity ranges from 6% to 12% for these samples of dolostone. The experiments in the laboratory were performed with regard to uniaxial compressive test (UCT), Brazilian Split test (tension strength), direct shear test, as well as triaxial compressive test (TCT). The results of uniaxial compressive tests indicate that the uniaxial compressive strength decreases with increase of the porosity in dolostone; meanwhile similar results were achieved in the multiaxial tests, namely, the strength reduces as increase of porosity at the fixed confining pressure; whereas the peak strength of the triaxial compressive stress increases with the increase of confining pressure when the porosity is fixed. Finally, the yield function of MSPDu (Mises-Schleicher-Drucker-Prager Universal) model was introduced, which was employed to porous dolostone; the results of porous dolostone show that MSDPu model can describe well yield properties of the porous dolostone.

Key words: dolostone, porosity, yield model, strength of rock