Sand Replacement Method

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Description

Determine the unit weight of natural soil in place.

Stages
Determination of sand filling the cone
Determination bulk unit weight of sand
Determination bulk unit weight of natural soil

Procedure

Determining the weight of sand filling the cone

Sand passing through a 600µ sieve and retained over 300µ sieve is used.
Pouring cylinder attached over pouring cone is placed over level ground and completely filled with sand and weighed

The weight of sand + cylinder before pouring =푤_1

Now place the cylinder on the glass plate and open the shutter allow the sand to run out. Weigh the sand collected on the glass plate. This is the weight of sand filling pouring cone.

The weight of sand in pouring cone =푤_푐표푛푒
The weight of sand + cylinder after pouring on the glass =푤_2
The weight of sand in pouring cone =푤_푐표푛푒=푤_1−푤_2

Determination of bulk unit weight of sand

Determine the volume of the calibrated container (V)

Filled the pouring cylinder with weight 푤_1 again. Now placed over calibrating container and open the shutter, permit the sand to run into calibrating cylinder. When no further movement of sand is seen, close the shutter. �Remove the pouring cylinder and weigh it.

The weight of sand + cylinder after pouring into calibrated cylinder =푤_3

The weight of sand filling calibrated cylinder (푤_푐푐 )=푤_1−(푤_푐표푛푒+푤_3 ")"

Determination of bulk unit weight of natural soil

Exposed about 45 cm square area of the soil and trim it down to a level surface.
Keep the metal tray on the level surface and excavate a circular hole of 10 cm diameter and 15 cm depth.

The weight of excavated soil =푤^′

Remove the tray, and placed the sand pouring cylinder over the hole, the cylinder should have sand of weight 푤_1.

Open the shutter and permit the sand to run into the hole. Close the shutter when no movement of the sand seen.

Remove the cylinder and weigh the sand pouring cylinder.

The weight of sand +cylinder after pouring into hole =푤_4

The weight of sand in the hole 〖(푤〗_ℎ표푙푒)=푤_1−(푤_4+푤_푐표푛푒)

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1. SOIL MECHANICS
Sand Replacement
Method

2. L. 05 Determination of Unit Weight
4. Sand Replacement method
Determine the unit weight of natural soil in place.
Calibrating
container
10 cm internal diameter
15 cm internal depth
05 cm flange
3 litre capacity cylinder
Shutter
Cone
Metal Tray
Stages :-
1.Determination of sand filling the cone
2.Determination bulk unit weight of sand
3.Determination bulk unit weight of natural soil

3. L. 05 Determination of Unit Weight
Procedure :
•Sandpassingthrough600µsieveandretainedover300µsieveisused.
•Pouringcylinderattachedoverpouringconeisplacedoverlevelgroundandcompletelyfilledwithsand
andweighed
1. Determining the weight of sand filling the cone
Weight of sand + cylinder before pouring =�
1
•Now place the cylinder on the glass plate and open the
shutter allow the sand to run out. Weigh the sand collected on
the glass plate. This is the weight of sand filling pouring
cone.
Pouring cone
Shutter
Pouring cylinder
??????
�
Glass plate

4. L. 05 Determination of Unit Weight
Procedure :
•Sandpassingthrough600µsieveandretainedover300µsieveisused.
•Pouringcylinderattachedoverpouringconeisplacedoverlevelgroundandcompletelyfilledwithsand
andweighed
1. Determining the weight of sand filling the cone
Weight of sand + cylinder before pouring =�
1
Weight of sand in pouring cone =�
����
•Now place the cylinder on the glass plate and open the
shutter allow the sand to run out. Weigh the sand collected on
the glass plate. This is the weight of sand filling pouring
cone.
Weight of sand + cylinder after pouring on the glass =�
2
Weight of sand in pouring cone =�
����=�
1−�
2Or
Shutter
Pouring cylinder
??????
??????��??????
??????
�

5. L. 05 Determination of Unit Weight
2. Determination of bulk unit weight of sand
•Determine the volume of calibrated container (V)
•Filled the pouring cylinder with weight �
1again. Now
placed over calibrating container and open the shutter,
permit the sand to run into calibrating cylinder. When no
further movement of sand is seen, close the shutter.
Remove the pouring cylinder and weigh it.
Shutter
Pouring cylinder

6. L. 05 Determination of Unit Weight
2. Determination of bulk unit weight of sand
•Determine the volume of calibrated container (V)
•Filled the pouring cylinder with weight �
1again. Now
placed over calibrating container and open the shutter,
permit the sand to run into calibrating cylinder. When no
further movement of sand is seen, close the shutter.
Remove the pouring cylinder and weigh it.
�
��=0.785??????
2
??????
Shutter
Pouring cylinder
??????
????????????
??????
??????��??????
Weight of sand + cylinder after pouring into calibrated cylinder =�
3
??????
�
Weight of sand filling calibrated cylinder �
��=�
1−(�
����+�
3)
Bulk unit weight of sand
??????
????????????��=
�
�
=
�
��
�
��
=
�
1−(�
����+�
3)
0.785??????
2
??????

7. L. 05 Determination of Unit Weight
3. Determination of bulk unit weight of natural soil
•Exposed about 45 cm square area of the soil and trim it down to level surface.
•Keep the metal tray on the level surface and excavate a circular hole of 10 cm
diameter and 15 cm depth.
Weight of excavated soil =�
′
•Remove the tray, and placed the sand pouring cylinder over the hole, cylinder
should have sand of weight �
1.

8. L. 05 Determination of Unit Weight
3. Determination of bulk unit weight of natural soil
•Exposed about 45 cm square area of the soil and trim it down to level surface.
•Keep the metal tray on the level surface and excavate a circular hole of 10 cm
diameter and 15 cm depth.
Weight of excavated soil =�
′
•Remove the tray, and placed the sand pouring cylinder over the hole, cylinder
should have sand of weight �
1.
•Opentheshutterandpermitthesandtorunintothehole.Close
theshutterwhennomovementofthesandseen.

9. L. 05 Determination of Unit Weight
3. Determination of bulk unit weight of natural soil
•Exposed about 45 cm square area of the soil and trim it down to level surface.
•Keep the metal tray on the level surface and excavate a circular hole of 10 cm
diameter and 15 cm depth.
Weight of excavated soil =�
′
•Remove the tray, and placed the sand pouring cylinder over the hole, cylinder
should have sand of weight �
1.
•Removethecylinderandweighthesandpouringcylinder.
•Opentheshutterandpermitthesandtorunintothehole.Close
theshutterwhennomovementofthesandseen.
Weight of sand +cylinder after pouring into hole =�
4
Weight of sand in the hole (�
ℎ�??????�)=�
1−(�
4+�
����)
??????
??????�????????????
??????
??????��??????
??????
�

10. L. 05 Determination of Unit Weight
Volumeofsandinhole=
��??????�ℎ��������??????��??????��ℎ���(�
ℎ�??????�)
??????
????????????��
=
�
1−(�
4+�
����)
??????
????????????��
volume of sand in hole = volume of soil excavated from hole
�
1−(�
4+�
����)
??????
????????????��
=
��??????�ℎ��������������??????�(�
′
)
������??????���??????�ℎ�����??????�(??????)
??????=
�′×??????
????????????��
�
1−(�
4+�
����)
??????=
�′×??????
????????????��
�
ℎ�??????�