Grain-Size

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SVSoils

 

 

The purpose of the Grain-Size dialog is to store information related to the particle-size distribution of a soil. The % sand, % silt, % clay, and % coarse values are stored for the USDA or the USCS methods of classification. Unimodal and Bimodal equations provide a continuous mathematical representation of the material which can be used for subsequent statistical calculations as well as the estimation of the soil-water characteristic curve (SWCC) for the material.

 

Data Type

The user is allowed to select whether the data type is measured or estimated. Estimated grain-size data is based on % clay, % silt, % sand, and % coarse values.

 

Calculation Method

The Unimodal calculation method allows the user to select the type of equation that will be used to fit the particle-size data.

Unimodal: The Unimodal equation fits an equation through sieve data where there is a single dominant particle size. Please refer to the SVSOILS Theory Manual for a description of the theory involved with the unimodal equation.

 

Bimodal: The Bimodal equation fits an equation through data where there are two dominant particle sizes in the material. Please refer to the SVSOILS Theory Manual for a description of the theory involved with the bimodal equation.

 

Data: The data calculation method fits an equation using the sieve data.

 

Grain-Size Data Tab

The Grain Size Data tab contains the information related to the recording of a sieve analysis on a soil sample. Sieve data can be entered in terms of particle diameter and percent passing. The cumulative weight and phi, fields are then calculated. Please refer to the SVSOILS Theory Manual for a description of the phi parameter. Test data is recorded in accordance with the ASTM D422-54T testing standard.

 

Unimodal Fit Tab

The Unimodal Fit tab contains all information related to the fit of the grain-size distribution with the unimodal equation.

 

Bimodal Fit Tab

The Bimodal Fit tab contains all information related to the fit of the grain-size distribution with the bimodal equation.

 

Percentages Tab

The Percentage tab is used to store the % coarse, % sand, % silt, and % clay values for both the USDA and USCS methods of classification.

 

Statistics Tab

The Statistics tab contains all statistical calculations based on the grain-size distribution for a single soil. The effective grain diameter is calculated according to the formula presented for the Zamarin (1992) estimation of saturated permeability. Please refer to the SVSOILS Theory Manual for a description of the theory associated with the calculation of the particle size statistics on a single soil.

 

General Tab

The General tab contains information such as the testing standard, test method, laboratory name, laboratory location and laboratory notes that should be entered prior to entering sieve or hydrometer data. The date of the laboratory test should also be entered.

 

Apply Fit Button

The Apply Fit button initiates the algorithm that should be used to fit the appropriate equation to laboratory data.

 

Calculation Button

The Calculation button initiates the calculation of grain-size data. A prerequisite for the calculations is that a method of representing the grain-size distribution must first be selected.

 

Insert Button

The Insert button is used to insert data points into the grain-size data.

 

Paste Button

The Paste button is used to paste data points that are present on the clipboard.

 

Delete Button

The Delete button is used to delete laboratory data points that have been entered in error. Such points can be deleted by selecting the point and pressing the Delete button.

 

Delete All Button

The Delete All button is used to delete all data points entered.