Study On Structural And Dynamic Characteristics Of Typical Loess In The Middle Section Of Chenglan Traffic Corridor

Loess is a kind of typical structural soil that is widely distributing in the world.The area of loess in China is about 640,000 km~2,accounting for 6.3%of the country's land area.Due to its special structure,special sensitivity to water and earthquakes,loess mass possesses special engineering mechanical properties,therefore,studying the mechanical properties,especially the dynamic properties of typical loess mass has important theoretical significances and engineering values.On the basis of summarizing and analyzing the previous studies on the dynamic characteristics and structural characteristics of loess,this paper calculates and analyzes the typical loess in the middle section of Chenglan Traffic Corridor based on the GDS dynamic triaxial test(Jiaochang loess and Songpan loess).Dynamic constitutive relation,dynamic elastic modulus,dynamic strength characteristics,dynamic damping ratio characteristics,structural strength and structural parameters of loess,combined with static compression test and static and wet test,comprehensive analysis of vibration subsidence coefficient and collapsibility coefficient the relationship between.With the development of axial deformation,the dynamic stress inside the specimen increases,the rate of increase gradually decreases,and the curve tends to be gentle.The dynamic stress-dynamic strain of undisturbed loess and remolded loess is hyperbolic;the dynamic elastic modulus gradually The rate of decrease decreases gradually,the curve tends to be flat,and the dynamic damping ratio gradually converges.The dynamic elastic modulus,dynamic strength,cohesive force and friction angle all decrease with the increase of water content.The structural strength decreases with the increase of water content and increases with the increase of confining pressure.The strength difference of the joint structure increases with the increase of water content and increases with the increase of confining pressure.Before the friction structure is destroyed,The friction structure strength decreases with the increase of confining pressure;after the friction structure is destroyed,the strength of the friction structure increases with the increase of confining pressure;the school field loess and Songpan loess show differences in the failure point of the friction structure strength:the friction structure damage of the school loess The point decreases with the increase of water content,and the friction structure of Songpan loess increases with the increase of water content.The coefficient of refraction corresponding to the same dynamic stress increases with the increase of water content,and decreases with the increase of pressure.The coefficient of refraction of the original sample is smaller than that of the remolded sample.Combined with static compression test and static collapsibility test data analysis,the practical significance of establishing static collapsibility coefficient and dynamic refraction coefficient is not great.More research should be focused on loess structural parameters.The above research in this paper shows that when studying the dynamic characteristics and structure of loess,the changes of basic physical properties such as water content and dry density play an important role in the dynamic characteristics and structure of loess.However,for the loess in different regions,in addition to considering the effect of dry density and water content,it is also necessary to consider the effects of different structuralities of loess.In the analysis of the field loess and Songpan loess,the structure plays an important role in the static and dynamic characteristics of the two typical loess.It affects the dynamic characteristics in a larger range,and should be explored more qualitatively and quantitatively.And the law of parameter changes.