Study On The Characteristics And Mechanics Mechanism Of The Deformation Of The Tunnel After The Rock Peak

The deformation and destruction of deep underground tunnel(tunnel and roadway)has always been an important research topic,The changes of the mechanical nature is even more elusive.After excavation,the stress state of the surrounding rock will be changed,and the original three-way stress state will become two-way stress state,the deformation features of surrounding rock are obvious and the deformation of surrounding rock can be transformed from brittle state to plastic state.The softening of the surrounding rock and the phenomenon of the expansion are prominent,and in the deep underground chamber,the high stress field and high ground stress field make the surrounding rock reach its peak strength states after excavation,and its destruction degree is large.In a sense,the deformation of surrounding rock is a complicated deformation process after the peak strength of the surrounding rock.Although at present there are many stories about the circumference after one rock deformation results for reference,but according to the deformation and failure mechanism of surrounding rock cavern excavation is still exist many suspects,such as the changes of the mechanical properties of surrounding rock after deformation of surrounding rock itself and the influence of the stress,deformation and stability of surrounding rock,etc.by the change of the surrounding rock mechanics properties.Based on the above mentioned and previous studies,this paper draws on others’ experimental results and summarizes them.Considering the deformation and failure characteristics of the underground chamber bees,the geological conditions and the complex characteristics of the rock mass are given in consideration of the deformation of the rock mass in the excavation,then proper zoning of underground chamber,the total stress strain curves obtained from the data of the conventional triaxial test in the laboratory are introduced to introduce the concept of softening modulus and the determination method..Surrounded by cavern were softening phase of the "five points" model after further discussion softening modulus,cohesion,internal friction Angle changes,and using Matlab of minimum error of fitting way to get the relationship of softening modulus,cohesion,internal friction Angle.Furthermore,the characteristics of the deformation of surrounding rock around cavern,the expansion the dilatancy property of rock mass is considered,according to different plastic condition,the non associated flow rule is adopted to discuss the elastic-plastic of surrounding rock of underground cavern,and combined with the actual engineering example is analyzed,it is concluded that the increase of softening modulus can directly lead to the decrease of the tangential stress and the increase of radial stress of surrounding rock.And the softening modulus increases,the residual area and the softening radius will increase in different degrees.According to analysis the influence of the shear expansion of rock mass on the displacement of surrounding rock,and compared with the different failure criterion.The results obtained by the proposed solution indicate that,the Hoek-Brown criterion is better than that of Mohr-Coulomb criterion.In a word,this paper can provides theoretical basis and reference for the systematic study of the deformation and failure characteristics of underground chamber and the actual support technology.Therefore,the research of this paper has important engineering significance and scientific value.