结构面的存在改变了岩体力学性质，影响了岩体强度特征。基于统计岩体力学强度判据，结合摩尔-库仑准则，得到了含单组结构面岩体破坏的4种不同方式和相应的结构面倾角范围，推导了岩体强度由结构面控制转化为应力控制的临界围压表达式。在此基础上，根据岩石和结构面参数之间的关系，将含单组结构面岩体分为4类，并探讨了可能破坏方式和发生破坏的条件。最后，举例分析了含单组结构面闪长岩的强度特征，结果表明，该岩体属于第I类岩体，在垂向受压时先沿结构面后沿岩块破坏，临界围压为9.12 MPa；从全空间分析，该岩体强度各向异性显著，围压增大可使岩体在一些方向上受力时强度由结构控制转化为应力控制。

The existing of joints has great effect on the mechanical properties and strength characteristics of rock mass. In this study, four different failure modes of rock mass with one group of joints and the corresponding ranges of joint dip angles are obtained according to the strength criterion of statistical mechanics of rock mass and the Mohr-Coulomb failure criterion. An expression of the critical confining pressure is deduced for representing the transformation of rock mass strength from structure control to stress control. Moreover, rock masses with a group of joints are divided into four classes by the relationship between rock and joint parameters. Then the potential failure modes and the corresponding failure conditions are discussed. Finally, the strength characteristics of diorite with a group of joints are analyzed. The results show that the diorite belongs to class I rock mass. The diorite fails firstly along with the direction of joints and then fractures in the rock blocks at a critical confining pressure of 9.12 MPa under the axial pressure condition. It is found that the diorite has significant anisotropy from the spatial analysis, and the increase of confining pressure would result in the transfer of rock mass strength from structure control to stress control under the particular loading directions.