Research On Creep Properties Of Q₂ Remolded Loess Under Different Water Content

The "Hill Cutting and City Building" project in Yan'an is the largest geotechnical engineering in the collapsible loess area in the world.Q₂ loess in Yan'an area is used as the filling site in most of the construction projects.Rheological property of loess is an important mechanical property of loess,and water content is one of the important adverse factors affecting the creep behavior of loess.Therefore,it is of great significance to conduct an in-depth study on the creep characteristics of remolded Q₂ loess from Yan'an under different water content.Conventional physical indexes,triaxial shear test,triaxial creep test and scanning electron microscope observation and analysis were carried out for remolded loess with different water content.The conventional mechanical properties,creep mechanical properties,constitutive model and microstructure of remolded loess were studied by means of mechanical analysis.The main conclusions are as follows:(1)The results of conventional triaxial shear tests show that the peak strength,cohesion c and internal friction Angle ? of remolded loess all decrease with the increase of water content.(2)Triaxial creep test results show that,under the same confining pressure,long-term strength ?? of remolded loess decreases linearly with the increase of moisture content.The relationship between long-term strength ?? of remolded loess,confining pressure ?3 and moisture content ? can be expressed as follows:??=(-29.1-21.4?3)?+1.53?3+479.4?(3)Compared with the traditional Xiyuan model,the calculated values of viscoelastoplastic rheological model of loess and the experimental values of remolded loess with different water contents have a better fitting effect,and can better reflect the creep characteristics of remolded loess with different water contents.(4)Under the same water content,the total pore area of remolded loess samples is larger than that after creep.Under the same confining pressure,the number of pores in loess samples increases with the increase of initial water content,and the medium and large pores mostly appear under the condition of high water content.