Study On Theory Of Layered Multiphase Elastic Half-Space For The Pavement System

Three-dimensional elasticity analysis of the pavement system under loads is an important respect of soil mechanics and solid mechanics. The paper applies the semi-analytical method to study three-dimensional static and dynamic characteristics of the pavement system under loads. In order to study this problem ,two types of foundation model are considered, including single-phase elastic half-space and two-phase saturated elastic half-space , two types of pavement model are considered, including thin plate model and three-dimensional elastomer model, and three kinds of loads are also studied, i.e.,(i)static loads,(ii)dynamic loads and (iii)moving loads. Based on the semi-analytical method, the paper establishes comprehensive and systematic theory of pavement s static and dynamic characteristics. A unified calculation program has been developed to solve the problem about pavement s static and dynamic characteristics .The followings are studied in this thesis:1. Using traditional thin plate theory and semi-analytic element method, the static and dynamic responses of pavement system based on single-phase elastic half-space foundation model are studied. Semi-analytical functions of pavement plate and single-phase elastic half-space foundation are proposed and basic formulas are established. The effects of foundation parameters and the plate parameters are examined through numerical examples.2. Using three-dimensional elastomer model to simulate rigid pavement plate, then mechanical model of pavement system ,three-dimensional layered elastic half-space, is established. Semi-analytical displacement functions of single-phase elastic half-space foundation and two-phase saturated elastic half-space foundation are proposed. Then the weighted residual method is applied to establish the theory of pavement system s three-dimensional static and dynamic responses. Finally, two examples are calculated with results of three-dimensional responses of infinite plate and limited plate on elastic half-space foundation under loads. It is analyzed the three-dimensional static responses of isotropic concrete plate and orthotropic anisotropy reinforced concrete plate. The distribution regularities of the vertical displacement, lengthways displacement and lateral displacement of pavement surface along horizontal direction are studied and the distribution regularity about foundation's horizontal displacement and vertical displacement along the foundation depth are numerically investigated.3. In the light of single-phase medium theory, the paper derives dynamic control equations and boundary conditions of pavement system based on the single-phase elastic half-space foundation model in the moving coordinates. The Moving Element method for the first time is introduced into the single-phase medium semi-analytical method. Based on s dynamic control equations and boundary conditions in the moving coordinates, the internal residual matrix and the boundary residual matrix of the moving layered element can be derived, and the pavement system based on single-phase elastic half-space foundation model three-dimensional dynamic response semi-analytical equation under moving loads is established applying weighted residual method in order to study the dynamic response of pavement system three-dimensional elasticity under moving loads.Finally, an example is provided to study dynamic response of single-layer elastic half-space foundation under moving loads. The influence law is studied using numerical analysis which includes the impact of many factors (such as velocity, frequency of moving loads, damping of foundation) on the distribution of the foundation s vertical displacement, lengthways displacement and lateral displacement.4. In the light of two-phase saturated soil medium theory, the paper derives dynamic control equations and boundary conditions of pavement system based on the two-phase saturated elastic half-space foundation in the moving coordinates. The Moving Element method for the first time is introduced into the two-phase medium semi-analytical method. Based on s dynamic control equations and boundary conditions in the moving coordinates, the internal residual matrix and the boundary residual matrix of the moving layered element can be derived, and the pavement system based on two-phase saturated elastic half-space foundation model three-dimensional dynamic response semi-analytical equation under moving loads is established applying weighted residual method in order to study the dynamic response of pavement system three-dimensional elasticity under moving loads.Finally, an example is provided to study dynamic response of saturated half-space foundation - elastic foundation - pavement system under moving loads. Using numerical analysis, the influence law is studied which includes the impact of the factors(velocity of moving loads, the depth of elastic soil layer, saturated soil hydraulic conductivity) on the distribution of the pavement s vertical displacement, lengthways displacement and pore pressure in saturated soil.5. Unified pavement system three-dimensional elastic static and dynamic semi-analytical theory is established and calculation program is compiled.The paper applies the semi-analytical method to study three-dimensional static and dynamic characteristics of the pavement system under loads. Two types of foundation model are considered, including single-phase elastic medium and two-phase saturated medium, two types of pavement model are considered, including thin plate model and three-dimensional elastomer model, and three kinds of loads are also studied, i.e.,(i)static loads,(ii)dynamic loads and (iii)moving loads. So issues involve comprehensive.According to analysis and comparisons of three problems this paper studies, the pavement system three-dimensional static response, the three-dimensional dynamic response, dynamic response under moving loads, we can see the dynamic can be transformed into static and movement can be transformed into static, so the three problems are unified; From two types of foundation model this paper study, characteristics research of the pavement system based on single-phase elastic foundation model and the pavement system based on two-phase saturated elastic foundation model, we can see that two-phase medium can be transformed into single-phase medium, so the two types of foundation model are unified; So a unified and comprehensive theory of pavement system is formed, and based on which a unified computer program to systematically analyze and calculate the pavement system is compiled.The paper has solved the current problems existing in the fields of theory and calculation, raised new theory and method for the pavement system, developed and perfected the theory and application system of the pavement. This provides reliable theory and numerical analysis for analysis design, construction safety, failure mechanism research of the related field, such as road, bridge, or traffic engineering.