Salt-frost expansion characteristics of salt gravel soil embankment under progressive cooling conditions
In order to explore the salt-frost heaving deformation and characteristic temperature of sulfate containing embankment fill material of gravel mixture under the influence of multiple factors,based on three kinds of samples,namely,natural grading,particle size grading greater than 60 mm,and adding 5％fine particle(mass fraction)grading,salt-frost heaving tests and freezing temperature measurement tests were carried out under three water content and seven different salt content conditions.Combined with PFC3D numerical simulation,the effects of particle size distribution,water content and salt content on salt frost heave deformation and freezing temperature of gravel saline soil foundation were investigated.And the mechanism of action was also revealed.The results show that the freezing temperature of gravel mixture containing sulfate is mainly affected by the equivalent sodium sulfate mass percentage concentration corresponding to the soil salt content and water content.Due to the comprehensive influence of the cooling mode of the test and the low water content and salt content of the sample,the supercooling temperature of the soil sample could not be monitored in the test.The macro salt expansion temperature of the gravel mixture containing sulfate in the road base is lower than the freezing temperature,and the freezing temperature of the sample with 5％fine grained soil content is slightly lower than the other two samples.The freezing temperature range of the three samples is-1.58 ℃ to 0 ℃.The overall salt-frost heave rate of soil increases with the increase of salt content and water content.The salt-frost heave rate of soil without the gradation of particles larger than 60 mm,which is not much different from that of natural gradation.The addition of 5％fine particles can increase the salt-frost heave rate of soil by 3％to 30％,and the degree of improvement is affected by water content and salt content.The 5％content of fine particles fills the large pores in the sample,reducing the pore volume,and it is significantly sensitive to the salt frost heaving of the gravel mixture containing sulfuric acid in the embankment.The content of fine soil in the filler should be strictly controlled in the road embankment filling project.3 tabs,16 figs,26 refs.
road engineeringembankment fill materialexperimental researchgravel mixturesalt-frost expansionfreezing temperature
NETL
NSTL
万方数据
维普
