Research On Wave Dissipation And Energy Absorption Characteristics Of Different Boundary Materials Under Static-Dynamic Coupling Loading

With the gradual extension of resource exploitation to the deep in China,the deep engineering rock mass is mainly in the multi-field coupling environment of "three high and one disturbance",in which the deformation characteristics and mechanical response mechanism of the rock mass are quite different from those of the shallow part.Therefore,there is an urgent need to develop a deep multi-field coupled true triaxial dynamic and static rock loading technology to study the mechanical properties and failure law of deep rock mass.However,in order to meet the test requirements of the interaction of true triaxial loading and strong disturbance,it is necessary to find a suitable boundary material to be placed between the rock and the transmission end,so that the incident wave and reflected wave do not interfere with each other.In this paper,the experimental study on the wave dissipation and energy absorption characteristics of many kinds of materials under the condition of dynamic and static combined loading is carried out by using the improved SHPB dynamic and static combined loading device,and it is concluded that the effect of wave dissipation metal plate is the best boundary material.Then the effects of parameters such as thickness and aperture of wave dissipation metal plate on the wave dissipation energy absorption characteristics of the material are analyzed by experiments,and the main conclusions are as follows:(1)Under the action of a single impact load,the weakening effect of the wave-absorbing metal plate on the stress wave is greater than that of the porous metal,and the compression wave reflected by the waveabsorbing metal plate has less influence on the rock rod.In terms of the overall law of energy dissipation,the energy absorption rate of waveabsorbing metal plate and porous metal with higher wave impedance is higher,which plays a certain role in weakening energy reflectivity.(2)Through the cyclic impact tests of different boundary materials,it is found that the repeatability and fatigue resistance of porous metals are not as good as that of wave-absorbing metal plates,and the peak stress and energy reflectivity of wave-absorbing metal plates increase with the increase of impact times.the energy transmittance decreases with the increase of impact times,but the range of change is not obvious.To sum up,the wave absorbing metal plate is the best boundary material.(3)Through the dynamic and static combined loading test of wave absorbing metal plate with different thickness and aperture,it is found that the peak stress and reflectivity of wave absorbing metal plate decrease with the increase of pore diameter and thickness,and the energy absorptivity increases with the increase of thickness and aperture.The change trend of energy reflectivity and energy absorptivity is opposite,and the energy transmittance of wave absorbing metal plate fluctuates in a stable range.The change range is not obvious relative to the energy absorption rate and reflectivity.