Optimum calculating method for constant resistant supporting of roadway surrounding rock

According to the creep mechanism of rock and surrounding rock and the control principle for rock creep,a new critical principle for steady creep of rock was put forward,and an optimum method for calculating the constant resistance supporting of roadway surrounding rock was set up based on experimental studies.Using the optimum calculating method,some important technical parameters could be determined,that is,optimum supporting force,allowable deformation of rock mass,cross section area of U-shape set,pre-tight force and diameter of the bolt as well as torque to provide optimum supporting force.The present method could make the supporting of roadway surrounding rock safe and economic.The latest experimental results of rock creep were used: the third invariant of deviator stress tensor had greater effect on creep properties;the stress threshold of lateral creep of rock was 20%⁴0% less than that of axial creep of the same rock.Their use made the design of roadway surrounding rock supporting safer.