Laboratory Test Of Dynamic Characteristics And Numerical Simulation Of The Subgrade Of The Yellow River Extension Highway Under Driving Load

With increasing traffic,in order to meet the needs of regional economic development,many expressways in the Huangfan District have undertaken expansion projects.However,the expansion of the expressway is a tedious project,the new and old roadbeds during the operation period will undergo large differential settlements under driving loads.If it is not controlled,it will cause longitudinal cracks on the highway pavement and seriously affect driving safety.Therefore,this article relies on the expansion project of the Zibo West to Laiwu section of the Binlai Expressway,indoor geotechnical tests were carried out to study the engineering characteristics of highway subgrade soil in the Huangfan District;Dynamic triaxial tests of new and old subgrade soils were designed to study the evolution law of dynamic response evolution of subgrade soil under the action of driving load;According to the Binlai high-speed expansion project,a three-dimensional numerical calculation model of new and old roadbeds was established to study the deformation characteristics of the new and old roadbeds under the action of traffic loads.The main work and conclusions of this article are as follows:(1)Based on particle analysis test,limit water content test,compaction test and triaxial compression test,the physical indicators such as the soil quality and strength index of the roadbed filling in the Huangfan area were determined,the variation laws of stress-strain,pore pressure ratio-strain and stress path of subgrade soil are obtained(2)Analyzed the driving load characteristics of the expressway in the Huangfan District,quantified its frequency and axle load.Carried out a three-axis test of the dynamic characteristics,the time-history evolution law,spatial distribution law and driving load amplitude influence law of roadbed soil dynamic response are studied,the dynamic modulus attenuation curve and the Ed-εd fitting formula are obtained.Based on the dynamic triaxial test,through the measurement test of elastic modulus,shear modulus,internal friction angle and cohesive force,the differences in mechanical properties of the new and old subgrades were studied(3)Combined with the indoor triaxial test,the accuracy of the numerical model and calculation method was verified.Established the numerical calculation model of the new and old subgrades at the actual engineering scale,and added to the law of dynamic modulus attenuation obtained by experiment,the differential deformation law of the new and old roadbed under the action of traffic load is studied.