Saline Soil Engineering Geology And Salt Expansion Characteristic Analysis And Evaluation In The Area Of Nong'an

County agriculture is located in the Midwest of Jilin province,in the central area of the SongLiao plain.Due to the low altitude is around and gently topography,and lead to poor drainage.Shallow groundwater mineralization degree is high,the water salt ions with the moisture migration,lead to soil salinization in this area is heavier.And is located in the typical seasonal permafrost regions in west Jilin,the winter cold,summer heat,the average annual evaporation capacity greater than precipitation,so the highway,railway,building,power stations and other water conservancy projects will be affected by the salt expansion-frost heave of saline soil.Hydropower station in west Jilin embankment toe,dam,the dam foot will be in season when salt expansion effect is obvious and severe frost heave effect when the winter,so these buildings will appear bloated phenomenon,wait until the spring of the second year in a civilized,appeared in harmony in deformation and failure,with the increase of evaporation,with salt water upward migration,cause spring pavement frost boil wait for a phenomenon.Therefore this study selected farmers Ann area saline soil as the research object,in different depth of soil sampling for indoor field basic experiment,study the engineering geological characteristics,composition and particle size for different depth in the soil of the composition and mineral composition,moisture content,density,plasticity index,soluble salt content,PH and organic matter,etc.The different engineering geological characteristics of the soil were obtained by the study of the interior experiments.Based on the design of the degree of compaction,moisture content and salinity of frost heave test,the paper further discusses the sulfate,carbonate under the condition of different single salt content and the salt content of the two different conditions,the change law of salt expansion and frost heaving soil sample.From the Angle of physical and chemical properties and compactness,water content and salt content,the mechanism of the variation and deformation of soil is discussed.1.In this study,the soil body is mostly powdery clay,and it is mainly used in the high liquid limit clay,and the dispersant has a certain dispersion effect on the soil in the area.The native mineral content of the soil is higher than the secondary mineral content,the primary mineral is quartz,and the clay mineral is mainly the illite and kaolin.2.Natural moisture content is between 20% and 35%,and decreases as the depth increases.The natural density is between 1.77 g/cm3 and 1.95 g/cm3,and the 50 cm depth is a turning point for natural moisture and natural density as the depth of the increase decreases first.Soluble salt is mainly sodium sulfate and sodium bicarbonate,and the content is not different.As the PH increases in depth,the soil is weakened by a weak base and becomes weak.At the depth of 0-110 cm,the cationic exchange volume is relatively small,and the cationic exchange is larger at 130-170 cm depth.The soil organic matter content is between 0.22% and 1.6%,and the maximum occurs at 150 cm and the minimum occurs at 60 cm depth.3.Frozen shrinkage properties of sample: sulfate sample under relatively low degree,when reduced to 0 degrees Celsius temperature,before the sample how much will appear some smaller,salt sample volume begins to increase after 0 degrees Celsius,salt-free sample after-5 degrees Celsius,and began to increase,when the compaction degree is higher,the sample volume is still at the start will shrink,but salt sample volume begins to increase after 5 degrees Celsius,high salinity samples even after 10 degrees Celsius have been increased,salt-free sample after 5 degrees Celsius-volume still began to increase;For carbonate samples and mixed samples,the positive temperature range,the sample was contracting,when the temperature continue to reduce,the sample will shrink,and under the low-pressure compaction degree of low moisture content,salt samples of swelling temperature significantly lower than the salt-free samples of swelling temperature,the high degree or low-pressure compaction degree of high moisture content,the sample of the expansion temperature at 5 degrees Celsius,and salt-free sample phase.4.Sulfate salt-frost heaving characteristics of sample: under low-pressure compaction degree,the sample of salt-frost heave rate increased with the increase of salt content increases,under the high pressure degree low moisture content,the sample of salt-frost heave rate does not change significantly with the increase of salt content,but high salt content under high moisture content,salt-sample frost heave rate with the increase of salt content increasing;Under the same salinity,when the compaction degree is bigger,the sample of salt-frost heave rate increased with the increase of moisture content increases,when the compaction degree is small,changing regularity is not obvious;In the case of salt content,the sample salt-freeze ratio increases with the increase of compactness5.Salt-frost heaving characteristics of carbonate sample: in certain conditions,the compaction degree of salt-containing salt sample frost heave rate is significantly lower than the salt-free sample of salt-the rate of frost heave,salt-containing salt sample frost heave rate is smaller with the increase of salinity change,under relatively low degree,low moisture content samples in the frozen state;The same amount of salt in the same amount of salt,the salt of the sample,increased with the increase in water content.Under the same amount of salt,the sample's salt-freezing rate increases with the increase of compactness.6.Samples of mixed salt-frost heaving characteristics: under low-pressure compaction degree,salt-containing salt sample frost heave rate is lower than the salt-free sample of salt-the rate of frost heave,salt-containing salt sample frost heave rate is smaller with the increase of salinity change,under the high pressure degree,salt-containing salt sample frost heave rate with the increase of the salt content increased slightly;In the case of a certain amount of salt,the salt of the sample is increased with the increase of water content,and the change of the low pressure is not obvious.Under the same amount of salt,the sample's salt-freeze rate increases with the increase of compactness.