| With the proposal of the strategic deployment of "maritime power",the strategic status of the South China Sea has also been improved,and China will deploy a series of important infrastructure construction in the South China Sea.In the process of project implementation and operation,the nature of the foundation soil has a great impact on the quality and stability of the building,and coral sand,as one of the representatives,has the properties of large porosity,large compressibility and easy crushing of particles.In the field of geotechnical engineering,there has not yet been a constitutive that can better simulate its physical and mechanical properties;moreover,because the coral sand foundation is located in the South China Sea,the water content in the soil pores is high,and the seismic effect is very frequent,so at the numerical simulation level,the development of a water-soil coupling unit that can describe the hydrodynamic reaction of the coral sand foundation has important practical significance.To this end,the work of this article will begin in the following aspects:1.According to the U-W theoretical formula,based on the secondary development of the element in the finite element software ABAQUS,a three-dimensional water-soil coupling element program was developed.The program can overcome the defect that the software can not deal with the dynamic and saturation problems at the same time,and applied a step load to the saturated model,which verified the correctness of the developed program,and pointed out that there was a coupling effect between the solid and the fluid;,which was different from the element in U-p format,so the permeability coefficient of an element at the boundary was set to a minimum value to simulate the undrained boundary,and the saturated soil under the action of the step displacement was successfully simulated,and the compression wave was predicted.At the same time,the influence of permeability coefficient on the coupling between solid and liquid was studied;in the process of applying impact load,it can be obtained that the stress and displacement inside the soil were transmitted in the form of waves.Therefore,it showed that the U-W water-soil coupling element program developed in this paper had the ability to simulate the dynamic seepage coupling analysis of saturated soil.2.The simulation of the triaxial consolidation undrained test of rockfill based on the generalized plastic model showed that the results were consistent with the experimental results,and the simulation results of the cyclic loading test conformed to the general law.The simulation analysis of the bearing capacity of the coral sand foundation showed that the bearing capacity of the broken coral sand foundation was low,and it would produce a large settlement under the same load;plateau and slow growth,which was related to the phenomenon of particle breakage.The loading process of coral sand foundation was a process of gradual compression,fragmentation,compaction and compaction,which led to the settlement of coral sand was larger than that of ordinary sand,and the bearing capacity was lower than that of ordinary sand.At the same time,when the particle breakage was considered,the range of soil failure increased,because the particle breakage affected a wider range of soil during the gradual sinking of the foundation. |
