| Multi-ribbed composite wall structure is a new assembly integral structure system, which adapt our national conditions and meet the wall materials innovation and construction requirements of eco-energy saving, energy saving and shock absorption. Currently, this structure system has been widely used in the unsaturated region that earthquake-prone and high intensity. At present, the system project design is based on the assumption of rigid foundation and the affect of interaction is ignored, the result will be unreasonable and cause a big discrepancy between calculation and reality. In view of this, this paper study the static and dynamic characteristics of the unsaturated loess and establish appropriate constitutive model, then aim at multi-ribbed composite wall structure and research on static and dynamic interaction on unsaturated loess region. The main research contents and achievements are summarized as follows:1, Through remolded soil and undisturbed soil static tri axial tests, analyzed and compared the stress-strain relationship of remolded soil and undisturbed soil under different confining pressure, different water content, analyzed the connection and difference of deformation properties between remolded soil and undisturbed soil under same conditions, thus proposed a reasonable structural parameters and the variation rule. Finally, a static structural constitutive modal considering of undisturbed loess was established.2, Through undisturbed unsaturated loess dynamic triaxial test, analyzed the dynamic characteristics of undisturbed loess under different confining pressure, different water content and different consolidation ratios and get the dynamic stress-strain relationship, the relationship between dynamic modulus and dynamic strain, the mathematical expression of the maximum elastic modulus and damping. Thereby, a dynamic loess constitutive model was established.3, According to the construction characteristic of multi-ribbed composite wall, the equivalent constitutive relationship was established by homogenization method. Based on the interaction mechanism, the multi-ribbed composite wall structure numerical modal considering interaction used the static structural constitutive model was established, and the effect factors were analyzed.4, According to the equivalent principle, the macro-mechanics modal of multi-ribbed composite wall structure was established. The lateral border of soil was simulated by viscous-elastic border considering nonlinear characteristics. The dynamic interaction of multi-ribbed composite wall structure considering interaction used the established dynamic constitutive modal was analyzed by numerical calculation. The change law of some structure parameters including the natural frequency, displacement, acceleration etc. was researched when considering the SSI effect. It maybe gives some useful advice and guidance for engineering practice.5, Aimed at the unsaturated characteristics of loess, based on the single-phase flow consolidation theory and the Bishop effective stress principle, the dynamic foundation impedance of unsaturated loess was obtained. Then the stiffness and damping of the superstructure were obtained. By two-step design method, the MDOF system considering soil - structure interaction was equivalent to a dynamic interaction three-DOF system, and then was equivalent to an equivalent single degree of freedom model that assuming a rigid foundation. Combined with numerical example, the modal was reasonable, can provide a practical calculation of soil - structure interaction system for engineering applications.The originality of this dissertation lies in:1. Combined with unsaturated loess soil static tri axial tests, the static structural constitutive model was second developed based on ANSYS platform, revealed the static characteristics variation law of multi-ribbed composite wall structure considing interaction.Through remolded soil and undisturbed soil static tri axial tests, a static structural constitutive modal considering of undisturbed loess was established. According to the construction characteristic of multi-ribbed composite wall, the equivalent constitutive relationship was established by homogenization method. Based on the interaction mechanism, the multi-ribbed composite wall structure numerical modal considering interaction used the static structural constitutive model was established, and the effect factors were analyzed. 2. Combined with the dynamic interaction theory, the dynamic interaction of multi-ribbed composite wall structure considering interaction was analyzed by numerical calculation; the change law of some structure parameters was researched when considering the SSI effect.Through undisturbed unsaturated loess dynamic triaxial test, a dynamic loess constitutive model was established. According to the equivalent principle, the macro-mechanics modal of multi-ribbed composite wall structure was established. The lateral border of soil was simulated by viscous-elastic border considering nonlinear characteristics. The dynamic interaction of multi-ribbed composite wall structure considering interaction used the established dynamic constitutive modal was analyzed by numerical calculation. The change law of some structure parameters was researched when considering the SSI effect.3. The dynamic foundation impedance of unsaturated loess was derived, a practical calculation of multi-ribbed composite wall structure considering soil - structure interaction at unsaturated loess area was established.Based on the single-phase flow consolidation theory and the Bishop effective stress principle, the dynamic foundation impedance of unsaturated loess was obtained. Then the stiffness and damping of the superstructure were obtained. By two-step design method, a practical calculation of multi-ribbed composite wall structure considering soil - structure interaction at unsaturated loess area was established. Combined with numerical example, the modal was reasonable, can provide a practical calculation of soil - structure interaction system for engineering applications. |
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