Study On Dynamic Deformation Characteristics Of EPS Particles Light Weight Soil Under Dynamic Loading

Expandable polystyrene foam particles light weight soil,also known as EPS particles light weight soil,light weight soil has a series of advantages,such as small density,high strength,good plasticity,good self-reliance,good vibration isolation and heat insulation,etc.In this paper,we take loess as the raw material soil,the light material adopts EPS particles,and the curing agent uses cement to prepare EPS particles light weight soil.Through the density test,unconfined compression test and the indoor dynamic triaxial test to study the density of the EPS particles light weight soil,as well as unconfined compressive strength and dynamic deformation characteristics,the main contents include:（1）Through density test and unconfined compression test,the static characteristics of EPS particles light weight soil were studied,and the effects of cement incorporation ratio,EPS particle incorporation ratio,curing period and water content on the density,strength and deformation characteristics of the mixed lightweight soil were studied.The test results show that:In this experiment,the range of unconfined compressive strength of the light weight soil was 103.2kPa¹359.0kPa,and the strength increase with an increasing trend of exponential relationship with the cement content,but showed the linear relationship decreased with the increase of the volume ratio of EPS.When the water content in the test is greater than the optimum moisture content,the more water,the lower the unconfined compressive strength,there is a index tendency both of them,but the growth of the curing period make the unconfined compressive strength of light weight soil increase with the hyperbola tendency.Stress-strain relationship curves of EPS particles light weight soil is the type of strain softening,the increase of moisture content and EPS particles volume makes the light weight soil stress strain relationship curves gradually to sclerosis type.The increase of cement content and curing period can enhance the brittleness characteristic and increase stiffness characteristic of light weight soil.However,the increase of water content or EPS particles ratio,increases the ductility characteristics of EPS particles light weight soil and decreases the stiffness characteristic.The research results are of reference value to practical engineering applications.（2）The dynamic deformation characteristics of EPS particles light weight soil were studied by means of indoor dynamic triaxial test.The skeleton curves of EPS granule mixed lightweight soil has obvious hyperbolic characteristics,while the^relationship curve of EPS granule mixed lightweight soil has the characteristics of negative power function attenuation.The increase of Consolidation confining pressure and cement admixture is able to make the light weight soil has a higher dynamic strength,and could obviously enhance the light weight soil earlier and middle initial compression modulus and deformation resistance,but the higher dosage of EPS particles have the opposite effect.The vibration frequency only affected the skeleton curves of the medium（0.3%<?_d≤2%）,which could not increase the ultimate dynamic strength of the light weight soil,and could only increased the ability of the sample to resist deformation in the middle of the vibration（0.3%<?_d≤2%）.Due to the complex composition of lightweight soil and the complex stress state,the influence laws of each factor on the damping ratio is not clear enoughTo simulate the limit state condition of vacuum operation of the structural damage is bigger,not for vacuum operation,EPS particles content for 1.31%of the sample is still has a good dynamic deformation characteristics,but when the content was 2.01%,due to the excessive amount of EPS particles,the dynamic deformation behavior is poor,and it is recommended to be used cautiously in the engineering.（3）The dynamic stress-strain relationship curves of EPS particles light weight soil has obvious hyperbolic characteristics.The more consolidation confining pressure and cement content,the lighter soil dynamic carrying capacity of the stronger,but EPS particles content is the opposite.In the middle of the vibrational process（0.3%<?_d≤2%）,the faster vibration frequency can make the light weight soil have higher dynamic stress,but it does not improve the dynamic strength of the lightweight soil,and the corresponding dynamic stress difference of the failure strain is less than 5kPa.By analyzing the Hardin-Drnevich model,the initial compression modulus₀Eand the maximum axial dynamic stress?_y of the model parameters is obtained.The more increase of cement content and consolidation confining pressure,both₀E and?_y increases,the higher the dynamic strength,the better the resistance to dynamic deformation,while the influence of EPS particles content on model parameters is the opposite.The vibration frequency has little influence on the model parameters₀E,so it can only improve the intermediate dynamic strength and the ability to resist dynamic deformation of the light weight soil.By changing the stress strain state to verify the test,the backbone curves of the verification test was obtained.Then the dynamic constitutive parameters are calculated by interpolation method,compare measured points and calculated values.The difference between them is less than 10kPa,this indicates that the Hardin-Drnevich model can be used to describe the skeleton curves of light weight soil.