Shaking Table Test On Dynamic Damage Response Characteristics Of Pile Sheet Wall

In the railway engineering project,the retaining structure undertakes the important responsibility of maintaining stability of the slope and plays an important role in Aseismatic engineering.However,during the service period,due to the long-term earthquake load and various environmental erosion factors,the internal damage will inevitably appear in different degrees.When the damage accumulates large enough,the retaining structure may have unexpected failure,resulting in serious casualties and huge economic losses,and the major accidents caused by the sudden accidental failure of the retaining structure have been common.Therefore,it is of great significance to study the damage detection of retaining structures.The thesis relies on project of "Key Technologies Of Post-earthquake Service Status Monitoring And Evaluation Of Typical Retaining Structures In High Intensity Earthquake Area" of China Railway second Hospital Engineering Group Co.,Ltd.damage detection and identification of pile-plate wall slope retaining structure is mainly carried out through large-scale indoor shaking table model test.Compared with numerical simulation and traditional excitation test,a method closer to engineering is used for damage research and analysis,which provides some theoretical reference and guidance for damage detection in practical engineering.Through the research,this paper mainly draws the following understandings and conclusions:(1)The main contents of this paper are as follows:(1)the distribution law of pile displacement,soil pressure behind pile,pile strain and pile PGA in the service of pile-sheet wall and the change law after damage are analyzed.It is found that after the damage of the pile,the dynamic response will change suddenly,and the displacement at the top of the pile will increase suddenly,at the same time,the soil pressure behind the pile and the strain of the pile begin to decrease with the vibration,so that the real-time damage identification can be carried out when the earthquake occurs.(2)several different modal parameters(natural frequency,modal mode,modal energy)are used to identify the damage of the pile-sheet wall,and the changes of the modal parameters along with the damage are obtained.Several recognition methods are compared,and the advantages and disadvantages of each method are obtained.(3)due to the different damage locations of the three groups of tests,it is found that the damage near the Anchorage surface and the cantilever section of the pile develops faster than that of the Anchorage section.it has a greater impact on the retaining capacity and life.In the damage identification,the modal parameters are also more sensitive to the damage of the Anchorage surface and the cantilever section.(4)due to the different initial damage of the three groups of experiments,the residual retaining capacity of pile under different initial damage is compared and analyzed.it is found that the total energy of normal service(damage occurs or the original damage continues)decreases linearly with the increase of the initial damage degree,and the decreasing rate of the maximum bearing capacity of the pile will gradually accelerate with the increase of the initial damage degree.