Bed separation will cause anchor to generate additional stress

when the deformation of surrounding rock of roadway is uncoordinated. Based on the existing elastic analysis

an elastoplastic mechanical model of the bolt additional stress caused by the further expansion of the bed separation is established. According to the bolt pulling load to the bolt function mechanism during the relative movement of the strata

through the selection of two-stage linear function shear slide model

the sliding range in both left and right sides of the bed separation is determined; and the stress distribution mode of the anchored mass under the bed separation effect is obtained. Loading process of the anchored mass under the bed separation function is general divided into four stages

i.e. elastic stage

one side into elastoplastic stage

both left and right sides into elastoplastic stage and another side sliding larger with one side sliding all. By means of the parameters analysis of different separation values and different separation locations

the analysis finds that under the condition of the same bed separation location

the larger bed separation value

the larger the additional stress occurred from the bolt by the bed separation would be. Under the condition of the same bed separation value

elastoplastic stage basic trend and elastic stage trend are same

which presents as the stress at the center of the bolt would be minimum; the additional stress occurred close to the boundary bed separation would be larger.