JRMGE / Vol 14 / Issue 1
A new estimation method and an anisotropy index for the deformation modulus of jointed rock masses
Bohu Zhang, Junyan Mu, Jun Zheng, Qing Lv, Jianhui Deng
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a State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu, 610500, China
b School of Geoscience and Technology, Southwest Petroleum University, Chengdu, 610500, China
c Department of Civil Engineering, Zhejiang University, Hangzhou, 310058, China
d Center for Balance Architecture, Zhejiang University, Hangzhou, 310007, China
e State Key Laboratory of Hydraulics and Mountain River Engineering, College of Water Resource and Hydropower, Sichuan University, Chengdu, 610065, China
2022, 14(1): 153-168. doi:10.1016/j.jrmge.2021.06.005
Received: 2021-01-15 / Revised: 2021-04-09 / Accepted: 2021-06-10 / Available online: 2021-07-22
2022, 14(1): 153-168.
doi:10.1016/j.jrmge.2021.06.005
Received: 2021-01-15
Revised: 2021-04-09
Accepted: 2021-06-10
Available online: 2021-07-22
The deformation modulus of a rock mass is an important parameter to describe its mechanical behavior. In this study, an analytical method is developed to determine the deformation modulus of jointed rock masses, which considers the mechanical properties of intact rocks and joints based on the superposition principle. Due to incorporating the variations in the orientations and sizes of joint sets, the proposed method is applicable to the rock mass with persistent and parallel joints as well as that with non-persistent and nonparallel joints. In addition, an anisotropy index AIdm for the deformation modulus is defined to quantitatively describe the anisotropy of rock masses. The range of AIdm is from 0 to 1, and the more anisotropic the rock mass is, the larger the value of AIdm will be. To evaluate the proposed method, 20 groups of numerical experiments are conducted with the universal distinct element code (UDEC). For each experimental group, the deformation modulus in 24 directions are obtained by UDEC (numerical value) and the proposed method (predicted value), and then the mean error rates are calculated. Note that the mean error rate is the mean value of the error rates of the deformation modulus in 24 directions, where for each direction, the error rate is equal to the ratio of numerical value minus predicted value to the numerical value. The results show that (i) for different experimental groups, the mean error rates vary between 5.06% and 22.03%; (ii) the error rates for the discrete fracture networks (DFNs) with two sets of joints are at the same level as those with one set of joints; and (iii) therefore, the proposed method for estimating the deformation modulus of jointed rock masses is valid.
Keywords: Deformation modulus, Analytical method, Anisotropy index, Jointed rock masses, Mechanical behavior, Discrete fracture network (DFN)
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Author(s) Information
Jun Zheng
Jun Zheng is an Associate Professor and a doctoral supervisor in College of Civil Engineering and Architecture at Zhejiang University, China. He obtained his Joint PhD in geotechnical engineering from Sichuan University (China) and the University of Arizona (USA) in 2014. He was a Visiting Scholar at Delft University of Technology in 2016. His research interests are in rock mechanics and geohazard prevention and mitigation, particularly including (1) geometric model and computer simulation of rock mass structures; (2) relationship between geometric model and mechanical behaviors of rock masses; (3) application of artificial intelligence in rapid acquisition of geometric parameters of rock discontinuities; and (4) probabilistic stability analysis of rock masses. He is responsible for two projects sponsored by the National Natural Science Foundation of China, and has published over 60 scientific papers. Dr. Zheng has won several awards including Excellent Doctoral Dissertation Award of Chinese Society for Rock Mechanics and Engineering (CSRME) in 2016 and Natural Science Award of CSRME in 2018. He was selected in Young Elite Scientists Sponsorship Program by China Association for Science and Technology (CAST) in 2018. He is serving as a young editorial board member of an international journal and a specially invited editorial board member of a domestic journal, and has served as a reviewer for about 28 rock mechanics/geotechnical/engineering geology journals.