To comprehensively investigate the integrated structural and material design of the epoxy asphalt mixture used in steel bridge deck pavement, the following works have been conducted: 1. The strain level of steel bridge deck pavement was calculated; 2. The ultimate strain level of fatigue endurance for epoxy asphalt concrete was measured; 3. The effect of water tightness of epoxy asphalt mixture on the bonding performance of steel plate interface was tested. 4. For better performance evaluation, quantitative analysis of the anti-skid performance of epoxy asphalt mixture was carried out by testing the structure depth using a laser texture tester. Results show the following findings: 1. The fatigue endurance limit strain level of epoxy asphalt mixture (600 με) was higher than that of the steel bridge deck pavement (<300 με), indicating that the use of epoxy asphalt concrete has better flexibility and can achieve a longer service life in theory; 2. The epoxy asphalt concrete has significant water tightness to protect the steel plate interface from corrosion and ensure good bonding performance; 3. The porosity of epoxy asphalt mixture used in steel bridge deck paving should be controlled within 3%; 4. In terms of anti-skid performance of bridge deck pavement, the FAC-10 graded epoxy asphalt mixture is recommended when compared with EA-10C.

The deformation and strength characteristics of saturated clay are studied through a cyclic triaxial test of clay in the Wenchuan earthquake area. Specifically, the effects of cyclic stress ratio, initial shear stress, and vibration frequency on the dynamic characteristics of saturated clay are analysed. Results show a failure strain in the dynamic strain development of saturated clay. Before the failure strain, the dynamic strain of soil develops slowly. After the failure strain, the soil strain increases sharply and leads to failure. Under the same confining pressure, the failure strain produced by different cyclic stress ratios has a linear relationship with the failure frequency. The dynamic strain development curve of saturated clay can be simplified to failure, transition, and stability types, which are mainly affected by the cyclic stress ratio. Initial shear stress and vibration frequency have significant effects on the deformation and strength characteristics of saturated clay. The larger the initial shear stress or the lower the vibration frequency is, the more sufficient the dynamic strain of soil develops and the fewer the number of cycles required to reach the same dynamic strain. Under the same number of cycles, the larger the initial shear stress or the lower the vibration frequency, the smaller the dynamic stress required to cause soil failure and the lower the dynamic strength of the soil. A turning point exists in the dynamic strength curve of clay. The smaller the initial shear stress or the higher the vibration frequency, the smoother the curve after the turning point and the smaller the tangent slope.

No abstract

Initial shear stress is inevitable in actual engineering slopes, subgrades and foundations. The soils exhibit different dynamic characteristics under an initial shear stress. The dynamic strength characteristics of saturated clay under cyclic loading were studied through a dynamic triaxial test of remoulded clay in the Wenchuan area. The effects of the failure criterion, initial shear stress and vibration frequency on the dynamic strength characteristics of saturated clay were also analysed. The results showed that the strain failure criterion with a strain value of 2.5 % or the transitional strain εtp can reflect the soil damage realistically and evaluate the dynamic strength of the soil objectively. εp = 2.5 % can be used to replace εp = εtp when the dynamic strength parameter of the saturated clay was calculated under seismic loading equivalent failure vibration times. The dynamic strength parameters of the saturated clay under different earthquake magnitudes were calculated by introducing the equivalent failure vibration times of the soil under seismic loading, thereby providing data support for the stability analysis of the clay foundation under seismic loading. The initial shear stress and vibration frequency have a considerable effect on the dynamic strength of saturated clay. Under the same vibration frequency, the larger the initial shear stress is, the smaller the required dynamic stress is for the soil to break, and the smaller the dynamic strength parameter is. The existence of the initial shear stress reduces the dynamic strength of the soil. Under the same vibration times, the higher the vibration frequency is, the greater the required dynamic stress is for the soil to break, the larger the dynamic strength parameter is, and the greater the dynamic strength of the soil is.