Experimental Study On Strength Properties Of Compacted Loess

Yan’an belongs to the typical loess hilly-gully region.Stability analysis of high-stackedslope still has no mature experience which can be learned in the construction about NewDistrict of Yan’an.On the strength of compacted loess experimental research is veryimportant.In the study area,undisturbed loess is yellow or brown yellow which hasdevelopment vertical joint,high silt content,low natural moisture content and poor drydensity.By means of compaction test,it shows that the optimum water content is16%and themaximum dry density is1.85g/cm3.When the rest of the external conditions is quantitativeand the sample does not meet the maximum dry density,the compaction of the dry density ofspecimen increases with greater energy of compaction.Dry density of the sample closer to themaximum dry density,the more required energy of compaction to increase the units of drydensity of the sample.This paper uses SEM technology for microstructure scanning.For different dry density ofcompacted loess image display:Average pore diameter decreases with the increase of drydensity;The relative area of pore decreases with the increase of dry density of compactedloess;And dry density change caused that soil particles are arranged in the form of change.Itproduce certain effect to strength of compacted loess.According to the results of shear strength test from the different moisture content and drydensity,it can be drawn that the angle of internal friction and cohesion increase with theincreasing of dry density for compacted loess if the moisture content is under the sameconditions.The angle of internal friction and cohesion increase with the decreasing ofmoisture content for compacted loess if the dry density is under the same conditions. Andunder the state of saturation, cohesion tends to disappear.Application of unsaturated soil theory reveals the relationship between strength and thematrix suction and microstructure of compacted loess.Research shows that particlearrangement is gradually from the simple cubic arrangement to a tetrahedral arrangement withthe increase of dry density.The change of microstructure influences compacted loess strengthgreatly.It shows that the shear strength of compacted loess increases with the dry density increases performance of compacted loess, and decreases with decreasing matric suction(increasing moisture content).