Experimental Study On New Energy Dissipation Reinforcement Structure For Dangerous Rock Mass Under Strong Earthquak

Our mountainous area is vast,accounting for 69.1% of the total area of our country,dangerous rock mass often exists on the mountain slope,when the earthquake comes,dangerous rock mass is extremely vulnerable to disturbance and collapse disaster,causing serious damage to buildings,railways,roads,water conservancy facilities and human life and property safety,so the reinforcement support of dangerous rock mass is also getting more and more attention.The dangerous rock mass support technology can be divided into active support and passive support.In the active support,the current support technology,whether it is anchorage,supporting column and the combination of the two are rigid support,its stiffness is generally large,almost no deformation coordination ability,easy to be destroyed by small displacement under the reciprocating load of earthquake.Therefore,for the active reinforcement technology research on a new support structure with deformation coordination ability,under the action of the earthquake to allow deformation,through deformation to consume seismic energy,to achieve the purpose of peak shock absorption,energy dissipation shock absorption,at the same time the structure can greatly reduce the geometric size,economic and practical.The research has important engineering practical significance for the reinforcement and support of dangerous rock mass in earthquake area.In view of the understanding of active support,this thesis designs a new energy dissipation reinforced structure of dangerous rock mass and carries out a physical model test of shaking table,and uses numerical analysis method for comparison and verification.Through a series of experimental studies,the following results are obtained:(1)The dangerous rock reinforcement structure system with ordinary prestressed anchor rod(cable),shock absorber and energy absorber and supporting pile is designed.In this structure,shock absorption and energy dissipation device and supporting pile are added on the basis of conventional prestressed bolt(cable)support.When the bolt(cable)is deformed and destroyed under the action of earthquake,the impact force of dangerous rock mass will act on the shock absorption and energy dissipation device,which is supported by supporting pile.Through the deformation of shock absorption and energy dissipation device,the peak energy of earthquake can be effectively reduced.It provides a guarantee for the safety of dangerous rock mass under medium and large earthquakes.(2)Using shaking table test,by loading three kinds of seismic waves of multi-magnitude(El Centro wave,Wolong wave and artificial wave),the performance of the new reinforced structure of dangerous rock mass is tested.In order to effectively explore its structural performance,the test also sets a comparison test under the condition that dangerous rock mass is supported by ordinary bolt.The experimental comparison shows that the PHA amplification coefficient of dangerous rock in the common supporting structure group(control group)is greater than that in the new reinforced structure group(reinforcement group),which indicates that the new shock-absorbing and energy-dissipating reinforced structure has an obvious effect on weakening the acceleration of dangerous rock.(3)The monitoring of the impact force of dangerous rock shows that,under the action of earthquake,the impact force of dangerous rock on the new reinforced structure after the failure of the anchor bolt is far less than that after the failure of the ordinary supporting bolt,which indicates that the new energy dissipation reinforced structure can reduce the impact force of dangerous rock.(4)The experimental results show that the sliding surface of the new energy dissipation reinforced structure and the failure time of the bolt are delayed compared with that of the ordinary bolt supporting structure,which indicates that the dangerous rock can be displaced in a small range of the new energy dissipation reinforced structure through the hysteretic performance of the shock absorber and the tension of the bolt,so as to make its failure time lag,prolong the service life of the supporting structure and increase its overall safety.(5)ANSYS Workbench was used to establish a finite element model,and the acceleration response and displacement response were analyzed.The calculated results were basically consistent with the test results,which verified the accuracy of the model for the new energy dissipation reinforced structure.