TY - JOUR
T1 - Stochastic fracture geometry modeling in 3-D including validations for a part of Arrowhead East Tunnel, California, USA
AU - Kulatilake, Pinnaduwa H.S.W.
AU - Um, Jeong Gi
AU - Wang, Mingyu
AU - Escandon, Richard F.
AU - Narvaiz, John
N1 - Funding Information:
Authors are grateful to Metropolitan Water District of Southern California for providing financial support for this research.
PY - 2003/10
Y1 - 2003/10
N2 - Eight-hundred and fifty nine fractures of a gneissic rock mass were mapped using 16 scanlines placed on steep rock exposures that were within 300 m of a tunnel alignment before the tunnel excavation. These data were analyzed using the software package FRACNTWK to find the number of fracture sets that exist in the rock mass, 3-D fracture frequency for each set and the probability distributions of orientation, trace length, fracture size in three dimensions (3-D) and spacing for each of the fracture sets. In obtaining these distributions corrections were applied for sampling biases associated with orientation, trace length, size and spacing. Developed stochastic 3-D fracture network for the rock mass was validated by comparing statistical properties of observed fracture traces on the scanlines with the predicted fracture traces on similar scanlines. The one-dimensional (1-D) fracture frequency of the rock mass in all directions in 3-D was calculated and is presented in terms of a stereographic plot. The 1-D fracture frequency along the tunnel alignment direction was predicted to be about 6.5 fractures/m before the tunnel excavation. This prediction was found to be in excellent agreement with the observed values obtained about 1 year later during the tunnel excavation. This was another validation conducted for the developed 3-D fracture network.
AB - Eight-hundred and fifty nine fractures of a gneissic rock mass were mapped using 16 scanlines placed on steep rock exposures that were within 300 m of a tunnel alignment before the tunnel excavation. These data were analyzed using the software package FRACNTWK to find the number of fracture sets that exist in the rock mass, 3-D fracture frequency for each set and the probability distributions of orientation, trace length, fracture size in three dimensions (3-D) and spacing for each of the fracture sets. In obtaining these distributions corrections were applied for sampling biases associated with orientation, trace length, size and spacing. Developed stochastic 3-D fracture network for the rock mass was validated by comparing statistical properties of observed fracture traces on the scanlines with the predicted fracture traces on similar scanlines. The one-dimensional (1-D) fracture frequency of the rock mass in all directions in 3-D was calculated and is presented in terms of a stereographic plot. The 1-D fracture frequency along the tunnel alignment direction was predicted to be about 6.5 fractures/m before the tunnel excavation. This prediction was found to be in excellent agreement with the observed values obtained about 1 year later during the tunnel excavation. This was another validation conducted for the developed 3-D fracture network.
KW - Case study
KW - Fracture geometry
KW - Fracture network validation
KW - Probability distributions
KW - Statistical modeling
KW - Tunnel site
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U2 - 10.1016/S0013-7952(03)00087-5
DO - 10.1016/S0013-7952(03)00087-5
M3 - Article
AN - SCOPUS:0041845412
SN - 0013-7952
VL - 70
SP - 131
EP - 155
JO - Engineering Geology
JF - Engineering Geology
IS - 1-2
ER -