Mechanism Analysis of Time-space Tendentiousness of Delayed Rockburst in Horizontal Rock Tunnel with High In-situ Stress
Delayed rockburst occurred frequently in HangWen Railway's horizontal rock tunnel in Zhejiang Province,but there are few studies on its gestation mechanism and space-time tendentiousness.Therefore,taking the time-dependent deformation of tunnel surrounding rock induced delayed rockburst as the core,the characteristics and mechanism of delayed rockburst were studied and analyzed by means of in-situ stress test and statistical field rockburst data.The results show these as follows.Delayed rockburst has obvious time-space tendentiousness characteristics.Nearly 70％of the delayed rockburst occur in the excavation of 6～30 days in this area,and lag the palm faces of 30～100 m in space.The delayed rockburst mostly occurs in medium rockburst,and the rockburst grade and possibility show an inverted"V"trend with time and space.Hard rock has obvious ductility and time-dependent deformation characteristics in high in-situ stress environment.Under unloading conditions,the stress releasing rate is the most important factor inducing delayed rockburst.After a certain distance of excavation,strain energy mutations occur at different locations around the tunnel,and a high strain energy density is maintained,which is prone to high-level rock burst.The above results provide a basis for predicting delayed rockburst and applying corresponding supporting measures in the future.
horizontal rock tunneldelayed rockbursttime-space tendentiousness mechanismin-situ stress testnumerical simulationelastic strain energy
NETL
NSTL
万方数据
