The Test Study Of The Structure Character Of Aeolian Soil In The West Area Of Liaoning And The Evolvement Regularity Of Structure Character During Freezing And Thawing

All kinds of basic physical and mechanical indexes are gained by doing a series of indoor conventional soil mechanics tests ,including density,water ratio,specific density,particle-size analysis ,consolidation and shearing tests.This creates condition for the following experimentation and theory analysis.By studing the arrangement and connection character of the undisturbed soil particle and the macroscopical mechanical property of the disturbed soil and the saturated soil,using the electronic microscope to observe the soil samples,comparing the aeolian soil in the west of Liaoning area to other areas,the unique structure characteristic of the aeolian soil is opened out. The compression coefficient indicates that the displacement of the undisturbed soil sample is the smallest ,the disturbed soil is next and the saturated soil sample is the biggest under the same pressure .This is mainly because the undisturbed soil is not disturbed so that the arrangement and connection are not damaged,yet the original structures of the disturbed soil and the saturated soil are damaged and it is the macroscopic reflect of having obvious structure character. The shape of the e-lgt curve are different obviously:with the increase of the pressure ,the division of the primary consolidation and the secondary consolidation becomes obviouser firstly and then becomes not obviouser.It is different greatly with the saturated soft clay . Using synthesized structure potential as structure parameter to compare the aeolian soil in Fuxin with the soil in Lanchow and Weifang,the result shows that they have marked difference.Moreover,the difference between the pictures which are gained by observing under electronic microscope and the microstructure pictures in other areas reflects the characteristics of dense structure and high strength.The typical aeolian soil samples in the western area of Liaoning province are frozen and thawed by using the improved freezing-thawing device. The test results indicate that the maximal swelling magnitude and thaw collapse value decreased with the increase of the temperature gradient;Not only in the closed system but also in the open system,the external force suppressed the swelling,the thaw collapse value also decreased with the increase of the load;The external water supply will increase markedly the ultimate swelling magnitude and thaw collapse value.After freezing and thawing,the pore feature of the soil changed obviously.This change inevitably leads to the variation of the frame feature correspondingly and makes the structural system of delivering power frame creates internal displacement so that the structure was changed. After freezing-thawing,the cohesive strength part of the shear strength decreased and the friction force part increased,that is internal friction angle increased. This is consistent with the result of the increase of contact point between the soil particles and the irregularity of arranging which is caused by the pore change.The ice efficiency is used as structure parameter and the structure evolvement regularity of aeolian soil is illustrates by studing the change with the water field and the stress field during the perild of freezing and thawing.