Testing

Thursday, December 15, 2016

Density of Soil In-Place by the Sand Cone Method {Field Density Test (FDT)}


Density of Soil In-Place by the Sand Cone Method {Field Density Test (FDT)}

Description
         This method of test is intended for determining the in-place density of soils. The apparatus described herein is restricted to tests in soils containing particles not larger than 50 mm (or 2 in.) in diameter.
         The principle involved is to remove a sample of soil from the area for which the in-place density value is desired, measure the volume of the hole produced and determine the mass and moisture content of the sample removed.

      Apparatus 
     Density Apparatus
                The density apparatus shall consist of a 4 liter (1 gal.) jar and a detachable appliance consisting of a cylindrical valve with an orifice 12.7 mm (1/2 in.) in diameter and having a small funnel connected to a standard G mason jar top on one end and a large funnel on the other end. The valve shall have stops to prevent rotating the valve past the completely open or completely closed positions

 Preliminary Procedure
      Determine the volume of the calibrated measure by filling with water and weighing. The temperature of the water shall be determined. The net mass of the water used to fill the measure divided by the density of the water at the test temperature equals the volume of the measure

Determine the bulk density (unit mass) of the standard sand to be used as follows

          Fill the sand cone apparatus with the standardized sand and invert the cone on the calibrated measure, open the valve at the neck of the cone and allow the sand to run freely into the measure. When the sand ceases to move in the jar, close the valve and raise the sand cone and jar vertically away from the measure. Using the straightedge, strike the sand off level with the top of the measure with as few strokes as possible. Use extreme care not to jar or shake any of the apparatus during this operation as this would tend to rearrange sand particles and provide wrong unit mass. Weigh the calibrated measure and the sand. The unit mass (bulk density) of the sand equals the mass of the sand and measure minus the mass of the measure divided by volume of measure. Repeat this process two or three times or until consistent results are obtained.

 Field Procedures
      Determine the mass of the jar and attachment up to and including the volume of the valve orifice as follows
        Place the empty apparatus upright on a firm level surface, close the valve and fill the funnel with sand.
      Open valve and, keeping funnel at least half full of sand, fill the apparatus. Close valve sharply and empty excess sand from funnel.
       Weigh the apparatus and sand, and record as mass of initial sand plus' apparatus.
     The mass determined in this procedure is constant as long as the jar and attachment are in the same relative position. If the two are to be separated match marks should be made to permit reassembly to this position.
      Determine the mass of sand required to fill the funnel as follows .
     Put sand in the apparatus and determine the mass of apparatus and sand .Seat the inverted apparatus on a clean, level, plane surface.
      Open the valve and keep open until after the sand stops running.
Close the valve sharply, weigh the apparatus with remaining sand and determine the loss of sand. This loss represents the mass of sand required to fill the funnel.
      Replace the sand removed from the jar in the funnel determination and close the valve

Calculations
  Calculate the volume of the calibrated measure as follows
            
                V1=M/dt
where:
V1 = volume of the calibrated measure, cm3 ,
M = mass of water required to fill calibrated measure, g, and
dt = density of water at temperature of filling, g/cm3 .
Calculate the bulk density of the sand as follows

             W1=W2/V1
where:
W1= bulk density of the sand, g/cm3 ,
W2 = mass of sand required to fill the calibrated measure g, and
V1 = volume of calculated measure,

Calculate the moisture content and the dry mass of material removed from the test hole as follows
where:
 w = percentage of moisture, in material from test hole, 
W3 = moist mass of moisture sample, g. 
W4, = dry mass of moisture sample, g 
W5 = moist mass of the material from the test hole, g, and, 
W6, = dry mass of material from test hole, g

Calculate the in-place dry density of the material tested as follows:
where: 
V = volume of test hole, cm3 , 
W7 = mass of sand used g, 
W8 = mass of sand in funnel  g, and 
W = dry density of the tested material, g/cm3

DOWNLOAD EXCEL SHEET FOR FIELD DENSITY TEST

Here is the down;load link for fdt test. In this sheet every formula is present. You have to only put weight of Soil , Sand and Moisture content after this automatically compaction will be calculated.


                   ------END-----



     


0 comments:

Post a Comment