An Experimental Study On Hydraulic Behavior In A Single Joint With Different JRC

Hydraulic behavior in fractured rock has an important effect on geotechnical engineering, such as water-grushing in excavation of underground chambers and tunnels, construction of dam foundation, exploitation of oiland terrestrial heat, burial of chemical material and nuclear waste, design on mine and so on. At present, cubic law based on parallel plate model has been accepted in geotechnical engineering field, and many scholars have done much research work to modify cubic law in aperture and roughness. For the aperture and roughness were acquired difficultly, the application of modified cubic law was limited. So the author proposed to represent hydraulic behavior in fractured rock with JRC (Joint Roughness Coefficient), and researched the influence of JRC on the coupling of fluid flow and stress with experiment.Based on the parallel plate model, analogized the former scholars' experiments, this experiment used RCCP of petroleum system to test the penetrability of joints with different JRC under different stress conditions. The making of the sample was first based on the typical roughness profiles by Barton, machininged the JRC templates using the numerical control wire cut EDM, then poured the sample with cement and drilled ten columniform concrete cores with different JRC. The experiment approached to practical engineering project much better with simulating different roughness joints. The measured parameters were acquired more easily and the productions had a better practicability and popularizability.Analyzed the results, two main conclusions were educed: (1) The permeability of a single joint decreased with the increasing effective stress, following the law of negative exponent, and JRC had small effect on this law. (2) The permeability of a single joint had a trend of decreased with the increasing of JRC under same effective stress conditions at middle-low effective stress level. But the regularity was not evident enough, and the fluctuation was extensively, which showed JRC had not been very great effect on penetrability.(3) Fractured rock came to a whole rock as the effective stress increased, and the influence of JRC on permeability had decreased.