The Study On Opening Displacement Of Brittle Rockmass In High Geostress

The study on the stability of large underground caverns has always been the hot topics of many rock mechanics professors'attention. Based on the happenning mechanism of openning displacement,this paper makes a study of topical stress-strain relationship of brittle rockmass in high geo-stress zone.At the same time,considering the theory of dissipation of energy,this paper makes a preliminary study on the constitutive equation of brittle rockmass in high geostress zone and their engineering application.First,According to the special high geostress of large underground caverns and the deformation features of brittle rockmass,the elastic-brittle constitutive equation is deduced from stress-strain relationship.A simple sample is calculated in order to validate it.Besides this one,a variational-modulus model has been received during the unload course from the point of dissipation of energy and this aspect is considered in the constitutive equation.At last, dissipation of energy can be gained from the theory of crack growth.Second, taking advantage of FLAC3D,wecompile the above constitutive equation model on the Microsoft Visual C++environment,and realize the secondary further development of FLAC3D.The operation process of this program is also described detailedly.Third,the stability of surrounding rock and the excavation step in the large underground caverns of Jinping hydropower station is simulated by using this developed program.The elastic and plastic result are also calculated to make a contrast between different constitutive models.According to the comparative results,the model is basically reasonable.Finally,some rational suggestions are put forward for the long-term deformation and stability of large underground caverns.