Study On Strength And Deformation Behavior Of Silty Soil In The Yellow River Flood Area Subjected To Stress Principal Axis Variation

Silty soil is widely distributed all over the country,because of the location and cause of the difference,the thickness of the sediment particles are very different,resulting in different soil.The Yellow River has frequently flooded and altered its path.In the vicinity of the primary current of the river,there is a swift flow rate,and the sediment consists predominantly of sand and silt.After the yellow water retreated,there was drought and water shortage,and the wind erosion was strong,forming a large area of silty soil layer and poor engineering properties.In the engineering design,construction and operation in the yellow plain area,the soil load has the static characteristics of directional shear and pure rotation of the principal stress axis,which has obvious influence on the soil anisotropy.Anisotropy is a term used to describe how the physical and mechanical properties of materials vary in different directions,and it is a critical factor that affects the mechanical properties of silty soil.Consequently,when dealing with this type of silty soil in complex stress states,it becomes necessary to consider its strength and deformation characteristics.To this end,it is imperative to investigate the impact of anisotropy on the physical properties of silty soil,building upon the existing strength theory of this soil type.According to the actual drainage condition,this paper carries out directional shear and stress spindle pure rotation tests under silt drainage condition.The strength,deformation and anisotropy characteristics of soil are obtained,which can provide theoretical basis for engineering construction in this area.The primary focus of this paper comprises of the following components:(1)In the directional drainage shear test of isotropic consolidation,large principal stress direction Angle a and medium principal stress coefficient b are considered.The development trend of each strain component,octahedral stress-strain relationship,shear stress-strain relationship,shear stress ratio,non-coaxial characteristics and failure envelope are analyzed systematically from the anisotropic perspective.The strength and deformation of yellowbrown loess are significantly affected by both of a and b,and the degree of influence of the anisotropic characteristics under different stress paths varies.(2)In post-directional drainage shear shear tests with different initial consolidation Angleζ.The effects of initial consolidation Angle ζ and middle principal stress coefficient b were considered.The development trend of each strain component,the relation between octahedral stress-strain,radial strain,circumferential strain and shear stress,and the non-coaxial characteristic system are analyzed from the anisotropic Angle.When b=1,the stress-strain relationship and non-coaxial behavior of the loess are most significantly influenced by the initial consolidation angle ζ.(3)In principal stress rotary drainage test,the development trend of strain component,shear stress-strain relationship and the development law of volume change of silty soil were analyzed systematically from the anisotropic Angle by considering different principal stress coefficient,initial consolidation Angle ζ and number of circulating cycles.It can be observed that the initial consolidation angle has a more significant effect on the stress-strain relationship of the principal stress rotation test than the ratio of the initial consolidation angle to the principal stress coefficient,and the hysteresis loop of shear stress-strain shows apparent cyclic creep characteristics.The research methods and ideas employed in this article have certain reference value for experiments and simulations on other types of silty soil.