Aiming at Nishihara model to describe the rheological characteristics of dual-pore-fracture media suggested by the author，a corresponding bolted body model was established，and the mathematical expressions were given for distributing uniformly the elastic modulus and shearing strength of bolt material into the bolted body. Simulating a hypothetical rectangular underground cavern，the 2D FEM analysis were carried out on the cases of cavern without bolting and with bolted body elements as well as with bar elements，respectively，and the displacements，stresses and plastic zones in the surrounding rock mass were analyzed and compared. The results show that the systematic bolting has certain restriction on the displacements of cavern boundary，but this effect is not proportional to the bolt length，and it is more obvious for the case with bolted body elements than for that with bar elements；there are obvious stress concentration phenomena in the bolted zones，and the distributions and values of stresses in the surrounding rock also have some changes with increase of the bolt length；the systematic bolting makes the plastic zones in the surrounding rock decrease obviously，but this effect also is not proportional to the bolt length；using bolted body elements and bar elements for the bolts with same length respectively，the areas of plastic zones obtained are close to each other，but the distribution shapes have some differences.