scholarly journals Embedded Discrete Fracture Networks to Analyze Groundwater Inflows during Tunnel Drilling

2021 ◽  
Vol 42 (1) ◽  
pp. e89889
Author(s):  
Adriana Piña ◽  
Diego Cortes ◽  
Leonardo David Donado ◽  
Daniela Blessent
Keyword(s):  
Fracture Density ◽  
Fracture Networks ◽  
Statistical Parameters ◽  
Fracture Length ◽  
Estimated Parameters ◽  
Discrete Fracture Networks ◽  
Discrete Fracture ◽  
Order Of Magnitude ◽  
Simulated Groundwater ◽  
Aperture Distribution

Tunnels commonly go through fracture zones that used to be analyzed as an equivalent porous medium with homogeneous permeability. However, it is a rough simplification that overlooks the connection triggered by underground works in fractured massifs. This study introduces the use of synthetic discrete fracture networks (DFN) to analyze groundwater inflows through tunnel excavation in a fractured zone considering the daily advance of the drilling front. First, a hypothetical case with six different settings varying the fracture density, the fracture length, and the aperture distribution is analyzed. Each setting has about 100 iterations. DFN hydraulic properties were estimated and compared with previous DFN studies, displaying the same behavior even though the magnitude of the estimated parameters differs. As an application example, structural measurements of the Alaska fault zone in the La Linea massif (Colombia) are used to obtain the statistical parameters of the fracture length and aperture distributions to generate the DFN. Five settings varying the fracture density are built, obtaining measured and simulated groundwater inflows of the same order of magnitude. These results highlight the potential of the synthetic DFN to analyze tunnels’ effects on groundwater flow.

scholarly journals On the Density Variability of Poissonian Discrete Fracture Networks, with application to power-law fracture size distributions

2019 ◽  
Vol 49 ◽  
pp. 77-83 ◽  
Author(s):  
Etienne Lavoine ◽  
Philippe Davy ◽  
Caroline Darcel ◽  
Romain Le Goc
Keyword(s):  
Size Distribution ◽  
Power Law ◽  
Analytical Solutions ◽  
Three Dimensional ◽  
Size Distributions ◽  
Fracture Density ◽  
Fracture Networks ◽  
Discrete Fracture Networks ◽  
Discrete Fracture ◽  
Fracture Size

Abstract. This paper presents analytical solutions to estimate at any scale the fracture density variability associated to stochastic Discrete Fracture Networks. These analytical solutions are based upon the assumption that each fracture in the network is an independent event. Analytical solutions are developed for any kind of fracture density indicators. Those analytical solutions are verified by numerical computing of the fracture density variability in three-dimensional stochastic Discrete Fracture Network (DFN) models following various orientation and size distributions, including the heavy-tailed power-law fracture size distribution. We show that this variability is dependent on the fracture size distribution and the measurement scale, but not on the orientation distribution. We also show that for networks following power-law size distribution, the scaling of the three-dimensional fracture density variability clearly depends on the power-law exponent.

Sign in / Sign up

Export Citation Format

Share Document