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The consolidation of unsaturated soil is of great significance to road engineering, soft foundation soil improvement, etc. Based on the one-dimensional consolidation theory of unsaturated soil proposed by Fredlund and Hasan, the governing equations for pore water pressure and pore air pressure in the soil are established. The initial conditions and a type of time-dependent mixed nonhomogeneous boundary conditions of single-layer unsaturated soil are presented which constitutes the solution of 1D consolidation of unsaturated soil. The homogenization of nonhomogeneous boundary conditions and the eigenfunction expansion method are adopted to derive exact analytical solutions in time domain for the dissipation of pore water pressure and pore air pressure in the soil. Finally, the method proposed in this paper is validated by comparison with published results, and several examples are used to analyze the effects of exponentially changing boundary conditions on the dissipation of pore water pressure, pore air pressure, and deformation of unsaturated soils. The results show that the speed of exponential change of pore pressure on the boundary or flux across the boundary has significant effect on the consolidation process of unsaturated soil.

Many offshore marine structures are built on the seabed that are slightly or considerably sloping. To study the sloping seabed transient response during marine earthquakes, an analytical solution induced by a P-wave line source embedded in the solid is presented. During the derivation, the wave fields in the fluid layer and the semi-infinite solid are firstly constructed by using the generalized ray method and the fluid‒solid interface reflection and transmission coefficients. Then, the analytical solution in the transformed domain is obtained by superposing these wave fields, and the analytical solution in the time domain by applying the analytical inverse Laplace transform method. The the head wave generation conditions and arrival times at the fluid‒solid interface are derived through this solution. Through the use of numerical examples, the analytical solution is proved right and the impacts of the sloping angle on the hydrodynamic pressure in the sea, the seismic wave propagation in the seabed, the head wave, and the Scholte wave at the seawater-seabed interface are also addressed. [ABSTRACT FROM AUTHOR]

Chengde's transitional region from plateau to plain is located in the transition zone of agriculture and livestock and is extremely sensitive to climate change and human activities. This study used the net primary productivity(NPP) of vegetation as an evaluation index to quantify the degree impacts of climate change and human activities on vegetation change in the region. The Thornthwaite Memorial model was used to calculate the potential NPP, and the actual NPP was obtained based on MODIS NPP remote sensing images, using the difference between the actual and potential NPPs to express the amount of change in NPP owing to human activities. We used the slope trend and coefficient of variation method to analyze the trend and stability distribution of the actual NPP, potential NPP, and NPP influenced by human activities, and the correlation between actual NPP and annual precipitation and annual average temperature was analyzed using the correlation coefficient method. Finally, we quantified the impact of climate change and human activities on vegetation change in the region. The results showed that 99.87% of the vegetation in the region was improved and changed steadily, and the proportions of the areas showing positive correlation between actual NPP and annual precipitation and annual average temperature were 99.87% and 91.66%, respectively. The potential NPP showed an increasing trend from northwest to southeast, whereas the trend and stability of the potential NPP both showed an increasing trend from west to east. The area where climate change and human activities played a role in vegetation improvement accounted for 99.71%, and that affected by climate change accounted for 0.14%, with the proportion of human activities leading to vegetation degradation being 0.15%.