Study on the Effect of Length distribution function, Fisher constant and the Angle of Discontinuities on the Effective Connectivity of Discrete Fracture Network

The study results depict that the geometrical characteristics of the fractures have more effect on the uncertainty of seepage into underground spaces than the hydraulic characteristics of the fractures. The effect of the fracture geometry on the permeability of the network can be studied through connectivity. The effective connectivity between the discontinuities is an appropriate index for computing the hydraulic conductivity of the fracture network. To this end, 3DFAM5 code has been developed to identify the effect of the geometrical characteristics of the discontinuities on the effective connection of the fracture network. Then, the effect of the discontinuity length probability density function, Fisher constant and the angle between the discontinuities on the connectivity and the hydraulic conductivity of the network were assessed making use of the 3DFAM code. The modeling results indicate that the network has more connectivity in case of gamma distribution function rather than the exponential and lognormal distributions. Besides, according to the type of the probability density function, the effective connectivity value and hydraulic conductivity of the network increases when the Fisher constant is less than 100 - 150. In addition, the effective connectivity increases when the angle between the joint sets increase. Nevertheless, this trend and amount of variations rely upon the type of the probability density function.

کلیدواژه ها:

Discontinuity ، geometrical characteristics ، Discrete Fracture Network ، numerical method ، effective connectivity