دانلود رایگان مقاله انگلیسی اثرات نفوذ بارش و هیسترزیس بر نشست فونداسیون سطحی در خاک اشباع نشده - اشپرینگر 2018

Abstract

The effects of rainfall infiltration and hysteresis on the settlement of shallow foundations in unsaturated soil were numerically investigated. Numerical solutions were verified against experimental data. Rainfall intensities and groundwater table positions, factors that contribute to an additional settlement of shallow foundations, were investigated through a series of parametric studies. The effect of hysteresis on the settlement behavior of shallow foundations was considered by incorporating hysteretic soil–water characteristic curves (SWCC) that were obtained from the laboratory. A Reasonably good agreement of load-settlement response and matric suction distribution was obtained between the numerical analysis results and the field measurements. The parametric study showed that a reduction of matric suction due to rainfall infiltration induced the additional settlement of shallow foundations in unsaturated soil. The groundwater table position appeared to affect the wettinginduced settlement during rainfall due to the changes in matric suction. In addition, wetting SWCC analysis produced a slight larger settlement, up to 5% more than that produced by drying SWCC. Therefore, appropriate SWCCs (i.e., drying or wetting) should be used in numerical analysis in accordance with the conditions of the soils underneath the shallow foundations.

Conclusions

The effects of rainfall infiltration on the settlement of shallow foundations for unsaturated soil were numerically investigated using the finite element analysis commercial software PLAXIS 2D. The effect of hysteresis on the settlement behavior of shallow foundations was considered by incorporating hysteretic soil–water characteristic curves (SWCCs) obtained from the laboratory. The nonlinear relationship between the modulus of elasticity and matric suction was considered in the sequential analysis. The numerical solutions were validated against the experimental data. In addition, parametric studies were carried out to explore the factors affecting additional settlement of shallow foundations. The following conclusions can be drawn:

1. The analysis that incorporated matric suction found reasonably good agreement for load-settlement response between the numerical analysis and the field load test results. Moreover, the distribution of matric suction with different depths was well predicted by the developed 2D FE model.

2. The initial matric suction in unsaturated soil exhibited obvious reinforcing effects for the stability of shallow foundations as settlement decreased because of the high modulus of elasticity as the matric suction increases.