Control mechanism and application of doubly supported roadways with large rigidity and high strength

Through theoretical researches and contrast testes on various support modes in mines,a viscoelastic,viscoplastic mechanical model for doubly supported roadway with large rigidity and high strength was established.Theoretical calculation,analysis,application of stability control of surrounding rock for the soft rock roadway supported by bolting and shotcreting the first support and the second support with large rigidity and high strength.According to the results of the theotetical calculation,the convertion of the stress state of surrounding rock before and after the setting of second support were analyzed;the theoretical viscoelastic and viscoplastic solution on the maximum operation resistance of the second support was obtained;the parameters of the second support with large rigidity and high strength were determined;the safe and reliable supporting method was selected;the long-term stability of the roadway was realized successfully.The mechanism of stability control of rock surrounding the roadmay with double supports was summarized as follows.With the pressure released by the first support,the support capacity of the rock mass was fully used,and its stress state would be in agreement with the low deformation rate.The high stress state and reduction of the bearing capacity of surrounding rock of roadways owing to the creep and strain softening was avoided by the second support with large rigidity and high strength.And then,the circumferential stress was decreased,the radial stress was increased,and the optimization stress state would be obtained.The rock mass stress was thus transformed into the long-term strength and stable state with the viscous deformation stopped.