Study On The Traceability And Transfer Technology Of International Roughness Index

International Roughness Index (IRI) is an general international technique index which is widely used to evaluate road pavement smoothness. Road roughness plays an important role in quality supervision of engineering project, service level evaluation of operating road and pavement maintenance design. Now there are many users of pavement roughness testing equipment in China. However, because of the difficulties in the traceability and inspection of these test facility, measurement accuracy has been acutely questioned.Research course was carried out through the technology route that takes theoretical analysis first and practice test following. Firstly, a more comprehensive questionnaire survey of equipment manufacturers is made in homeland and foreign countries as well as the typical users of domestic. The producing and using status of roughness testing equipment is acquired. In order to ensure the accuracy of roughness testing equipment, some research work on how to calibrate equipment is made, but the technique is relatively rough. However, the achievements in program design and test methods provided practical experience for establishing measurement standards. From the original point of view, systematic analysis of the theory model of IRI is carried out and the features and advantages of the standardized reference quarter car are summaried. Using experimental method of theoretical simulation, three different solutions for the start value which affects the calculating results are proposed. It proves that lengthening statistics interval or"cut off"start interval analysis method can reduce the error,which is introduced by different data processing method. By means of roughness profile analysis and statistic analysis, reasonable statistical step for IRI calculation has been stuied. Considering the frequency response features of international roughness index model, we came to the conclusion that the statistical step for IRI should be no less than 30 meters. This provides the basis for calculating statistics step of measurement standard.Secondly, with the combination thinking of classic dynamic model and quarter car model, starting from the source of stimulate system, traceable index of IRI system is been explored. Then the two main types of pavement roughness testing equipment, laser profilometer and bump response integrator, are systematically analyzed. It also draws the hierarchy scheme of IRI and the scheme provides technical requirements of measurement standards at all levels. Three kinds of implementation scheme of measurement standard have been proposed. The technology of changing pavement roughness levels by using rapid elevation transform has been developed, which helps us to achieve the goal to establish measurement standards in the same platform and get through the process of traceability. It can effectively control the stability of measurement standards. Some auxiliary equipments in realizing rapid elevation transform, such as standard module, were developed. The work of development and evaluation of level one measurement standard is done and the standard has no more than 1% relative uncertainty. Based on traditional laser profilometer, through improving the hardware performance and introducing the time frequency sampling technique, data sampling and processing reduces sampling restore error in usual program. The accuracy of entire system is improved. All technical specifications meet level two measurement standard requirement, whose relative uncertainty can be controlled below 3%.Finally, the most representative roughness measurement equipments are used to do experiments on the two measurement standards. The test results fully validate the effectiveness of the measurement standards, which can provide legal and effective way for the traceability of pavement roughness measurement equipments.