Use of an Integrated Discrete Fracture Network Code for Stochastic Stability Analyses of Fractured Rock Masses

2011 ◽  
Vol 45 (2) ◽  
pp. 159-181 ◽  
Author(s):  
V. Merrien-Soukatchoff ◽  
T. Korini ◽  
A. Thoraval
Keyword(s):  
Stochastic Stability ◽  
Fractured Rock ◽  
Fracture Network ◽  
Network Code ◽  
Discrete Fracture Network ◽  
Rock Masses ◽  
Stability Analyses ◽  
Discrete Fracture ◽  
Fractured Rock Masses

scholarly journals Study on Water Inflow Variation Law of No.1 Shaft Auxiliary Shaft in HighLiGongshan Based on Dual Medium Model

Symmetry ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 930
Author(s):  
Jiabin Li ◽  
Yonghong Wang ◽  
Zhongsheng Tan ◽  
Wen Du ◽  
Zhenyu Liu
Keyword(s):  
Rock Mass ◽  
Continuous Medium ◽  
Fractured Rock ◽  
Analytical Formula ◽  
Fracture Network ◽  
Discrete Fracture Network ◽  
Water Inflow ◽  
Fracture Group ◽  
Medium Model ◽  
Discrete Fracture

When the fracture is not developed and the connectivity is poor, the original single medium simulation cannot meet the accuracy requirements. Now, the seepage simulation of fractured rock mass has gradually developed from equivalent continuous medium to dual medium and multiple medium. However, it is still difficult to establish the connection between a discrete fracture network model and a continuous medium model, which makes it difficult to simulate the influence of fracture location on the seepage field of rock mass. As the excavation direction of the shaft is vertically downward, the surrounding strata are symmetrical around the plane of the shaft axis, which is different from the horizontal tunnel. Taking the auxiliary shaft of the No.1 Shaft in HighLiGongshan as the engineering background, combined with Monte Carlo methods and DFN generator built in FLAC3D5.01, a discrete fracture network is generated. Based on the dual medium theory, MIDAS is used to optimize the modeling of each fracture group. At the same time, the concept of “Fracture Weakening area” is introduced, and the simulation is carried out based on a fluid–solid coupling method. It is found that the simulation effect is close to the reality. The water inflow increases with the increase of shaft excavation depth, and the water inflow at the end of excavation is nearly three times larger than the initial value. Combined with Legendre equation, a new analytical formula of water inflow prediction is proposed. It is found that this analytical formula is more sensitive to permeability and has a greater safety reserve.

scholarly journals Correlations between Geometric Properties and Permeability of 2D Fracture Networks

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
Xiaolin Wang ◽  
Liyuan Yu ◽  
Hanqing Yang
Keyword(s):  
Fractured Rock ◽  
Rock Fracture ◽  
Fractal Dimensions ◽  
Fracture Network ◽  
Network Structures ◽  
Rock Masses ◽  
Fracture Networks ◽  
Geometric Properties ◽  
Equivalent Permeability ◽  
Fractured Rock Masses

The equivalent permeability of fractured rock masses plays an important role in understanding the fluid flow and solute transport properties in underground engineering, yet the effective predictive models have not been proposed. This study established mathematical expressions to link permeability of 2D fracture networks to the geometric properties of fractured rock masses, including number density of fracture lines, total length of fractures per square meter, and fractal dimensions of fracture network structures and intersections. The results show that the equivalent permeability has power law relationships with the geometric properties of fracture networks. The fractal dimensions that can be easily obtained from an engineering site can be used to predict the permeability of a rock fracture network. When the fractal dimensions of fracture network structures and intersections exceed the critical values, the effect of randomness of fracture locations is negligible. The equivalent permeability of a fracture network increases with the increment of fracture density and/or fractal dimensions proportionally.

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