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| STUDY OF REPRESENTATIVE ELEMENTARY VOLUME FOR FRACTURED ROCK MASS BASED ON THREE-DIMENSIONAL FRACTURE CONNECTIVITY |
| WANG Xiaoming，XIA Lu，ZHENG Yinhe，YU Qingchun |
| (School of Water Resources and Environment，China University of Geosciences，Beijing 100083，China) |
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Abstract Three-dimensional(3D) fracture connectivity，which can comprehensively reflect the fracture features，is a key parameter for evaluating the stability of engineering rock masses. For the purpose of determining a representative 3D connectivity value，the scale effect of 3D connectivity is investigated based on projection method and the representative elementary volume(REV) of the study rock mass is further estimated. First，fracture data collected from an exploration tunnel are statistically analyzed and used to generate a large discrete fracture network of 100 m×100 m×140 m by an inverse method. Inside the fracture network，reference planes with different sizes ranging from 5 m×5 m to 100 m×100 m are sampled 10 times on different elevations. A projection method is adopted to calculate horizontal 3D fracture connectivity of each reference plane and the relationship between the 3D fracture connectivity value and the study domain size is analyzed. The REV of the rock mass is estimated based on a series of T-tests and F-tests. The T-tests and F-tests are performed to determine whether the mean value and variance of fracture connectivity for different sizes are statistically equal to the largest size，respectively. The results show that a size of 65 m×65 m could be viewed as the REV，beyond which the mean value and variance of the connectivity converge to a stable state.
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Received: 21 September 2012
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2013, Vol. 32 
