Study On Deformation Characteristics And E-lgp Curve Prediction Model Of Compacted Loess

Northwest China is located in the Loess Plateau,where mountains and gullies are widely distributed and the terrain fluctuates greatly.In view of such special terrain conditions,in highway transportation construction,the roadbed often adopts the form of high embankment.In the construction of loess high embankment,dynamic compaction,heavy hammer compaction and other methods are often used to compact the fill,and the corresponding compaction work has exceeded the standard heavy compaction work.The change of compaction work will change the compaction state of the soil mass,and the compression characteristics of the soil mass will change accordingly,which will directly affect the compression deformation of the subgrade itself.In addition,the indoor compression test has a large number of loading stages and a long loading time.When the compaction power used in the field construction is changed,it will take more time to carry out the corresponding compaction power test.At present,the research on the compression deformation characteristics of loess under super heavy compaction work in a wide range of water content is insufficient,and the research on the prediction method of compressibility index after the change of compaction work is less.Taking loess as the research object,this paper studies the compaction characteristics and deformation characteristics of loess under the action of standard and overweight compaction work in a wide range of moisture content,and puts forward the prediction method of soil e-lgp curve after the compaction work changes.The main work of the thesis is as follows:（1）Carried out particle analysis test,specific gravity test and limit moisture content test on the loess taken,and named the loess taken according to relevant specifications.The results showed that the test material belongs to low-liquid limit sandy silt loess.（2）Two standard compaction power（light and heavy）and two super-heavy compaction power tests were performed on the loess taken within the full water content range.Based on the four parameter equation of full compaction curve,the variation law of full compaction curve after exceeding the standard heavy compaction work is analyzed;The relationship between the matrix suction and the compaction work at the compaction sensitive threshold is studied,and the empirical formula between the matrix suction and compaction work was obtained,which provides a new method for determining the moisture content of the compaction sensitive threshold.（3）One dimensional confined compression tests were carried out on compacted soil samples,and the deformation characteristics of the samples corresponding to four kinds of compaction work in the range of total water rate were obtained.Analyzed the law of the compression modulus E_s1-2 with the moisture content,and obtained the mathematical model between the compression modulus and the moisture content.Analyzed the relationship between the model parameters and the physical indicators;Based on this,the change curve of compressive modulus with water content after the change of compaction work was estimated.（4）The variation law of e-lgp（e-p）curve under different compaction work was analyzed.Slogistic function was used to fit the e-lgp curve,and the relationship between function parameters and physical indexes was determined;Based on slogistic function model,a new method was proposed to predict e-lgp curve under different compaction work based on compression modulus E_s1-2 and initial void ratio e₀.