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Sand Replacement Method
The document outlines a procedure for determining the unit weight of natural soil using the sand replacement method. This includes detailed steps for calibrating equipment, filling a pouring cylinder, measuring bulk unit weights of sand and natural soil, and calculating the necessary weights and volumes. The goal is to accurately assess the bulk unit weight of in-place soil through systematic measurements and calculations.
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Sand Replacement Method
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- 2. L. 05 Determinationof 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 Determinationof Unit Weight Procedure : • Sand passing through 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 1. Determining the weight of sand filling the cone Weight of sand + cylinder before pouring = 𝑤1 • 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 𝒘 𝟏 Glass plate
- 4. L. 05 Determinationof Unit Weight Procedure : • Sand passing through 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 1. Determining the weight of sand filling the cone Weight of sand + cylinder before pouring = 𝑤1 Weight of sand in pouring cone = 𝑤𝑐𝑜𝑛𝑒 • 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 = 𝑤2 Weight of sand in pouring cone = 𝑤𝑐𝑜𝑛𝑒 = 𝑤1 − 𝑤2Or Shutter Pouring cylinder 𝒘 𝒄𝒐𝒏𝒆 𝒘 𝟐
- 5. L. 05 Determinationof Unit Weight 2. Determination of bulk unit weight of sand • Determine the volume of calibrated container (V) • Filled the pouring cylinder with weight 𝑤1 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. Shutter Pouring cylinder
- 6. L. 05 Determinationof Unit Weight 2. Determination of bulk unit weight of sand • Determine the volume of calibrated container (V) • Filled the pouring cylinder with weight 𝑤1 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. 𝑉𝑐𝑐 = 0.785𝐷2 𝐻 Shutter Pouring cylinder 𝒘 𝒄𝒄 𝒘 𝒄𝒐𝒏𝒆 Weight of sand + cylinder after pouring into calibrated cylinder = 𝑤3 𝒘 𝟑 Weight of sand filling calibrated cylinder 𝑤𝑐𝑐 = 𝑤1 − (𝑤𝑐𝑜𝑛𝑒 + 𝑤3) Bulk unit weight of sand 𝛾𝑠𝑎𝑛𝑑 = 𝑊 𝑉 = 𝑤𝑐𝑐 𝑉𝑐𝑐 = 𝑤1 − (𝑤𝑐𝑜𝑛𝑒 + 𝑤3) 0.785𝐷2 𝐻
- 7. L. 05 Determinationof 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 = 𝑤′ • Remove the tray, and placed the sand pouring cylinder over the hole, cylinder should have sand of weight 𝑤1.
- 8. L. 05 Determinationof 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 = 𝑤′ • Remove the tray, and placed the sand pouring cylinder over the hole, cylinder should have sand of weight 𝑤1. • Open the shutter and permit the sand to run into the hole. Close the shutter when no movement of the sand seen.
- 9. L. 05 Determinationof 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 = 𝑤′ • Remove the tray, and placed the sand pouring cylinder over the hole, cylinder should have sand of weight 𝑤1. • Remove the cylinder and weigh the sand pouring cylinder. • Open the shutter and permit the sand to run into the hole. Close the shutter when no movement of the sand seen. Weight of sand +cylinder after pouring into hole = 𝑤4 Weight of sand in the hole (𝑤ℎ𝑜𝑙𝑒) = 𝑤1 − (𝑤4 + 𝑤𝑐𝑜𝑛𝑒) 𝒘 𝒉𝒐𝒍𝒆 𝒘 𝒄𝒐𝒏𝒆 𝒘 𝟒
- 10. L. 05 Determinationof Unit Weight Volume of sand in hole = 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑠𝑎𝑛𝑑 𝑓𝑖𝑙𝑙𝑖𝑛𝑔 ℎ𝑜𝑙𝑒(𝑤ℎ𝑜𝑙𝑒) 𝛾𝑠𝑎𝑛𝑑 = 𝑤1 − (𝑤4 + 𝑤𝑐𝑜𝑛𝑒) 𝛾𝑠𝑎𝑛𝑑 volume of sand in hole = volume of soil excavated from hole 𝑤1 − (𝑤4 + 𝑤𝑐𝑜𝑛𝑒) 𝛾𝑠𝑎𝑛𝑑 = 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑒𝑥𝑐𝑎𝑣𝑎𝑡𝑒𝑑 𝑠𝑜𝑖𝑙 (𝑤′) 𝑏𝑢𝑙𝑘 𝑢𝑛𝑖𝑡 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓 𝑠𝑜𝑖𝑙 (𝛾) 𝛾 = 𝑤′ × 𝛾𝑠𝑎𝑛𝑑 𝑤1 − (𝑤4 + 𝑤𝑐𝑜𝑛𝑒) 𝛾 = 𝑤′ × 𝛾𝑠𝑎𝑛𝑑 𝑤ℎ𝑜𝑙𝑒