Three dimensional numerical simulation of residential building on shrink–swell soils in response to climatic conditions

Abstract

SUMMARYShrink-swell soils can cause distresses in buildings, and every year, the economic loss associated with this problem is huge. This paper presents a comprehensive system for simulating the soil-foundation-building system and its response to daily weather conditions. Weather data include rainfall, solar radiation, air temperature, relative humidity, and wind speed, all of which are readily available from a local weather station or the Internet. These data are used to determine simulation flux boundary conditions. Different methods are proposed to simulate different boundary conditions: bare soil, trees, and vegetation. A coupled hydromechanical stress analysis is used to simulate the volume change of shrink-swell soils due to both mechanical stress and water content variations. Coupled hydro-mechanical stress-jointed elements are used to simulate the interaction between the soil and the slab, and general shell elements are used to simulate structural behavior. All the models are combined into one finite element program to predict the entire system's behavior. This paper first described the theory for the simulations. A site in Arlington, Texas, is then selected to demonstrate the application of the proposed system. Simulation results are shown, and a comparison between measured and predicted movements for four footings in Arlington, Texas, over a 2-year period is presented. Finally, a threedimensional simulation is made for a virtual residential building on shrink-swell soils to identify the influence of various factors.

Simulating the behaviour of reactive soils and slab foundations using hydro-mechanical finite element modelling incorporating soil suction and moisture changes

“…Moreover, the soil properties in the stress phase is most often assumed to be constant; however, unsaturated soil properties are highly dependent on the moisture variation and the ensuing suction changes. Additionally, unlike the fully coupled flow-deformation analysis, the excess pore water pressure due to the load application in the uncoupled approach cannot be simulated [24]. Formation of the soil distorted mounds underneath the slab foundation in the coupled approach is thus correctly influenced by the combined effect of the suction evolution and the stresses induced by the footing loading.…”

“…Many researchers assume that the air pressure is constant during the flow-deformation analysis [e.g. 24,27,28], and the same approach is adopted in the current study.…”

“…It should be noted that most available FE studies on the topic of simulating the volume change of expansive soils are based only on the suction and stress variations [e.g. 17,19,24,29], with no consideration to the soil mineralogy. However, the soil minerals should be included as well; for example, clayey soils without highly swelling minerals in the form of montmorillonite are of no danger when exposed to high suction variation.…”

“…Dafalla et al [23] proposed a simplified design concept for a rigid substructure foundation in the form of an inverted-T of a two-storey concrete frame structure on expansive soils, and the edge heave scenario was simulated, while the centre heave scenario was omitted from the analysis. Zhang et al [24] carried out a coupled finite element transient analysis for isolated footings on expansive soils by adopting the thermal analogy, and the work focused on the prediction of soil movement due to the evapotranspiration of grass roots and crops, involving specific vegetation data, which in most cases would not be available to geotechnical engineers.…”

Numerical Modeling of Water Flow in Expansive Soils with Simplified Description of Soil Deformation

“…It can be expressed with respect to the gravimetric water content w (mass of water / mass of soil skeleton), the volumetric water content θ (volume of water / volume of soil) or water saturation S r (volume of water / volume of pores). In expansive and compressible soils, the shape of these functions is significantly affected by volume changes occurring during wetting and drying and by the external stress applied to the soil sample (Zhang and Briaud 2015).…”