Apply the theories of elasticity, viscoelasticity and mechanics of materials to calculate the stress and strain in the multilayer pavement system, and verify the resistance of the pavement structure.
??Establishing a mathematical-mechanical model for the pavement system is a way to solve practical engineering problems using scientific principles.
Researchers always try to adopt certain assumptions, or ignore certain factors, so that the mathematical-mechanical model of the pavement system can be simplified in order to obtain theoretical solutions, and then through experimental means modify the theoretical results to make them practical.
At the end of the 19th century, some theories of elastic mechanics suitable for pavement design were developed, such as the liquid-bearing plate proposed by HR Hertz in 1884, and the subject of semi-spatial elasticity proposed by JJ.-V. Bussenesk in 1885 Pavement design research from the first half of the 20th century has been used.
Based on Hertz’s theory, HMS Westgard published a paper on stress analysis of cement concrete pavement in 1925, and it is still used in rigid pavement design practice. In 1938, AHA Hogg made the solution of infinitely many thin plates on elastic bases. And in 1945, DM Burmister’s theoretical solution for the calculation of stress and displacement of double-layer and multilayer elastic systems has a great influence on the development of the design theory of rigid pavements and flexible pavements.
In recent years, due to the application of fast large-scale electronic computers, as well as the development of elastic mechanics and numerical calculations, it has become possible to compile electronic computer programs for any elastic multilayer system to calculate the sum of stresses in any system point under vertical and horizontal loads. Displacement, such as the ELSYM program of the California Research Institute (State) and the CHEV-5L program of the Chevron Research Company, the BISAR program of the Dutch Shell Research Group, and the GCP-1 Program of the Australian Federal Institute of Science and Industry.
In addition to the development of mechanical calculations for multilayer elastic systems, the VESYSIIM software for layered viscoelastic systems has also been compiled; New developments have also been made in the use of finite element technology to process laminated systems and finite-size plates on elastics. foundations. The results of the previous research have been partially applied to pavement design.
In the calculation of the pavement mechanics, in addition to the analysis of the stress and displacement of the stratified system and the plate on the stratified system, the determination of the resistance index of the pavement material (tensile, shear or resistance) must also be carried out. deformation). included, and According to the mechanical characteristics of the pavement system damage, the strength verification theory of the pavement structure is established. For this, the theory of the resistance of objects in a state of complex stress (three-dimensional stress) in the mechanics of materials must be used.