Experimental Research On Consolidation Properties Of Loess Based On Soil Water Characteristic Curve

The focusing topic of this paper is the consolidation of unsaturated undisturbed loess.This paper analyses the contraction、compression and collapse under the fluence of matrixsuction and net normal stress by measuring the soil water characteristic curve、one-dimensional contraction curve、one-dimensional consolidation curve、 coefficient ofcollapsibility curve and triaxial collapse volume change.Have achieved the following results:(1)The matric suction tests are made on undisturbed loess in Yan′an Shan xi provinceand the soil-water characteristic curve was fitting by V-G model. As is shown in the results,the change of suction in loess is closely related with occurrence of water in soils (consistencycondition) and the force of particle-scale, showing a law that the matric suction increases withthe decreasing of water content,however the slope is changing with the watercontent.According to the change of the slope,the soil water characteristic curve is dividedinto different stages, each stage of the boundaries of critical water content has a goodcorrespondence with soil limit water content.(2)The shrinkage test was taken, the test results show that the soil will yield only with theeffect of matrix suction.(3)The one-dimensional compression experiment of different water content wastaken,the results show that the structural yield pressure increase with the increase of thematrix suction, the greater the matrix suction, the lower the compressibility, the longer theelastic-plastic degeneration stage, the larger net normal stress will be needed for compressionstability.(4)The parameters of the constitutive equations was fitted with the data ofone-dimensional compression test, the results show that the Unsat-6constitutive equation isthe best fitting for the experimental data.(5)One-dimensional collapse test and triaxial consolidation test of different water contentsoil was taken, the results show that the collapsibility is closely related to the water content,the influence of water content on soil mainly through the matrix suction, cementation of (6)flexible rubber adherend between particles,soluble salt and soften of cohesion grain,the higher the water content, the smaller the coefficient of collapsibility and collapsibledeformation is smaller.(6)The parameters of Barcelona Basic model is fitted with the data of triaxialconsolidation test.The collapse strain calculated by the constitutive equation is almostconsistent with the test results.