Soil–Water Characteristic Curve Variability

Abstract

Effect of wetting-drying cycles on a residual amphibolite soil's suction from western Medellin in a natural and compacted stateSlope stability is affected by a variety of physical and chemical phenomena, climate is one of the most relevant factors in this regard. In tropical areas there are great meteorological variations throughout the year, and surface soils are the most susceptible to changes in humidity and temperature that affect their behavior and resistance.To evaluate the influence of these variations, several moistening and drying cycles were developed for the soil of a road slope located west of the Aburra Valley. Laboratory tests were initially performed on undisturbed and compacted samples and subsequently on samples subjected to drip wetting and oven drying at 30 ° C. The physical and chemical characterization of the soil is initially carried out and the suction curve is measured by the filter paper method, the permeability and the resistance parameters for each wetting and drying cycle. The results showed that the soil suction gradually decreases with the number of wetting and drying cycles for both samples, more noticeable in the natural than in the compacted sample since the latter has a structure with smaller pores and the variations are perceived in less.The results of the research include a slope stability analysis that includes the hydraulic and resistance properties of both samples, obtaining a decrease in the safety factor after the wetting and drying cycles, compared to the initial sample, both for the natural and compacted sample.With the results, a step forward is taken in the study of mass movements triggered by rain since through the experimental methodology by which the moistening cycles are recreated from field data such as humidity, temperature and precipitation, it is can anticipate variation in parameters that influence slope stability.

Modelling resilient modulus seasonal variation of silty sand subgrade soils with matric suction control

“…Among the numerous empirical equations that can formulate the SWCCs, Fredlund and Xing's (1994) sigmoidal model has been widely used and validated for large ranges of soil types and suction values (Zapata et al, 2000). The model is expressed as: …”

Numerical analysis of matric suction effects of tree roots

“…The soil water characteristic curve used in this analysis is based on a relationship suggested by Zapata et al 32 A family of curves for different w 3 PI is shown in Fig. 13, where w is the fraction of soil passing sieve #200 (75 ìm) as an index between 0 to 1, and PI is the plasticity index.…”

Unsaturated Soils: Research and Applications

“…The calculated a, n parameters were correlated with soil index properties, and especially the weighted PI. Weighted PI (Zapata et al 2000) is defined as the product of the material passing the #200 U.S. Standard Sieve expressed as a decimal with the Plasticity Index expressed as a percentage. It was found that the a of the Brutsaert model or 1/a of the Burdine and Mualem models can be fairly described as a logarithmic expression of wPI.…”