Study On Falling-weight Deflection And Rebound Deflection Of Subgrade Numerical Correlation And Data Analysis

Subgrade deflection is one of the important detection index in the construction of highway.It also become the parameters must be check in subgrade construction acceptance with the degree of compaction. Not only reflects its own strength, but also the guarantee of the normal work of the road structure. Therefore, subgrade deflection is the key part to decide strength condition, and is the main part of the total deflection of pavement structure. Studies show that more than eighty percent of the pavement deflection shall be borne by the roadbed. Thus, accurate evaluation of subgrade strength is a key link in the highway construction.In this paper, BB test and FWD test was used in the roadbed of high-speed key projects under construction surrounding Hohhot respectively. The relationship between the two sets of data was studied. Starting from the main influencing factors of subgrade deflection, through theoretical analysis and engineering test examples, the degree of compaction, water content, soil particle CBR’s influence on the deflection condition were analyzed; The degree of compaction, water content, soil particle CBR to the influence degree of the subgrade deflection were determined; According to the results of the engineering practice, the influence factors of the subgrade deflection were explained in detail. The BB test results and FWD results of section of highway project were processed, and in accordance with the similar project or closer to the actual conversion relationship were set up; Statistical analysis FWD values is less than the BB values was conducted in the testing results of test section of highway project. The possible causes of FWD values less than the BB values were illustrated. The relationship between subgrade deflection and subgrade material, the influence factors of the correlation coefficient R, the differences deflection value of among different lanes were analyzed; The change rules of testing results was discussed. And the problems during the test were described, and suggestions were put forward. For numerical analysis of FWD, time domain and frequency domain dynamic analysis were adopted. The dynamic characteristics of subgrade were studied. Through the study of thetime domain and frequency domain of numerical description, characteristics of dynamic load and dynamic deflection along with the change of the frequency and the response of the subgrade under dynamic load were studied.