Soil sampling based on disturbed and undisturbed sampling

SOIL SAMPLING BASED ON DISTURBED AND UNDISTURBED SAMPLING VERIFICATION

The equipment and testing methodology produced erosion curves with repeatability that were superior with respect to their initial linear and transition portions. The soil loss curves presented hyperbolic behavior, with a maximum value that appeared to be randomly behaved, which can be attributed to the complex nature of the erosion processes at later stages.

Tests were performed on samples with void ratios of 1.0 and 1.5 and under variable hydraulic conditions to verify the repeatability and ideal analysis time for the soil loss curves. The apparatus and methodology were verified using statically compacted specimens of a latosol from the central region of Brazil. As a soil sample is removed from the ground during a conventional soil investigation, its insitu effective stress condition is being changed. Collecting a perfectly undisturbed sample. A rigorous analysis of the flow conditions during testing was considered and an interpretation of test results was carried out following the premises of the Water Erosion Prediction Project (WEPP) rill erosion model. Undisturbed soil samples retain the structural integrity of the soil and have a high recovery rate within the sampler.

SOIL SAMPLING BASED ON DISTURBED AND UNDISTURBED SAMPLING VERIFICATION

This paper presents the development and verification of an improved and cost-effective flume apparatus and corresponding testing methodology. The use of an intermediate layer acting as a capillary barrier did not offer significant improvement to the cover systems evaluated. Unimodal tropical soils presented adequate response as store-and-release materials. The results indicate that bimodal soils may not be ideal materials and require specific compaction conditions to reduce the volume of macropores. The results obtained were compared in terms of the internal flow and the capacity of the cover to store water. The thicknesses of intermediate materials were varied and different representative precipitation parameters were considered for a period of one year.

Any homeowner can collect soil samples by using a hand trowel to dig and remove soil to a depth of 6 inches in ten to twelve places within a lawn or garden. Among the proposed arrangements, three use a soil that presents a bimodal soil-water characteristic curve and the fourth system employs a unimodal soil. Aside from disturbed and undisturbed soil sampling, which is outside the scope of what most homeowners need for evaluating soil fertility, simple soil testing is the way to go. Numerical analyzes of four different cover systems composed of tropical soils were performed using the Finite Element Method. The objective of this paper is to evaluate the influence of the hydrological cycle and soil type on the performance of dry cover systems, considering the tropical conditions found in Brazil's central-west region. In relatively dry climates, dry soil covers have been considered as feasible alternatives to minimise such effects. The transport parameters for nitrate determined in disturbed and undisturbed samples were significantly different and the model was able to simulate the observed breakthrough curves after fitting the pore connectivity parameter.The flow of water in mining waste may cause serious environmental impacts associated with acid-rock drainage. Data obtained from the undisturbed samples showed a higher dispersion, suggesting homogenization of pore geometry and a reduction in the representative elementary volume by the disaggregation and sieving of the soil material. natural soil samples were tested, where the degree of disturbance influence on the obtained SWCC was discussed. Soil water retention curves and miscible displacement parameters were determined in breakthrough experiments with nitrate salts in columns filled with undisturbed and disturbed soil samples. An existing model for prediction of breakthrough curves based on retention properties was tested using material from a medium-textured Ferralsol, and alterations caused by sample disturbance were investigated. Disturbed samples are generally obtained to determine the soil type, gradation, classification, consistency, moisture-density relations (Proctor), CBR, presence. Structural alteration of the disturbed material implies modifications in the pore geometry that determines hydraulic properties, including hydraulic conductivity and retention and properties related to miscible displacement. Experiments with undisturbed samples are uncommon, due to the difficulty of taking undisturbed samples at the size required for these experiments. Solute transport parameters can be determined in miscible displacement experiments, usually performed in columns with disturbed (sieved) soil samples. LГvia Previatello da Silva, Quirijn de Jong van Lier, Marcus Metri Correa, Jarbas Honorio de Miranda, Luciano Alves de OliveiraДOI: 10.1590/18069657rbcs20151045 ABSTRACT Soil Processes and Properties Soil Physics Retention and Solute Transport Properties in Disturbed and Undisturbed Soil Samples

Soil sampling based on disturbed and undisturbed sampling