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.

State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Southwest Petroleum University,Chengdu,610500,China;School of Geoscience and Technology,Southwest Petroleum University,Chengdu,610500,China;Department of Civil Engineering,Zhejiang University,Hangzhou,310058,China;Center for Balance Architecture,Zhejiang University,Hangzhou,310007,China;State Key Laboratory of Hydraulics and Mountain River Engineering,College of Water Resource and Hydropower,Sichuan University,Chengdu,610065,China

[1]Bohu Zhang;Junyan Mu;Jun Zheng;Qing Lv;Jianhui Deng-.A new estimation method and an anisotropy index for the deformation modulus of jointed rock masses)[J].岩石力学与岩土工程学报（英文版）,2022(01):153-168

nonparallel,AIdm,DFNs

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