Issues of effectiveness in empirical methods for describing swelling soils (original) (raw)
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Data acquired from the hyperspectral airborne sensor DAIS-7915 over Antequera in southern Spain was processed to yield a quantitative soil swelling potential map based on three physicochemical soil properties currently used in engineering as measures of soil swelling namely cation exchange capacity (CEC), coefficient of linear extensibility (COLE), and Saturated moisture content (SP). The method adopted was the use of the statistical procedures of cluster analysis and factor analysis to obtain spectral parameters with a potential to classify the soils into classes based on existing classification thresholds of the three properties where laboratory, field and image extracted pixel spectral data analysis were used. Applying this on a pixel-by-pixel basis revealed images that described spatially and qualitatively the surface distribution of these properties and thus swell potential differences among the soils in the area. The results gave an indication of the possible use of airborne spectral data for swell potential estimation.
Effectiveness of spectroscopy in identification of swelling indicator clay minerals
International Journal of Remote Sensing, 2004
Swelling soils are a major geological hazard worldwide and their identification is a major concern. Swelling is due to the presence of clay minerals with a potential to accommodate water within their crystal structure. Three common groups, namely smectite, illite and kaolinite, have been identified as indicators of high, moderate and low swelling potential soils where in abundance. This study assessed the potential of spectral data as a tool to recognize the presence of these minerals in soils of varying swelling potential collected from the Antequera area of southern Spain, with the aim of establishing spectral parameters that would in future be applied in remote sensing applications for mapping swelling soils. The coefficient of linear extensibility (COLE) and the linear extensibility (LE rod ), which are established methods for assessing swelling potential and tentative clay mineral allocation, were used as the controlling methods to classify the soils into swelling potential groups and to assign them to dominant clay mineral types. Several spectral parameters were identified as giving a good basis for assigning the soils to domination by either of these clay minerals, and thus to a swelling potential class based on their diagnostic assignment to hydroxyl (OH) and molecular water vibrational processes in clay minerals. The parameters consisted of asymmetries (1400 nm and 2200 nm) that were strong in the presence of the more ordered kaolinite, wavelength position and depth at 1900 nm in abundant smectites, first and second derivative peaks at or near the molecular water feature and the unique presence of absorptions at 2170 nm and 2340 nm in abundant kaolinite and illite. The results show the potential for using reflectance spectroscopy as a tool in the classification of soils into domination by these indicator minerals and thus into swelling potential classes. However, high organic matter and the presence of moisture were found to affect area and depth intensities and would require consideration in such applications.
Indirect Estimation of Swelling Clay Soils Parameters
In this article, a literature review of statistical models giving the parameters of swelling clay soils in relation to other geotechnical parameters whose determination is easily given. These models were then applied to our database which consists of 35 free swelling tests performed on reconstituted samples. This application has shown that it is difficult to generalize these models to any type of soil. We also proposed specific models in our tests taking into account the increasing of the factors number. The results have show that the pressure correlates better than the amplitude and the inclusion of a higher number's parameters in the model improving the later performance.
Estimation of swelling characteristics of expansive soils with influence of clay mineralogy
Acta Agriculturae Scandinavica, Section B — Soil & Plant Science, 2021
ABSTRACT In the present study, characterisation and quantitative microanalysis were identified for six expansive soils of which one is natural soil, i.e. black cotton (BC) soil and remaining soils were prepared by mixing of BC soil with different percentage of bentonite. The BC soil and prepared soil samples were characterised by the X-ray diffraction (XRD) and scanning electron microscope (SEM). The regular or irregular mixed layers of soils justified by SEM images. There are superstructures whose spacing can simply be described as the ratio of BC soil and prepared soil. d-Spacing was calculated by Bragg’s formula (XRD) which was observed by joint committee on powder diffraction standards card and calculated by Bragg’s equation for h-k-l plane for expansive soils and it was observed that d-spacing decreased with increasing prepared soil combination. Moisture content was taken below optimum moisture content, i.e. 15%, 17% and 20% to determine swelling and swelling pressure and found that montmorillonite mineral affects the swelling characteristics of expansive soils.
The identification of swelling potential of soils assumes significant importance in checking the possible post-construction problems for the structures. Due to steep increase in construction activities in the recent times, there is a need for quick and simple method to facilitate the civil engineers in evaluating and identifying the expansiveness and swelling potential of soils. Utilizing the index and grain size properties of soils, the authors have developed two matrices and two group charts, to identify the soils that are problematic for civil engineering projects. The positions of soil samples in any of the two matrices may be fixed column wise and row wise depending on their index and grain size properties. The characters of black cotton soils from Hubballi-Dharwad Municipal Corporation area, Karnataka, India are used to determine their positions in matrices and group charts developed and the problematic soils are then identified. The proposed new technique is extended to soils...
International Journal of Research and Analytical Reviews (IJRAR), 2019
Expansive soils expand and shrink after they absorb wet exhibiting moderate to terribly high shrink-swell potential that influences the index properties of soil. Thus swell Potential helps to determine the analysis and style of structures created on expansive soils. The main objective of this review article is formed during this criticism that evaluates expedient methodologies for probably expansive soils and assessment of the techniques used for classification functions. The results of the analysis of revealed techniques disclose that the most effective techniques and so the most effective indicators of potential swell are the liquid limit and plasticity index. Alternatively the important indicator properties in raining order are liquid limit and natural water content combined with shrinkage limit and plasticity index and shrinkage limit and linear shrinkage. It is concluded that the laboratory knowledge are analyzed to work out further properties which can sensitively indicate the degree of potential swell in physical, chemical and typical association of swell characteristic parameters. The soil behavior is predicted by considering the soil state and soil sort connected by the environmental factors specifically initial wet Content, unaltered Dry Density and integrative parameters like Liquid Limit and plasticity Index. From this review, it are often all over to know the importance of combinations of physical/chemical, and mineralogical measurements in classifying the soil vulnerability to swelling and also the quality of swelling potential estimation.
Determination of soil properties using of spectroscopic method
Journal of Biology and Medicine: Open Access , 2020
As a non-destructive, fast, low-cost technique with the minimum preparation of samples and no risk for ecosystem, visible near infra-red spectroscopy may be replaced with methods using in vitro. The current research aims to assess reflective spectroscopy in estimation of properties of soils locating ion farming plains at Tehran, Khuzestan, and Yazd provinces. To this end, 88 soil samples were collected from the studied zones and their basic properties were calibrated using standard techniques in vitro. The spectral analysis of soils was done using land spectroscopic device at wavelengths (240-400 nm). The types of preprocessing techniques were assessed after recording of spectra and PCA and PLSR models were utilized to determine main properties of soil. The best method was used for estimation of regressive functions to predict studied parameters after linear regression. The findings showed that both PCA and PLSR models had high precision for determination of parameters of soil properties and they could interpret high variances of soil properties and PLSR model was more precise than PCA model. With respect to RPD statistic the best estimation of the offered regressive functions was calculated for minerals (RPD=9.34), pH (RPD=4.45), and nitrogen (RPD>2) each of these three factors were classified in series-A and the lower estimations were computed for clay, silt, gravel, quantities of phosphorus, potassium, calcium, and magnesium, and gypsum within the range of (RPD=0.01-0.28). These numbers denote reasonable precision of spectral regressive functions in prediction of studied basic properties. Overall, results of this study indicate that both PCA and PLSR models have appropriate precision in determination of main parameters of soil properties and also the soil spectral data may be utilized as an indirect technique for estimation of soil physical and chemical properties and in comparison with laboratory methods this technique is more economical to determine chemical and physical properties in terms of time and cost-effectiveness with higher precision.
Spectral classification of soils: A case study of Brazilian flooded soils
Remote Sensing Applications: Society and Environment, 2017
Studies on the spectral behavior of Brazilian soils and their possible applicability to increase productive efficiencies are still scarce, mainly for paddy soils, present in a small part of the territory and yet very important for agricultural production in the country. The objective of work was to obtain parameters for classification of paddy soils using spectral data obtained by diffuse spectroradiometry. The surface and subsurface soil samples were collected by using a 90 m 2 sampling grid with equidistant points. Spectral analysis was performed in a laboratory by using a spectroradiometer with 1 nm resolution at 350-1100 nm and 2 nm resolution at 1100-2500 nm. The evaluation of spectral curves was performed on the basis of four different procedures. The statistical analysis was performed by using the procedures STEPDISC, STEPWISE, and DISCRIM of Statistical Analysis System (SAS) software. The results show that soil discriminations by the spectral data obtained in the laboratory were successful. However, the model that tests the procedure for soil discrimination has low accuracy of 47.79% when compared with other methods.