Study On The Characteristics Of Gebi Soil Foundation Of High-speed Railway

The area,where the second LanXin line lies,has very compli-cated and special geological and geographical environment.This line locates locked areas in the west china.It is influenced by landlocked-arid,and aridsol exist along this line.The type of soil in desert lan-dform is Gebi soil,chiefly.So far,there is not enough research on t-he physical-mechanical and deformation properties of Gebi soil.Esp-ecially,the research about enginering properties of high-speed railway subgrade is too shallow to meets the demand of subgrade constru-ction of high-speed railway,which main index is settlement control. Therefore,the study on the characteries of foundation of Gebi soil of high-speed railway is necessary.This paper relies on research program—the key technology s-tudy of high-speed railway subgrade of Gebi area.and the Gebi soil exist along the second Lanxin line is regarded as object of study. T-hrough the collection of former material,site investigation,experiment and laboratory analysis,the geological environment of Gebi soil alo-ng the line is in hand.Using the analysis of causes of geological h-istory,the formation mechanism of Gebi soil is investigated;Accordi-ng to field investigation and related laboratory tests,the physical-mec hanical properties is analyzed,and experience relationship which bas-ed on loading test between different field test index and characteris-tic value of subgrade bearing capacity ordeformation modulus are determined;Through the results of ponding loading test,the wetting deformation properties of crushed gravel soilin Gebi area is research ed. And the collapsibility about this kind ofsoil is also judged.Base-d on experience relationship between coeffic-ient of collapsibility a-nd parameters about desity of soil or materialcomposition under dif-ferent depth,the vertical change law of wettingdeformation about G-ebi soil is analyzed.At the sametime,using results of SEM,the mech-anism of wetting deformation which based on micro-structure about Gebi soil is analyzed.Vertical law of coefficient of collapsibility in macroscopic view also is interpreted.At last,through the result of different foundation treatment a- nd its design parameters of the subgrade test section in different geological condition,especially comparative analysis on data about settlement of different foundation treatment,treatment method and its design parameters which base on settlement control for typical geol-ogical condition along the line is proposed.It can supply scientific basis for subgrade construction of high-speed railway in Gobi area in future.