Abstract：In the local or global movement of rock mass under mining，overlying strata play a key role. The overlying strata movement is a complicated space-time process and has time-dependent feature. Based on Burger model，the time-dependent feature of neutral surface of mid-thick soft rock plate under static load bending is studied by mid-thick plate model. The results show that the location of neutral surface of mid-thick soft rock plate will change with time in a long period and is affected by the stiffness and viscometric parameter of rock mass. For rock mass under mining，the support of surrounding rock mass in initial stage is critical to the stability of surrounding rock mass.
