Effect Of Gravel Shape And Gravel Content On Dynamic Characteristics Of Gravel-mixed Sand Soil

The gravel soil used as a basic material plays an increasingly important role in the project with the gradual development of China's high-speed railway,subway tunnel,artificial reclamation,offshore immersed tunnel and other projects.Higher requirements are put forward for the safety and stability of these important engineering projects in order to meet the increasing material requirement of people.For gravel soils as basic materials,scholars have achieved substantial achievements on their dynamic characteristics,mainly focusing on the influence of vibration frequency,void ratio,consolidation ratio and consolidation pressure on the dynamic characteristics of gravel soils,while relatively few scholars study the influence of gravel particle characteristics,size and shape.Under the background,the effects of gravel shape,gravel content and consolidation pressure on the dynamic characteristics of saturated gravel-mixed sandy soil are studied in this paper based on the research of dynamic elastic modulus test and dynamic strength test,so that reveal the influence of gravel shape,gravel content and consolidation pressure on the dynamic modulus of elasticity,damping ratio,maximum dynamic modulus of elasticity,dynamic strength and dynamic pore pressure.Through experimental research and analysis,the following conclusions are concluded:1)In the experimental study of dynamic modulus of elasticity and damping ratio,the dynamic constitutive relationship of gravel-mixed soil can be expressed with Hardin-Dmevich viscoelastic model,with adaptability,the curve shows a good linear relationship when the backbone curve is transformed into the d/d d curve.2)Consolidation pressure has the greatest influence on the dynamic modulus of elasticity of gravel-mixed sandy soil.Along with the increase of consolidation pressure,the increase of the maximum dynamic elastic modulus of gravel-mixed sandy soil is the biggest.The influence of gravel content is the second,and the dynamic modulus of elasticity increases along with the increase of amount gravel content.The dynamic elastic modulus of sub-circular gravel-mixed sandy soil is the smallest when the consolidation pressure is low,while the schistose gravel is the largest.The schistose gravel will break up and the dynamic elastic modulus will decrease to a certain extent along with the consolidation pressure increase.3)The shape of gravel,the amount of gravel and the consolidation pressure influence the development of damping ratio.With the increase of consolidation pressure,the maximum damping ratio has the downward trend;with the increase of gravel content,the maximum damping ratio decreases;with more irregular shape of gravel,the maximum damping ratio increases.4)In dynamic strength test,this paper focuses on the development of dynamic pore pressure and dynamic strength curve.Among them,gravel content has the greatest influence on dynamic strength.Along with the increase of gravel content,the required dynamic stress ratio of saturated gravel soil is bigger under the same vibration failure times and the the dynamic strength is higher.The shape of gravel has some influence on the dynamic strength.The dynamic strength of sub-circular gravel-mixed sandy soil is the lowest,followed by angular gravel-mixed sandy soil and schistose gravel-mixed sandy soil is biggest.As for the development of pore pressure,the shape and amount of gravel have a great influence.The more gravel is added,the larger the pore pressure ratio is under the condition of the same destructive vibration ratio,while the consolidation pressure has no great influence on it.