The Research On Experiment Of Resilient Modulus Of Compacted Red Clay In Highway Engineering

The subgrade is the foundation of the pavement structure,as the representative value of subgrade strength index,the resilient modulus is a very important parameter in the design of pavement structure.Subgrade strength not only directly affect the road surface deflection value and the length of the service life of the pavement,but also directly affect design thickness of pavement structure layer.So in the design of pavement structure,can we choose a right resilient modulus is directly related to the safety and economy of pavement structure.Because of the difficulty of the field test,the laboratory testing is an indispensable method to determine the parameters.So how to improve the accuracy and reliability of the laboratory test is the concern of many highway engineers.The research object of this paper is the red clay in Guiyang,theoretical analysis, laboratory test and numerical simulation are used to analysis the resilient modulus of compacted red clay in highway engineering.Research content include the influence factor of the resilient modulus of compacted red clay,effect of size effect on resilient modulus of compacted red clay under unconfined condition,the change laws of the resilient modulus of compacted red clay under drying and wetting cycles and the microstructure of compacted red clay.Finally the following research results are obtained:(1)The relationship between the resilient modulus of compacted red clay and moisture content, compaction degree, consistency and age of the compacted red clay was obtained,it is suggested that the department of highway construction should strengthen the quantitative study of the resilient modulus and its physical index on the basis of actual situation.(2)The ratio of the resilient modulus of the standard sample with side limit and the resilient modulus of standard sample without side limit and the influence ofdifferent diameter and height of samples on resilient modulus without side limit were obtained.(3)The attenuation law of the resilient modulus of compacted red clay under different drying and wetting cycles with different drying and wetting route(first dry then wet and first wet then dry)was obtained(4)The microstructure of compacted red clay with different compaction degree,different moisture content, different drying methods and different numbers of drying and wetting cycles were obtained.Through the research of this paper,acquiring a better understanding of the subgrade resilient modulus,the research results has a certain academic significance and engineering application value on improving the accuracy and reliability of pavement structure design and further evaluation of red clay pavement performance indicators and other aspects.