Shaking Table Test Study On A New Type Of Shock Absorption And Energy Dissipation Reinforcement System Under Strong Earthquake

With its suddenness,randomness and unpredictability,landslide geological hazards have gradually become one of the most serious geological hazards.Under the action of seismic load,unstable rocks are highly susceptible to collapse,leading to serious geological disasters and causing huge losses to human life and property safety,therefore,people pay more and more attention to the research of prevention and control technology of dangerous rock collapse bodies.The traditional active reinforcement techniques,represented by anchor rods(ropes)and anchor rods(ropes)anti-slip pile reinforcement techniques,are widely used because they are highly targeted and have excellent reinforcement performance.However,these traditional reinforcement techniques have disadvantages such as large stiffness and small adjustment of deformation(even cannot be deformed),which can easily be damaged or partially damaged under the reciprocal vibration load of earthquake,resulting in reinforcement failure.In view of the characteristics of traditional active reinforcement technology,this thesis discusses an active reinforcement system with seismic energy dissipation function.Two forms of seismic energy dissipation structures are mainly studied,reinforcement structure one is to replace the traditional anchor rod(cable)anchor head with a seismic energy dissipation anchor head,and reinforcement structure two is to replace the traditional support pile structure with a seismic energy dissipation and bearing pile.By means of a large shaking table physical model and ANSYS finite element numerical simulation,the two types of seismic energy dissipation reinforcement structures were tested for active reinforcement of dangerous rock masses under seismic conditions to explore the dynamic response and energy dissipation effects of the reinforcement systems of the two new types of seismic energy dissipation devices under seismic loads.The following main conclusions were drawn from the experimental studies:(1)For the sliding collapse damage mode,the mechanical parameters of the sliding surface are important parameters affecting the stability of the critical rock mass.The soft sandwich material in the test can be made by using five materials such as quartz sand,talcum powder,loess,glycerin and water through different ratios to.It is found that the content of quartz sand plays a controlling role on the angle of internal friction and the magnitude of cohesion of similar materials,while the content of talcum powder and loess has a greater influence on the cohesion and a smaller influence on the angle of internal friction;(2)The dynamic response of the reinforced structures under different seismic wave effects is different,and the energy dissipation effect of the damping and dissipation devices of both structures increases significantly with the increasing peak acceleration of the input seismic wave;(3)The acceleration of the rockfall with weak intercalation tends to enlarge on the dangerous rock mass after the seismic wave is input.The second damping energy dissipation device can reduce the horizontal acceleration increment by 60%and the supporting force of bearing pile by 97.17% In the first strengthening structure,the damping and energy dissipation anchor head can reduce about 27.5%horizontal acceleration increment and 71.3% tensile force(4)For reinforcement structure II,as the bottom of the support pile is connected to the stable rock mass and the top is connected to the seismic energy dissipation device,seismic waves are input from the top and bottom of the pile in two directions,resulting in the splitting and superposition of the seismic wave field in the pile body,causing the acceleration response of the bearing pile to show an "S" shape variation along the pile height.(5)The test results show that the two types of seismic energy dissipation reinforcement structures designed in this thesis have a good effect of cutting the peak energy of earthquakes and can greatly reduce the destructive force of earthquakes,and are expected to be applied in the reinforcement works of dangerous rock bodies in seismic areas after further summary and improvement by engineering trials.