Normal creep deformation law of rock fracture and the influence of seepage

doi:10.3969/j.issn.1673-9787.2012.04.010

Abstract：The normal creep deformation of rock fracture is one of the important rock mechanical properties. The paper discusses the normal creep characteristics of rock fracture and the influence of seepage to it by ana- lyzing the normal creep mechanism of rock fracture and by conducting normal creep tests for dry rock fracture and the rock fracture under seepage conditions respectively. The results show that the instantaneous effective stress is always equal to the compression strength of asperity of rough rock fracture, thus the initial normal creep deformation is obvious, and then creep rate reduce gradually with increment of contact area; normal creep deformation will become more obvious while water is flowing through the rock fracture. Moreover, that the normal creep amount of rock fracture under first loading stress is larger than those of following loading stresses. However, the increase of normal creep deformation of rock fracture can not determine its reduction of seepage capacity, and the seepage capacity of rock fracture can even increase with its normal creep closure when there is enough hydraulic flushing ability. The creep closure of rock fracture has a close relation with roughness of rock fracture surface, and the greater the roughness is, the greater the creep amount is. The results have a certain reference value for numerical simulation and engineering practice related to the normal creep deformation of rock fracture.