Shaking Table Test Study On Seismic Response Of Dredger Fill Site With Thick Sofe Soil In Beibu Gulf

Sand blowing reclamation is currently one of the most widely used methods in sea reclamation.Compared with ordinary hydraulic reclamation sites,the hydraulic reclamation sites in the Beibu Gulf region have particularly complex site characteristics due to the underlying deep and thick soft soil.Under the combined action of the overburden load caused by the construction of engineering activities and the change of ocean tide level,the properties of the soft soil layer are in a process of continuous change,and the seismic response of the site is also in a process of continuous change.In order to explore the influence of the site conditions of the dredger-filled site on the seismic response,this paper uses a dredger-filled site as a prototype to simplify the construction The soft soil layer and the dredger-filled sand layer are the main rock-soil layer shaking table models.The reaction jack and the water level adjustment device are used to simulate the change of the dredger fill site subjected to the preloaded load and the change of the groundwater level.The dynamic response characteristics of the landfill model under earthquake action.The main research work and results are as follows:(1)Through field investigation and the summarization of a large amount of survey data,the analysis shows that the marine soft soil layer and the dredger-filled sand layer are the main factors affecting the seismic response of the dredger reclamation site.In the dredger reclamation site,a large amount of marine soft soil and dredger sand Sampling is used for shaking table model materials and measuring parameters.(2)A shear box based on the joint design of the research group,and a supporting design of a numerically controlled jack based on the principle of acting force and reaction force,and a device for adjusting the water level of the sand layer based on the principle of communicating device were used for shaking table test.Experiments verify that the shear box can better simulate the semi-infinite boundary conditions of the prototype site;the numerically controlled reaction jack can continuously load the model soil to simulate the compression state of the prototype site;the water level adjustment device can determine the water level in the sand layer.(3)The soil properties of the model site are changed by applying three-level loads of 10 kPa,20 kPa and 30 kPa to the model soil.The analysis results after excitation show that the hydraulic fill site has an amplification effect on horizontal ground motions,amplification effects and seismic wave spectrum characteristics Relatedly,after the load is applied step by step,the site amplification effect is attenuated,the shear model increases,and the site excellence period decreases;the excess pore water pressure in the sand layer is in a process of continuous accumulation with the increase of depth.After compressive loading,the pore pressure at the same depth showed a decreasing trend.The hydraulic fill site can effectively improve the stability of the site after it is stabilized by applying a pre-compression load.(4)Four gradients of sandy soil water level are set,and the analysis results after excitation show that: after the water level drops,the horizontal ground motion amplification effect of the hydraulic fill site attenuates,the shear modulus decreases,and the site's superiority cycle increases;sandy soil layer The internal pore pressure shows a decreasing trend after the water level drops,the probability of sand liquefaction decreases,and the site stability increases.