Influencing Factors And Research Of Impact Factor

With the development of the economy,China’s highway construction has undergone tremendous changes in recent years.The mileage of highway construction has long been the first in the world,and the construction standards have been continuously improved.Nowadays,with the continuous increase in freight volume,heavy trucks have become the main tool for freight transportation,but the growth rate of heavy trucks is always higher than the growth rate of highway mileage,which will cause the impact of heavy trucks on the road surface to become more and more obvious..At present,the static load is used as the design load on the roadbed and pavement.However,as the number of heavy-duty trucks increases,the design load at this time no longer meets the actual requirements.Therefore,some scholars have proposed to multiply the static load by the impact factor as the design load..When a car is driving on the road,it applies dynamic load to the road surface,which causes the force on the ground to be greater than static load and sometimes smaller than static load.The ratio of the maximum peak value of the vibration shaft load to the static load is called the impact factor.The impact factor is generally 1.1-1.4times that of the static load,and is also affected by the speed of the vehicle,the load of the vehicle,and the road grade.This article experiments and discusses these three main factors that affect the impact factor.According to the vehicle model,the relationship between the impact coefficient and the vertical acceleration above the truck beam is first derived,and then the experimental equipment is assembled to perform the experiment.A cluster consisting of three computers is used to process and analyze the data.Finally,the vertical acceleration above the beam is analyzed.a_z data to come to a conclusion.The experimental vehicle in this paper is a four-axle and six-type truck.The data is collected using an integrated device with a high-precision acceleration sensor and GPS module.The experimental equipment is installed above the beam of the rear axle of the truck and is rigidly linked.This article tests a total of 22 road sections in Guangdong Province,including both urban roads in Shenzhen and national roads between cities.At the same time,no-load and full-load experiments are performed.The examples are rich.The experiment was conducted by the control variable method,and the data of the first-grade road Guangshen Highway,the second-grade road G324(Jieyang Section),and the third-grade road Jinbi Road were analyzed.Taking the 85%a_z value of the experimental section as an overall analysis,Jinbi Road has the largest value,reaching 1.21m/s~2,and Guangshen Highway is 1.09m/s~2.The analysis from the three factors shows that the a_z of all road sections will increase with the increase of vehicle speed;the speed performance of different grade roads between different speed sections is different,and the speed range is from 10-20Km/h to the speed range of 41-50Km/h,the increase rate of a_z on Guangshen Highway is only4.4%,and the increase rate of Jinbi Road reaches 7.0%,which indicates that the road grade is the influencing factor of the impact factor;at the same time,the no-load and full-load experiments on the Guangshen Highway show that Under the load condition,the data dispersion is 1.36 times that of the full load,which shows that the load is also a large influencing factor of the impact factor.This experimental study analyzes the influencing factors of the impact factor,lays the foundation for determining the design load in the road design and the axle load conversion in the roadbed and pavement engineering,and provides suggestions for road disease prevention and load limitation.