Interface Effect And Long-Term Stability Analysis Of Double Subgrade Soil Layer

The rapid development of national economy led to the development of transportation in our country,the highway to vigorously develop the regional distribution of a lot of hard soft-type double-layer subgrade,this kind of foundation is becoming a hot spot of attention.Under the action of traffic load,a dynamic mutagenesis occurs at the interface,which is called interfacial effect.The mechanism of interface effect has become a hot topic in research.At first,this paper study on the properties of soft roadbed interface characteristics,determine the type of contact area,at the interface between hard and soft soil using flac3 d to establish contact and simulation in the interaction of hard and soft soil under traffic loads.The parameters of interface are selected and the influence of interface parameters on the dynamic stress near the interface is investigated.This paper analyzes the necessity and rationality of establishing interface model based on interface depth.Secondly using the numerical model is established to explore the mechanism of the effect of contact interface,revealing the interface effect namely the causes of the interface stress mutation is the hard and soft soil grain body occurs at the interfaces embedded into each other,contact with embedded displacement.The effects of the thickness of the axle,the thickness of the hard shell,the density of the hard shell,the thickness of the hard soft soil layer on the interface layer and the embedding displacement of the contact surface are analyzed.Finally,the performance of subgrade under long-term loading is studied.Under the long-term load,the strength and stiffness of hard soft soil and interfacial layer are attenuated and the dynamic stress level of the hard soft soil layer is analyzed,including the thickness of the hard shell,the axle weight,the modulus ratio of the hard and soft soil layer and the speed.The sensitivity of these four factors to the stability of the double-layer subgrade is determined by the change of dynamic stress level,which is: the thickness of the hard shell,the axle weight,the modulus ratio of the hard and soft soil and the speed of the vehicle.