Study On Creep Characteristics Of Q₂Loess And Its Effect On Slope

Loess is widespread in China, it has complex engineering properties for its specialsubstance components and complex structure, and the stress-strain relationship of it is closelyrelated to the time. With the sustained and rapid economic growth in China, an increasingnumber of projects in all walks of life are related to the loess. In order to ensure the safety ofthese projects, it has a very important theoretical and practical significance to study therheological characteristic of loess.Based on the analyses of a great number of related literatures about the loess creep athome and abroad, the author carried out conventional triaxial creep test on the Q₂loessindoors in Liquan area of Shaanxi province,and studied the creep characteristics of the loesssystematically and its impact on the slope combined with FLAC3D numerical simulation.The main contents of the research are as the followings:（1） According to the conventional triaxial creep test on the Q₂loess with three kinds ofwater content（ω=12%、16%、21%）under four kinds of confining pressure levels（100kPa、150kPa、200kPa、300kPa）in Liquan area, the author drawn the loess creep curve withdifferent water contents under different confining pressures, summarized its creep propertiesand analyzed the creep characteristics under the influence of the confining pressure.According to the test results and triaxial creep test curves, the author drawn a triaxial creepisochronous stress-strain curve, analyzed the loess creep stress-strain variation at differentconfining pressure levels, and explored the mechanism of loess creep.（2） By analyzing the riaxial creep test results and related creep test curves, the authorobtained two typical empirical model, the Singh-Mitchell creep model and the Mesri creepmodel, which can describe the creep characteristics of soil body, at the same time use themathematical methods to establish creep empirical model formula for the Q₂loess in Liquanarea and determined the relevant parameters of the formula. Based on the study of theconstitutive model for loess in Liquan area, the author selected the five parametersgeneralized Kelvin model to determine the correlation coefficient for the formula by fittingthe creep test curves and thereby established the creep theory constitutive model formula.（3） The numerical simulation of the Q₂loess in Liquan area was carried out using FLAC3D under Mohr-Coulomb model and generalized Kelvin creep model. Meanwhile theresults of the two models in different times were contrasted and studied to the other.