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Effect of Joint Orientation Distribution on Hydraulic Behavior of the 2-D DFN System

절리의 방향분포가 이차원 DFN 시스템의 수리적 특성에 미치는 영향

  • Han, Jisu (Department of Energy Resources Engineering, Pukyong National University) ;
  • Um, Jeong-Gi (Department of Energy Resources Engineering, Pukyong National University)
  • 한지수 (부경대학교 에너지자원공학과) ;
  • 엄정기 (부경대학교 에너지자원공학과)
  • Received : 2016.01.13
  • Accepted : 2016.02.21
  • Published : 2016.02.28

Abstract

A program code was developed to calculate block hydraulic conductivity of the 2-D DFN(discrete fracture network) system based on equivalent pipe network, and implemented to examine the effect of joint orientation distribution on the hydraulic characteristics of fractured rock masses through numerical experiments. A rock block of size $32m{\times}32m$ was used to generate the DFN systems using two joint sets with fixed input parameters of joint frequency and gamma distributed joint size, and various normal distributed joint trend. DFN blocks of size $20m{\times}20m$ were selected from center of the $32m{\times}32m$ blocks to avoid boundary effect. Twelve fluid flow directions were chosen every $30^{\circ}$ starting at $0^{\circ}$. The directional block conductivity including the theoretical block conductivity, principal conductivity tensor and average block conductivity were estimated for generated 180 2-D DFN blocks. The effect of joint orientation distribution on block hydraulic conductivity and chance for the equivalent continuum behavior of the 2-D DFN system were found to increase with the decrease of mean intersection angle of the two joint sets. The effect of variability of joint orientation on block hydraulic conductivity could not be ignored for the DFN having low intersection angle between two joint sets.

Keywords

fractured rock mass;joint orientation distribution;discrete fracture network;block hydraulic conductivity;numerical analysis

Acknowledgement

Supported by : 한국연구재단

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