The Study On The Mechanical Interaction Of Anchor And Surrounding Rock

In the supporting of mine roadway,the popularity rate of bolting is close to 100%.But at present the theory of bolting support lags far behind the practice,empirical method and engineering analogy method still play important roles in the engineering.The essence of the bolting mechanism and prestress bolting are analyzed and summarized.The engineering practicability of the suspension theory and the composite beam theory is evaluated by calculating the exact case.Choosing anchor and the rock around the anchor is chosen as bolting unit to study,when the rock mass is broken because of the tension,the loading in ancor is low as a result of the differences between rock mass and anchor in mechanism.In order that the anchor makes full use,assume that the anchor reaches the yield point when the surrounding rock mass is failed,the anchor needs to be imposed high prestress and the prestress should be closed to the yield point.According to the relationship between the deformation of the rock bolt and the surrounding rock,the formula of the maximum prestress of the bolt is deduced.When study on the different anchors in strength,find that the anchor with high strength is the same as the anchor with low strength without prestress.The advantage of anchor with high strength does much better in supporting the failed rock and exposing higher prestress.In order to study the mechanical interaction between bolt and surrounding rock,and the elastic modulus of the rock mass anchorage are analyzed.The relationship between the anchorage length and anchoring force is gotten by analyzing the behavior of the unit of anchorage-body.FLAC3 D is used for comparing the function of different anchoring based on roadway roof subsidence,convergence of wall rockand volume of plastic zone.The result shows that higher prestress does better in controlling the deformation of surrounding rock.Then the result research is used in the support optimum in Dongdong mine,according to the monitor in scene,the roadway is controled well.