TY - JOUR
T1 - Modeling spatial fracture intensity as a control on flow in fractured rock
AU - Lee, Chen Chang
AU - Lee, Cheng Haw
AU - Yeh, Hsin Fu
AU - Lin, Hung I.
N1 - Funding Information:
Acknowledgments The authors would like to thank C.Z. Tong, F.L. Chang, David C.F. Shih, and W.S Chuang at the Institute of Nuclear Energy Research in Taiwan for their help in generating the fracture networks and flow simulation. Part of financial support came from National Research Council and Institute of Nuclear Energy Research in Taiwan.
PY - 2011/7
Y1 - 2011/7
N2 - Spatial fracture intensity (P32, fracture area by volume) is an important characteristic of a jointed rock mass. Although it can hardly ever be measured, P32 can be modeled based on available geological information such as spatial data of the fracture network. Flow in a mass composed of low-permeability hard rock is controlled by joints and fractures. In this article, models were developed from a geological data set of fractured andesite in LanYu Island (Taiwan) where a site is investigated for possible disposal of low-level and intermediate-level radionuclide waste. Three different types of conceptual models of spatial fracture intensity distribution were generated, an Enhanced Baecher's model (EBM), a Levy-Lee Fractal model (LLFM) and a Nearest Neighborhood model (NNM). Modeling was conducted on a 10 × 10 × 10 m synthetic fractured block. Simulated flow was forced by a 1% hydraulic gradient between two vertical x-z faces of the cube (from North to South) with other boundaries set to no-flow conditions. Resulting flow vectors are very sensitive to spatial fracture intensity (P32). Flow velocity increases with higher fracture intensity (P32). R-squared values of regression analysis for the variables velocity (V/Vmax) and fracture intensity (P32) are 0.293, 0.353, and 0.408 in linear fit and 0.028, 0.08, and 0.084 in power fit. Higher R2 values are positively linked with structural features but the relation between velocity and fracture intensity is non-linear. Possible flow channels are identified by stream-traces in the Levy-LeeFractal model.
AB - Spatial fracture intensity (P32, fracture area by volume) is an important characteristic of a jointed rock mass. Although it can hardly ever be measured, P32 can be modeled based on available geological information such as spatial data of the fracture network. Flow in a mass composed of low-permeability hard rock is controlled by joints and fractures. In this article, models were developed from a geological data set of fractured andesite in LanYu Island (Taiwan) where a site is investigated for possible disposal of low-level and intermediate-level radionuclide waste. Three different types of conceptual models of spatial fracture intensity distribution were generated, an Enhanced Baecher's model (EBM), a Levy-Lee Fractal model (LLFM) and a Nearest Neighborhood model (NNM). Modeling was conducted on a 10 × 10 × 10 m synthetic fractured block. Simulated flow was forced by a 1% hydraulic gradient between two vertical x-z faces of the cube (from North to South) with other boundaries set to no-flow conditions. Resulting flow vectors are very sensitive to spatial fracture intensity (P32). Flow velocity increases with higher fracture intensity (P32). R-squared values of regression analysis for the variables velocity (V/Vmax) and fracture intensity (P32) are 0.293, 0.353, and 0.408 in linear fit and 0.028, 0.08, and 0.084 in power fit. Higher R2 values are positively linked with structural features but the relation between velocity and fracture intensity is non-linear. Possible flow channels are identified by stream-traces in the Levy-LeeFractal model.
UR - http://www.scopus.com/inward/record.url?scp=79959599395&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79959599395&partnerID=8YFLogxK
U2 - 10.1007/s12665-010-0794-x
DO - 10.1007/s12665-010-0794-x
M3 - Article
AN - SCOPUS:79959599395
SN - 1866-6280
VL - 63
SP - 1199
EP - 1211
JO - Environmental Earth Sciences
JF - Environmental Earth Sciences
IS - 6
ER -