裂隙的大量存在使岩体的变形特性变得非常复杂，而在采用数值分析方法时，常常忽略微裂隙对岩体力学特性的影响。为了明确微裂隙对岩体变形参数的影响，通过变形等效原理，对含单一微裂隙的岩体的变形参数进行估算。计算结果表明：岩体的变形特性与微裂隙倾角、长度和荷载方向有关；微裂隙越长，岩体的变形模量越小，泊松比越大；微裂隙倾角与荷载方向的夹角越小，岩体的各向异性越明显，但是，随着夹角的增大，岩体不同方向上的变形模量逐渐减小，泊松比逐渐增大，岩体的各向异性逐渐减弱，当微裂隙与荷载方向的夹角为45°时，岩体则表现为各向同性。

A large number of cracks have made the deformation properties of rock mass become very complex. However, the effect of these microcracks is often neglected in the research of rock mass deformation properties using numerical simulation method. In order to make clear the effect of theses microcracks on the deformation parameters of rock mass, the deformation parameters of  rock mass that contains one single microcrack are estimated based on equivalent deformation principle. Results show that the deformation characteristics of rock mass are related with the dip angle, the length and also the load orientation of the microcrack. When the length of the microcrack is longer, the deformation module of the rock mass is smaller and the Poisson ratio is bigger. When the intersection angle between the microcrack dip angle and the load orientation is smaller, the anisotropy of rock mass is more evident. Whereas with the increase of this intersection angle, the deformation moduli in different orientations are decreased, the Poisson ratios are increased and the anisotropy of the rock mass is weakened. When the intersection angle between the microcrack dip angle and the load orientation is 45°, the rock mass will be isotropic. 