Numerical Simulation Study On Deformation Law Of Deep Roadway Surrounding Rock Under Multi-field Coupling Effect

As coal resources have developed into deep stage, the geological conditions deteriorated, and ground stress, geothermal gradient and pore-pressure increased significantly.It is not just the high ground stress but the multi-coupling effect should be considered to exipain characteristics of roadway deformation.By using the finite difference software FLAC3 D, this paper stimulates and analyzes the deformation and destruction characteristics of roadway under multi-field coupling effect, providing some references for roadway stability analysis and support design. The major research and results are as follows:First, through numerical simulation on temperature field distribution of deep roadway surrounding rock, this paper summarizes the law of rock temperature field variation with time after tunnel excavation.And it discusses the factors which can affect the rock temperature field distribution, the result shows that the greatest influence is airflow temperature, roadway radius followed, the smallest is cross-section shape.Second, through numerical simulation on surrounding rock deformation law at depth under thermo-mechanical coupling, this paper obtains that compared to the case without considering temperature, when considering the thermo-mechanical coupling effects, the rock loosening zone, displacement, the volume of the plastic zone and the axial forces of bolts and anchors all increased and the axial force increase as much as 10.9kN.Thermal stress acts as tensile stress, and it causes the tensile failure volumes increase at the roadway wall.The bigger the temperature difference value between roadway temperature and airflow temperature, the greater the tensile stress, displacement and plastic zone increased.Third, through numerical simulation on surrounding rock deformation law at depth under fluid-solid coupling, it obtains that with the increase of initial pore-pressure, the loosening zone, displacement and the plastic zone volume of surrounding rock increase, too.When the initial pore-pressure is low, they increase slowly; otherwise, they increase significantly. The support structures alter the distribution of stress field, and then they influence the process of coupling effect between stress field and seepage field.Forth, through numerical simulation on surrounding rock deformation law at depth under fluid-solid-heat coupling, by non-completely coumpling analyse, the coupling effect act as ground stress, geothermal gradient and pore-pressure transform into stress variation loaded in the surrounding rock, which leads to the rock stress viaration range, displacement and the plastic zone volume increased significantly.