Analysis On The Bottom Strain Of The Layered Structure Based On The Model Test

Pavement is a typical lamellar structure. The thickness and intensity of each layer canaffect the pavement performance and lifespan. The tensile strain of the bottom of the roadsurface is one of the control indexes in long-life pavement design. Many countries aretrying to use bottom tensile strain as road design control index. Therefore, the research onthe influence factors of the bottom tensile strain has important practical significance. It canprovide reference for structure design especially road design.The road prototype test on the scene has many problems, such as time-consuming andcostly, more interface factors, the test of the construction work that has not yet been built isunable to carry out, the test results are not conducive to promote and so on. Therefore, in thispaper, model test method was used to analysis the impact of thickness, modulus and contactstate between each layer on the bottom tensile strain. Resistance strain gage and datacollection instrument DT85G were used in the experiment. The ANSYS finite elementmethod was used to numerical simulation calculate tensile strain of the layer bottom at themeantime. Then the simulation results were compared with the experimental results.The main conclusions are: the axial strain is greater than the lateral strain；In order toreduce the bottom strain, simply by increasing the surface modulus was difficult to achieveexpected effect, increasing the surface thickness on the basis of appropriate surface moduluscan obtain good effect；The tensile strain of layer bottom under continuous contact conditionwas smaller than the strain that under smooth contact condition；The influence of dynamicload on the bottom strain was bigger than static load when the interlayer contact state isdifferent；Improving interlayer contact condition can significantly decrease the bottom tensilestrain. ANSYS finite element calculation results were consistent with experimental results；With the help of the ANSYS finite element method, the influence law of the factors on bottomstrain can be further determined.