Study On Creep Mechanics Characteristics Of Remolded Loess Under The Tensile Or Torsion Stress And Its Coupling Effect

The discussion of long-term stability mechanism of loess slopes with large gradient or even the vertical ones is the researchable emphasis of slope stability in the loess area.This is because that the top of loess slope exist tensile stress zone,and also exist torsional shear stress area in the complex stress state conditions.-Therefore,in order to explore the mechanism of long-term stability of loess slope,carrying out the remolded loess sample and conducting uniaxial tensile creep test,pure torsional shear creep test and tension-torsion coupling creep test have important theoretical significance.Based on the multifunctional triaxial creep testing machine with soil body pulling,pressing,twisting and shearing functions which was developed by ourselves,two types of remolded loess samples with the moisture content of 10%and 20%have been used to research the creep characteristics in this paper.The research of the creep characteristics are conducted respectively with uniaxial tensile creep test,pure torsional shear creep test and tension-torsion coupling creep test of remolded loess.The conclusions are as follows:1.Developed the new instruments which can study the creep mechanical characteristics of remolded loess,and can used to the study of creep characteristics of remolded loess samples with pure torsional shear creep test and tension-torsion coupling creep test.2.Based on the research of uniaxial tensile creep test of remolded loess,the law that tensile strain grow with time was discussed when the remolded loess under the uniaxial tensile creep effection,and hyperbolic equation of the tensile strain time creep characteristic curve of remolded loess samples has been proposed,3.Based on the research of pure torsional shear creep test of remolded loess,the law that shear strain increases with time was discussed when the remolded loess under the pure torsional shear creep effection,and Hyperbolic equation of the shear strain time creep characteristic curve of remolded loess samples has been proposed.4.Through researching of tension torsion coupling creep test of remolded loess,initially discussing the law that shear strain increaseswith torque of remolded loess samples under constant tensile stress.Hyperbolic equation of the shear strain-time creep characteristic curve of remolded lo ess samples in the case of constant tensile stress and different coupling torque load has been proposed.5.Through the research of creep test of remolded loess samples can be found that,the tensile creep of chemical adhesive can affect the uniaxial tensile creep test of samples when bondirng two ends of samples on the load mold with hemical adhesive,and then carrying out uniaxial tensile creep test of remolded loess,so it suggests that the creep duration should be less than 30 days in this study.