In-situ regolith depth measurements by DPL tests

Gomes, Guilherme José Cunha; Araújo, João Paulo Carvalho; Vargas, Eurípedes do Amaral; Fernandes, Nelson Ferreira

doi:10.20906/cps/gj-01-0035

Cited by 2 publications

(6 citation statements)

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“…The two functions suggest an excellent water holding capacity of the soil mantle, with pressure heads that must be below À80 cm for air to enter the pores. This finding is consistent with our soil textural data, which demonstrate relatively high percentages of silt and clay [42]. The confidence interval of the SWCC is almost perfectly symmetrical, being similarly large at saturation and the residual moisture content, and smallest in the interval between the two inflection points (moisture contents between 0.2 and 0.4 cm 3 /cm 3 ).…”

Section: Uncertainty In the Soil Hydraulic Propertiessupporting

confidence: 92%

“…3, the use of a larger number of elements (and thus nodes) hardly changes the numerical results of our flow model. Since our measurements of the soil mantle did not reveal the presence of a well-defined stratigraphy with multiple layers [42], we conveniently assumed the hillslope interior to be homogeneous. Nonetheless, our MATLAB flow model can solve for water movement in heterogeneous soil-bedrock domains, if deemed appropriate.…”

Section: Temporal and Spatial Discretizationmentioning

confidence: 99%

“…The eight black circles represent locations where additional soil samples were collected via drilling with a mechanical auger. We refer to [42] for a detailed description of the field campaign and measurements.…”

Section: Uncertainty Of Bedrock Topographymentioning

confidence: 99%

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The role of uncertainty in bedrock depth and hydraulic properties on the stability of a variably-saturated slope

Gomes

Vrugt

Vargas

et al. 2017

Computers and Geotechnics

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a b s t r a c tWe investigate the uncertainty in bedrock depth and soil hydraulic parameters on the stability of a variably-saturated slope in Rio de Janeiro, Brazil. We couple Monte Carlo simulation of a threedimensional flow model with numerical limit analysis to calculate confidence intervals of the safety factor using a 22-day rainfall record. We evaluate the marginal and joint impact of bedrock depth and soil hydraulic uncertainty. The mean safety factor and its 95% confidence interval evolve rapidly in response to the storm events. Explicit recognition of uncertainty in the hydraulic properties and depth to bedrock increases significantly the probability of failure.

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Section: Uncertainty In the Soil Hydraulic Propertiessupporting

confidence: 92%

Section: Temporal and Spatial Discretizationmentioning

confidence: 99%

See 1 more Smart Citation

The role of uncertainty in bedrock depth and hydraulic properties on the stability of a variably-saturated slope

Gomes

Vrugt

Vargas

et al. 2017

Computers and Geotechnics

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“…The penetration test locations (Fig. 2) were marked using a differential GPS, which determines the position of the points within the margin of error of 0.5 m (Gomes et al, 2016a).…”

Section: Gomes Et Al (2016amentioning

confidence: 99%

“…For more details about the penetration tests with the DPL in the eld and the criteria used to measure regolith thickness, see Gomes et al (2016a) and Nilsson and Cunha (2003), respectively. Vieira and Fernandes (2004) analyzed the soils of the region and presented results on trenches made in the eld close to ancient landslide scars, where the characteristics of the regolith vary from a mature soil with well-de ned A and B horizons to deposits of heterogeneous talus and coarse materials.…”

Section: Gomes Et Al (2016amentioning

confidence: 99%

Application of Empirical Modeling to Predict the Spatial Distribution of Soil Thickness in a Mountainous Region with Deep Regolith

de Almeida,

Araújo,

Fernandes

et al. 2024

Preprint

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Predicting the spatial variation of soil thickness is essential to improve our understanding different hydrological and geomorphological processes, such as landslides, surface runoff generation, and, consequently, erosional processes. The variable “soil thickness” is also crucial for engineering with a focus on excavations and the construction of underground structures. Despite its importance, estimating the spatial distribution of soil thickness in the field is not an easy task, especially in tropical areas with thick soil mantles and highly undulating topography. This study focuses on estimating the spatial distribution of soil thickness based on empirical models that use topographic parameters, such as elevation, hillslope angle, curvature, topographic position index, and topographic wetness index. The four models used were tested in the Papagaio river basin, in the city of Rio de Janeiro. Their parameterization and validation were implemented using data from 137 penetration tests carried out in the field with the usage of a light dynamic penetrometer (DPL), which indicates that the soil thickness may reach up to 15 m. The results provided information for a discussion concerning the strengths and limitations of each model. The best results were achieved by the model that considered the largest number of parameters to estimate soil thickness. The empirical models used here do not directly consider the erosional and depositional processes that occur in the landscape. Therefore, future studies should include more complex predictive models that are more adequate to the reality and complexity of this type of landscapes.

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In-situ regolith depth measurements by DPL tests

Cited by 2 publications

References 0 publications

The role of uncertainty in bedrock depth and hydraulic properties on the stability of a variably-saturated slope

The role of uncertainty in bedrock depth and hydraulic properties on the stability of a variably-saturated slope

Application of Empirical Modeling to Predict the Spatial Distribution of Soil Thickness in a Mountainous Region with Deep Regolith

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