Dynamic Response Analysis Of Mountain Highway Slope And Subgrade Under Vehicle Loads

As is well known, local trunk road of Chongqing mainly locate in the mountains,which have complex geological structure, and are of geological disaster-prone areas. Inrecent years, the road construction in Chongqing is proceeded in high speed and hasmade leapfrog development. Therefore, the total mileage of local trunk in Chongqingexceeds10,000km.With the increase in road mileage, more and more geologicaldisasters occurr on the road,and in turn, it causes more and more road off road. However,the reasons for geological disasters are complex, including geological conditions, theengineering properties of rock and soil, topography, climate, rainfall, earthquakes,human activities, and amongthese factors, few studies are carried on the impaction ofvehicle load toward the road.In this paper, Chongqing section of the National HighwayG210was set as the research object. With reference to previous researches, dynamicresponse of subgrade under vehicle loads was investigated on the basis of transientdynamic analysis using finite element software ANSYS and simulation of destructionmechanism of soil slope under the road was performed by the Particle Flow Codesoftware PFC3Dbased on DEM theory. The studies do not have to assume the soilconstitutive model and the slip surface. Instead, it micro-defined contact relationshipbetween the particles directly, and the model used force-displacement law and Newton’slaws of motion interchangeably, and constantly update the contact force of the contactportion and reproduce the whole process of the collapse of the soil slope slip byvisualization interface describing the location and geometry of the slope slip surface. Inshort, the dynamic response of the soil slope under the road with the impaction ofvehicle load were studied with the advantage of software ANSYS and PFC3D, thedetailed research was as follows:First, the distribution characteristics and statistical parameters (vehicle load, speedand other parameters) of the Chongqing section of National Highway G210within24hourswere studied through checking of the State Road traffic flow statements andon-site investigation, which would provide a theoretical basis for the establishment ofthe mountain road vehicle load model.Second, based on the roadbed model established by the finite element softwareANSYS to study the dynamic response of the embankment at different depths under thevehicle load, and then further analyze the dynamic response of embankment at different depths with the differentsize of the vehicle load, vehicle speed.Third, with the establishment of discrete element numerical triaxial test model andthe laboratory triaxial test data of the slope soil under the road, the meso parameters ofthe model was obtained by fitting stress-strain curve. At the same time, comparativeanalysis of experimental results obtained by the different model sizes, different particlesize and particle shape numerical model revealed the impact of these factors on themesoscopic particle parameters. What’s more, with the establishment of road slope soilslope model through PFC3D, as well as introduction of the boundary conditions of thevehicle loads, and applying different axle load, vehicle load of different periods anddifferent duration, the destruction mechanism of soil slope under the vehicle load wasstudied, which revealed the impact of soil slope stability and destruction modes undervehicle load.Finally, the main content of this research and research achievements were brieflysummarized, in addition, some suggestions were raised about the research work infurther.