Study On The Strength-Deformation Characteristics And Failure Criterion Of Heifangtai Q₃Loess By True Triaxial Tests And Finite Element Simulation

Loess is a type of special deposit which has characteristic of cellularity and bond. Itsforming period could be supposed to Quaternary Period. Loess is widely distributed in Asia,Europe, North America, South America, etc. In China, In different ancient terrace gravel layer,the Tertiary and Cretaceous strata, weathering and erosion surface has extensive unconformitycoverage. And it formed a typical loess landscape, mainly distributed in the Yellow River andin the upper reaches of the northwest of Gansu, Shaanxi, Ningxia, Shanxi and other provinces,autonomous regions.Loess is a structural soil, due to special causes and dry storage environment, it hassignificant structural strength and high bond strength, has not destroyed the ability of thebasic unit of structure to maintain the original soil in dry conditions. However, once theexternal force to interfere with or affected by water erosion, its mechanical properties willappear in the yield, softening, strength, disintegration, and collapsible characteristics. It isprecisely because of this characteristic of the loess, the loess areas are geologicaldisaster-prone. The practical significance of this paper is hoping to establish a rational Q₃loess constitutive relation, using the finite element software for accurate analysis of thecalculation of Q₃loess, and management data available for reference, for the loess areas ofconstruction and disaster prevention, saving construction costs, and improving the safety ofthe works.In order to study the loess, especially Q₃loess, a special type of mechanical properties ofsoil, I carried out up to six months of the true triaxial tests and ABAQUS Finite ElementAnalysis of the Heifangtai loess tableland area loess at various moisture content, confiningpressure and stress ratio of true triaxial tests, and confirmed the typical characteristics ofstrain hardening. And through the collation of data analysis, I found the friction angle of theHeifangtai Q₃loess shear strength having parameters functional relationship between axialstrain, which would contribute to established a more accurate Q₃loess constitutive relationand failure criterion with test data and new ideas, and this really have some practical value.After I used the ABAQUS finite element simulation software for Finite Element Analysis ofcalculation, confirmed that finite element analysis and calculation of modified Mohr-Coulombelastic-plastic model is suitable for Q₃loess. Finally, I provides some thoughts and ideas inthe conclusions of the analysis and prospects for the next Q₃loess full stress-strain simulationanalysis.