Moisture Movement Through Cracked Clay Soil Profiles

Abstract

A continuum mechanics approach is used for the formulation of unsaturated hydraulic conductivity functions and the water storage functions for fractured or cracked clay soils in this parametric study. Suggested procedures are based on available research literature related to the behavior of cracked unsaturated porous media. The soil-water characteristic curve, hydraulic conductivity and water storage functions take on the character of bi-modal unsaturated soil property functions. The bimodal character arises out of the independent behavior of the cracks and the intact clay soil. Matric suction changes beneath a slab-on-grade foundation placed on a cracked clay soil profile are modeled for varied surface flux conditions using the proposed unsaturated hydraulic conductivity and water storage functions. The impact of various levels of surface cracking on soil suction distributions is discussed. Suction distribution patterns are dependent on the initial soil surface suction. In particular, the results are dependent upon whether the initial matric suction is less than or greater than the air entry of the cracked clay. There is an extremely wide range of possible conditions that could be modeled but the parametric study results presented in this paper are limited to a series of selected crack widths and densities for an exfiltration case and an infiltration case.

Construction, management and maintenance of embankments used for road and rail infrastructure: implications of weather induced pore water pressures

“…This suggests that traditional single porosity SWRC models [43,44] will not capture the in-situ SWRC of a cracked soil and instead it would be necessary to account for this behaviour using some form of dual porosity model such as that proposed by Durner [45] or by Fredlund et al [46].…”

Porosity Reviewed: Quantitative Multi-Disciplinary Understanding, Recent Advances and Applications in Vadose Zone Hydrology

“…15). Fredlund et al (2010) elaborate on the commencement of cracking in clayey soils from ground surface with increasing matric suction. They evaluate the soil-moisture characteristic curves for intact clay, cracked soil mass and finally the cracked portion alone.…”

Investigation of Aqueous and Non-Aqueous Phase Liquids Migration in Fractured Double-Porosity Soil

“…It is well known that soil is typified by many different structures, and that soils characteristics are roughly not homogeneous. Fractured soil reduced the intact soil shear strength and increased the hydraulic conductivity [3]. Krisnanto et al [4] stated that the cracked soil played an essential role in the flow of liquids through problematic soil.…”

“…Krisnanto et al [4] stated that the cracked soil played an essential role in the flow of liquids through problematic soil. The hydrological behaviour and mechanical properties in fractured soil are significantly changed [3]. It is widely acknowledged that the soil with intraaggregate and inter-aggregate pores for double-porosity soil display pore-size bimodal distribution that can found in agricultural tops-soils and compacted soil [5] and [6].…”

“…Research by Barenblatt et al [10] found that the overlapping continuum technique had been the basis theory for the doubleporosity soil. Moreover, Fredlund et al [3] show that fractured soils based on a continuum mechanics approach is used for inception of unsaturated liquid storage and conductivity functions. In addition, the dual-continuum method is capable of dealing more methodically with fracture matrix interplay compared to discrete-fracture model [3].…”