In the artificial freezing process of costal strata,the existence of underground water seepage with a high salinity will seriously affect the freezing range and freezing effect.In this paper,the Navier-Stokes equation is used to describe the momentum conservation of liquid phase in the seepage process of coastal strata,the adsorption and de-sorption effects of soil particle surface on salt during the seepage process and the influence of non-convective flux of liquid phase on the phase transition of water and salt during artificial freezing are taken into account,and a water-salt-thermal-mechanical theoretical model for the influences of seepage on the artificial freezing process of sand-clay stra-tum is established.Based on the software COMSOL Multiphysics,the water-salt-thermal-mechanical multi-field cou-pling theoretical model of sand-clay composite stratum under seepage conditions is solved,and it is found that the calculation results of the theoretical model are in good agreement with experimental results.Through a parameter analysis,the influences of different seepage velocities on the spatial distributions of water,salt,temperature and soil displacement are studied.Results show that as the seepage velocity increases from 0 m/d to 15 m/d,the difficulty in freezing the upstream soil in the sand-clay composite stratum also increases,resulting in a reduction of the up-stream frozen area towards the downstream and the downstream frozen area expanding downstream along the seepage direction.In the sand and clay layers,the leading-edge positions of ice move downstream by 60.3%and 26.2%,and those of salt crystallization move downstream by 50.4%and 26.2%,respectively.Under the action of phase changes in water and salt,an increase in the internal stress of soil leads to a growing soil displacement,and the clay layer's peak displacement increases by 107%after artificial freezing in the downstream of the sand-clay composite stratum.The influencing range of a freezing pipe in the direction perpendicular to the seepage direction is reduced.The values of temperature of clay and sand layers at a position of 0.3 m away from both sides of the freezing pipe are reduced by 1.1℃and 2.8℃,respectively.In the clay and sand layers,the total salt contents increase by 8.5%and 7.4%,while the ranges of ice generation are reduced by 10.2%and 54.9%,respectively.The research results in this paper pro-vide a theoretical basis and data support for artificial freezing construction in coastal strata under seepage conditions.
artificial freezingfreezing pipeseepagesand-clay composite stratummulti-field coupling theory
维普
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