GrainSize 
The purpose of the GrainSize dialog is to store information related to the particlesize 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 soilwater characteristic curve (SWCC) for the material.
Data Type The user is allowed to select whether the data type is measured or estimated. Estimated grainsize 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 particlesize 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.
GrainSize 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 D42254T testing standard.
Unimodal Fit Tab The Unimodal Fit tab contains all information related to the fit of the grainsize distribution with the unimodal equation.
Bimodal Fit Tab The Bimodal Fit tab contains all information related to the fit of the grainsize 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 grainsize 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 grainsize data. A prerequisite for the calculations is that a method of representing the grainsize distribution must first be selected.
Insert Button The Insert button is used to insert data points into the grainsize 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.
