Experimental Study On Grain Size Composition Of Sandstone (D₂h) And Mudstone (N) Residual Red Soil In Kunming Changshui International Airport

Literate is distinguished from ordinary clay soil by its special physical,hydraulic andmechanical properties.With the rapid development of the national economy,engineering construction in the laterite distribution areas is increasing day by day.The engineering properties of laterite have an increasingly prominent impact on the safety and stability of engineering construction..The red mud in Kunming Changshui Airport is extensively developed.The genetic types and engineering properties of laterite are more complicated.In the past,the classification of laterite caused by the weathering of mudstones such as mudstone and sandstone was named“laterite”and there was no scientific explanation of the genetic types.Engineering characteristics,resulting in some defects in the survey results.Laterite has a granule structure,which makes it show a natural density,natural water content,saturation,porosity,liquid limit,high plastic limit,resulting in laterite in the physical and hydraulic properties with soft soil characteristics The characteristics of sandy silt in mechanical properties are also reflected.Therefore,the engineering properties of laterite are mainly factors such as the size of aggregates and the number of aggregates formed in aggregates.Therefore,it is of positive significance to classify and classify laterite.Studying the dynamic strength characteristics of different types of laterite will provide important reference value for seismic design of earthquake-prone areas.This paper mainly analyzes the profile characteristics and chemical mineral composition of the residual red rock of the two types of sandstone?D₂h?and mudstone?N?in the Kunming Changshui International Airport site.Based on this,a systematic and in-depth experimental study was conducted on the dispersion of sodium hexametaphosphate,sodium silicate,hydrogen peroxide,ammonia,sodium oxalate,sodium carbonate and other dispersants under different concentrations,and the residual sandstone?D₂h?was determined.The characteristic values of grain size components of red mud and laterite?N?.Aiming at the properties of the two types of laterite and the earthquake intensity in Kunming area,further experimental studies were conducted on the dynamic characteristics of laterit.Particle size component test study:The dispersive effects of the six dispersants are increasing within a certain range as the concentration increases.When the concentration rises to a certain number,the dispersion effect shows a downward trend;the sandstone residual laterite uses a concentration of 2.5%silicic acid Sodium as the dispersant achieves the best effect,and the mudstone residual red earth uses the concentration of 5%-8%sodium hexametaphosphate as the dispersant to achieve the best dispersion effect;the above dispersant concentration value reaches the peak value than the standard recommended concentration value The peak value is large,indicating that red clay is different from general clay soil in grain size composition and should be distinguished as special soil.Dynamic strength study:The dynamic parameters of laterite suitable for the earthquake characteristics of Kunming area were obtained.It is concluded that the dynamic internal friction angles of the two kinds of laterite dynamic shear strength increase gradually with the increase of the consolidation ratio,while the dynamic internal cohesion decreases gradually.The damage dynamic strength decreases as the consolidation ratio increases,and the consolidation confining pressure increases.