Experiment No. 12: Soil Consolidation
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Determination of one-dimensional consolidation parameters of an undisturbed cohesive soil sample.

Consolidation cell, Ring, Porous stones, Loading frame and dial gauge, Water reservoir, Trimming tools,
Balance, Filter paper, Stop-watch, Apparatus for moisture content determination.

1. Clean the consolidation ring and measure its inside diameter, height and weight.

2. Press the ring gently into the undisturbed soil sample until soil projects above the top of the ring, lift it up with extreme care, and trim the soil surfaces flush both at the top and bottom of the ring. Remove any excess soil sticking outside, and weigh the specimen with ring. Take samples from the remaining soil mass for determination of initial water content.

3. Place soaked porous stones on the top and bottom surfaces of the soil specimen with filter paper discs in between. Press lightly to ensure that the stones adhere to the specimen.

4. Assemble the specimen carefully into the consolidation cell, mount the cell on the loading frame, and set the dial gauge. Connect the system to a water reservoir, and allow the water to flow into till the specimen is completely covered and saturated.

5. Adjust and record initial dial gauge reading. Apply normal load to give a pressure intensity of 0.1 kg/cm2 on the soil specimen.

6. Note the dial gauge readings at elapsed times of 0, 0.25, 1, 2.25, 4, 6.25, 9, 12.25, 16, 20.25, 25, 36, 49, 64, 81, 100, 169, 256, 361, etc. up to 24 hrs.

7. Increase the normal load to double of the previous pressure intensity as in step 5, and take dial gauge readings at the same elapsed time intervals as in step 6. Use a loading sequence of 0.1, 0.2, 0.4, 0.8, 1.6, 3.2 kg/cm2, etc.

8. On completion of the final loading stage, decrease the load to ¼ of the last load, allow it to remain for 24 hours, and then note the dial gauge reading. Reduce further the load in steps of one-fourth the previous load and repeat the observations. If data for repeated loading is required, increase the load intensity and take dial readings.

9. After recording the final time and dial reading, siphon water out of the consolidation cell, release the load, quickly disassemble the cell, remove the ring, and blot the specimen surfaces dry with paper

10. Weigh the specimen with ring, and place in the oven for determination of final water content.

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