Experimental Study On Dynamic Characteristics Of Rubber Particle Modified Expansive Soil

With the rapid development of China's economy,the speed of material replacement is faster than before.Among them,the automobile industry as the representative,the number of waste parts is increasing year by year,and among these,the tire is more serious.The disposal of used tyres has so far been a challenge for countries.Difficult to degrade,burning pollution problems and so on resulting in waste rubber is called difficult to deal with black garbage.On the other hand,expansive soil as special soil,problem soil,because of its expansibility and other physical and mechanical indicators usually can not meet the basic requirements of highway subgrade,but in practical construction,it is often treated with abandoned side or admixture such as gravel,lime,cement and so on.Therefore,it is considered to add the waste rubber particles after mechanical crushing to the expansive soil to form the modified expansive soil,to study its dynamic characteristics,to obtain dynamic parameters such as dynamic stress,and to apply it to practical engineering,so as to provide a reference and outlet for the design of architectural engineering.According to some experimental studies by domestic scholars,it is found that the main components of expansive soil are montmorillonite,kaolinite and illite^[1].Therefore,the research object of this experiment is to mix kaolin and bentonite in a certain proportion and then add rubber particles and cement,and analyze the influence of waste tire rubber particles and cement on the basic physical and mechanical properties and dynamic characteristics of expansive soil by means of theoretical analysis and indoor static and dynamic test,etc.On this basis,the main conclusions are as follows:?1?Through the boundary compaction test of modified expansive soil,it is found that the physical properties of expansive soil changed after adding rubber particles,the plastic limit increased,the liquid limit remained basically unchanged,and the plastic index of soil decreased.With the increase of rubber content,the density of modified expansive soil decreases,and the unconfined compressive strength increases first and then decreases.?2?Through the dynamic triaxial test of expansive soil with different rubber content,the dynamic stress-strain curve of modified expansive soil decreases obviously with the increase of rubber particle content,and the linear characteristic of dynamic shear modulus-dynamic shear strain curve increases obviously,indicating that the damping ratio of energy loss will also increase.And with the increase of dynamic strain,the dynamic stress-strain curve shows an increasing trend.The model of dynamic stress-strain curve and dynamic shear modulus accords with the hardin-dmevich model,and the damping ratio accords with the modified Chen Guoxing model description.?3?The results of dynamic triaxial test of modified expansive soil with different cement content show that the dynamic shear modulus and damping ratio of modified expansive soil increase with the increase of cement mixing ratio.?4?The dynamic triaxial test of the modified expansive soil under different confining pressures results in the increase of the confining pressure,the increase of dynamic shear modulus,the decrease of damping ratio damping ratio decreasing and the dynamic stress-strain curve.