Hello,
Soil is studied for its compressibility and is found to be compressible using to processes (a) Compaction (b) Consolidation
Compaction is the process of reducing the volume of the soil by applying the pressure using the mechanical means, and thereby removing the air voids present in the soil.
Compaction is done using in the filed using the instruments like rollers and rammers and using the optimum moisture content to achieve the maximum dry density.
Maximum dry density is determined in the laboratory first using the standard proctor test or modified proctor test and thus is found its OMC. In the field these values of the dry density and the OMC are taken as the references to control the compaction.
Consolidation is the process of reducing the volume of the soil under the application of some static load(A building/structure), by the expulsion of the water present in the pores of the saturated soil.
Consolidation is a very long process, reasons behind the delay in the expulsion of the pore water is due to very less permeability of the fine grained soil.
As the clayey soil is almost impermeable so it is hard to achieve the 100% degree of consolidation.
Consolidation Test:
Consolidation test is performed using the consolidation test apparatus. Generally the diameter to length ratio of the specimen prepared for this test is 3. The top and bottom of the cylindrical sample are closed with the porous stones and the pressure is applied normally to the circular faces.
Initially a minimum pressure is applied and it is generally kept for 24 hours to get consolidated. Pressure is increased and then again left to consolidate. When there is no remarkable decrease in the volume we can stop the test. A curve between the applied pressure and the change in the void ratio is drawn and the results are used to determine the following:
1)Compression Index:
After performing the test in the laboratory a curve is plotted between the void ratio and the log of the applied pressure. This curve is known as the compression curve.
Compression Index = Change in void ratio/ Corresponding change in the applied pressure on the logarithmic scale
2) Co-efficient of consolidation
Terzaghi's one dimension consolidation test:
Terzaghi gave the method to find out the co-efficient of consolidation Cv using the laboratory test performed to draw the curve between the Degree of consolidation(U) and the time(Tv) and relate the theoretical and the practical results to determine the co-efficient of consolidation.
Thanks!
Soil is studied for its compressibility and is found to be compressible using to processes (a) Compaction (b) Consolidation
Compaction is the process of reducing the volume of the soil by applying the pressure using the mechanical means, and thereby removing the air voids present in the soil.
Compaction is done using in the filed using the instruments like rollers and rammers and using the optimum moisture content to achieve the maximum dry density.
Maximum dry density is determined in the laboratory first using the standard proctor test or modified proctor test and thus is found its OMC. In the field these values of the dry density and the OMC are taken as the references to control the compaction.
Consolidation is the process of reducing the volume of the soil under the application of some static load(A building/structure), by the expulsion of the water present in the pores of the saturated soil.
Consolidation is a very long process, reasons behind the delay in the expulsion of the pore water is due to very less permeability of the fine grained soil.
As the clayey soil is almost impermeable so it is hard to achieve the 100% degree of consolidation.
Consolidation Test:
Consolidation test is performed using the consolidation test apparatus. Generally the diameter to length ratio of the specimen prepared for this test is 3. The top and bottom of the cylindrical sample are closed with the porous stones and the pressure is applied normally to the circular faces.
Initially a minimum pressure is applied and it is generally kept for 24 hours to get consolidated. Pressure is increased and then again left to consolidate. When there is no remarkable decrease in the volume we can stop the test. A curve between the applied pressure and the change in the void ratio is drawn and the results are used to determine the following:
1)Compression Index:
After performing the test in the laboratory a curve is plotted between the void ratio and the log of the applied pressure. This curve is known as the compression curve.
Compression Index = Change in void ratio/ Corresponding change in the applied pressure on the logarithmic scale
2) Co-efficient of consolidation
Terzaghi's one dimension consolidation test:
Terzaghi gave the method to find out the co-efficient of consolidation Cv using the laboratory test performed to draw the curve between the Degree of consolidation(U) and the time(Tv) and relate the theoretical and the practical results to determine the co-efficient of consolidation.
Thanks!
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