Phd in INFRASTRUCTURES AND TRANSPORT

Thesis title: Experimental and Numerical Investigation of Non-Stationary Temperature Field in Road Structure

The dissertation presents the results for the analysis of experimental studies of the temperature regime in the road structure in various regions of the Republic of Kazakhstan. An algorithm has been developed for solving the problem of non-stationary thermal conductivity by the finite element method for a multilayer road structure in a two-dimensional setting. A mathematical model has been developed that allows one to describe the stress-strain state of a multilayer road structure using the finite element method with an 8 nodal rectangular quadratic finite element and calculations have been performed to determine it. The influence of the climatic features of the regions on the stress-strain state of the pavement and the subgrade has been investigated. The origin of a single vertical fatigue crack and its effect on the formation of the stress-strain state of a multilayer road structure is considered. Numerical methods are currently the main tool for solving complex mathematical models and problems. They reduce the solution of a problem to performing a finite number of arithmetic operations on numbers and give the result in the form of a numerical value with an error acceptable for the given problem. A two-dimensional formulation of the problem is necessary when considering the problems of thermal conductivity in urban roads, where, as a rule, various engineering structures are located under the carriageway, in particular, heating lines. A similar formulation will be required even when solving problems of thermoelasticity. The ultimate goal of this research is to create a computational algorithm for determining the non-stationary temperature field at the points of road structures located in different climatic zones of the Republic of Kazakhstan. On the basis of the algorithm for solving the problem of non-stationary heat conductivity in road structures, a computational program was developed in MATLAB and the hourly change in the temperature field at points of the road structure on road sections located in various regions of the Republic was investigated.