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Study On Strength And Deformation Characteristics Of Unsaturated Soil In Seasonal Frozen Region

Posted on:2022-09-08Degree:MasterType:Thesis
Country:ChinaCandidate:X R YangFull Text:PDF
GTID:2480306530958249Subject:Geotechnical engineering
Abstract/Summary:PDF Full Text Request
Seasonally frozen soil areas are mostly in arid and semi-arid areas,which leads to seasonally frozen soil areas.The construction is more urgent and difficult.The soil at each construction site in the seasonally frozen area not only undergoes seasonal changes.Therefore,the soil has undergone many freeze-thaw effects.,which has brought difficulties to our construction.The fundamental reason for the changes in the properties of soil is that freezing and thawing have changed the structure of the soil,making the structure of the soil changed or even reorganized.In order to study the root causes of these changes in soil properties.Using the laboratory's unsaturated soil direct shear instrument and unsaturated soil consolidation instrument,Explore the changing laws and influencing factors of the strength and deformation of unsaturated soil after freezing and thawing.The specific research content and conclusions are as follows:(1)First,the basic physical mechanical properties test of unsaturated soil is determined from the particle level of the soil to determine the maximum dry density and optimal water content of this soil,and measure liquid limits and plasticity value.And based on this is based on the basis.(2)Drawing of soil characteristics curves.When drawing a soil characteristic curve,it is necessary to consider the relationship between the soil water content and the substrate suction of the soil of unfrobing and freeze-thaw.(3)Using an unsaturated earth-cutting with unsaturated and multi-free bails,it has been discipured,and the relationship between the number of freezers and shear strength is explored.In order to explore more inwardly,The gray Verhulst predictive model predicts the holding of the non-saturated soil and the shear strength of the shear strength,and the water content after 25 freeze-thaw cycles has almost no longer changing(the change rate is less than 0.5%),indicating that 25 times is the soil turning point of water content in the water is overweight,and this point can be utilized to provide a certain reference for local construction design.(4)Based on the structural parameters to the sensitivity evolution law of suction,the evolution of unsaturated dirt-specific parameters is established,and the same function model as the evolutionary law is equipped with the measured data,and the fit results are very reflected.Different degrees of freeze-bearing injury and the change of unsaturated soil shear strength under different matrix suction.(5)Using unsaturated soil solid-tunnel to carry out unsaturated soil compression test,in order to synthesize the effect of frozen merger on unsaturated soil compression characteristics,the concept,unsaturated dirt,the beginning of the initial experience The frozen structure is reduced,With the increase of freeze-thaw cycles,the freeze-thaw structure decreases.To characterize the effect of matric suction on soil compressibility,the definition of the suction compression coefficient in the literature Improvement,using the absorbing compression coefficient MS syndrome to characterize the matrix suction on soil compression characteristics.
Keywords/Search Tags:seasonally frozen soil, unsaturated soil, structural potential of freezing and thawing, strength, deformation
PDF Full Text Request
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