Saturday, August 21, 2010

Sand Cone

FIELD DENSITY TEST OR SAND REPLACEMENT METHODE

gd = gt / (1+ w)
gd = Dry unit weight ( KN/ m3 )
gt = Total unit weight
w = Water content (%)





Test Equipments
  • Sand cone apparatus which consists of a one-gallon plastic bottle with a metal cone attached to it.
  • One-Gallon plastic can with cap.
  • Balance sensitive to 1 g.
  • Base plate
  • Tools for excavating a hole in the ground
  • Clean, uniformly graded sand ranging from #20 to #30 sieve such as Ottawa Sand
  • Proctor compaction mold without attached extension (used for calibration)
  • Plastic air-tight bag for carrying wet excavated soil from field to the lab.
  • Metal tray with a hole in the centre.
  • Oven with temperature kept about 105-110 .c.


Sand Cone Test Procedure :
Step 1- . Weight of Proctor mold, W1




Step 2a- Pouring the sand into the compaction mold
Step2b- Making the surface leveled





Step2c- Compaction mold filled out with sand



Step2c- Compaction mold filled out with sand



Step 2d-Weight of proctor mold + Sand, W2



Step 5. Weight of plastic Gallon+Cone+Sand (before use)



Step 6a-Close the valve of the cone attached to the cone





Step 6b- turn the cone and gallon upside down



Step 6c- open the valve, sand flows from the gallon to the cone, after the flow stops close the valve and take the gallon+cone from the tray



Step 6d- CNTD...




Step 6e- Weight of plastic Gallon+Cone+Sand (after use)



Step 8a- Weight of plastic Gallon+Cone+Sand (before use)



Step 8b- Go to the field where the soil's unit weight is to be measured and place the metal tray and fasten the 4 screws.



Step 8c- Dig up a hole about 10 to 15 cm deep.



Step 8d- As you are digging the hole put the retrieved soil into the plastic bag in order that the soil does not lose moisture.



Step 8e- All of the soil is transferred into the bag



Step 8f- The soft soil at the bottom of the hole is poured into the bag as well.



Step 8g- All of the soil is transferred into the bag



step 8h-Having the valve closed turn the gallon+cone upside down and place the cone in the center hole of tray and open the valve so that sand flows



Step 8i- sand flows CNTD... Unlike this photo plastic bag should be kept closed




Step 8j- After flow of sand stops close the valve and pick the assembly up, the sand in the cone will be poured into the tray.




Step 8k- CNTD



Step 8L- The sand in the hole and the overflow sand will be left in the field, grab all parts and get back to the lab.



Step 9- Weight of plastic Gallon+Cone+Sand (after use)



Step 11- Weigh the evaporating dish



step 12- Weigh the evaporating dish + wet soil from the field



Step 13- Put the evaporating dish + wet soil in the oven and after 24hrs weigh it again



Test Steps


Obtaining the unit weight of the sand used

1. Weight of Proctor mold, W1 = 4.178 kg

2. Weight of proctor mold + Sand, W2 = 5.609 kg

3. Volume of the mold, V1 = 0.00095 m3

4. Dry unit weight, gd (sand) = (W2 - W1) / V1 = 1506 kg/m3



Calibration cone

5. Weight of plastic Gallon+Cone+Sand (before use), W3 = 5.466 kg

6. Weight of plastic Gallon+Cone+Sand (after use), W4 = 3.755 kg

7. Weight of the sand to fill the cone, Wc = W4- W3 = 1.711 kg



Results from field tests

8. Weight of plastic Gallon+Cone+Sand (before use), W5 = 7.387 kg

9. Weight of plastic Gallon+Cone+Sand (after use), W6 = 3.919 kg

10. Volume of hole, V2 = (W5-W6-Wc)/ gd (sand) = 0.00117m3

11.Weight of evaporating dish, W7 = 0.507 kg

12. Weight of evaporating dish + wet soil from the field, W8 = 2.334 kg

13. Weight of evaporating dish + dry soil after 24hrs, W9 = 2.251 kg

14. Moist unit weight of the soil in the field, gt (in-situ soil) = (W8 - W7) / V2 = 1561 kg/m3

15. Water content in the field, w(%)= (W8 - W9) / (W9- W7)*100 = 4.76%

16. Dry unit weight in the field, gd (in-situ soil)= [gt (Row 14)] / [1+ w(%) / 100] = 1490 kg/m3





Conversion factors (Unit weight):
1000 kg/m3 = 9.81 KN/m3 = 62.4 lb/ft3





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