CONSTANT RATE OF STRAIN METHODS CONSOLIDATION TEST

                                             CONSTANT  RATE OF STRAIN METHODS CONSOLIDATION TEST

    The problem that needs to be considered when building on soft land is compression as a result of the consolidation event. Consolidation compression is a compression caused by water discharge from the soil pore due to the addition of load on the ground surface. Compaction of consolidation is very dependent on the amount of load added and the level of softness and thickness of the soil layer that is being burdened. The soil parameters used to estimate the size and duration of consolidation compression that occur in the field are the compression index (Cc) and the consolidation coefficient (Cv), respectively. These two parameters can be determined by conducting a consolidation test in the laboratory. The consolidation test that is commonly carried out in laboratories is the conventional method (Terzaghi, 1925), which is carried out by giving a load in stages and requires a long time and requires high costs. The consolidation test must be done very carefully because the degree of damage to the tested soil structure will affect the value of Cc and Cv, where this results in the magnitude and duration of consolidation that is thought to be incorrect. One way to overcome the above problem is to use a consolidation test with CRS method is by pressing the sample tested with a constant strain rate (constant rate of strain). Problems arise when a constant rate of strain (CRS) consolidation test is used for clay soils with a higher degree of plasticity

    From the results of previous studies it was found that the CRS consolidation test can provide accurate results if the soil plasticity level tested is not too high (Noor, 1993). Consolidation studies have also been carried out for organic clays with low organic content, which is a maximum of 16%. The results of the study show that there is a fairly good relationship between the srain rate chosen for the CRS method consolidation test and the organic content tested (Dlulqornain, 1995).

    What if the CRS method is used for soils with more than 16% organic content? What is the maximum percentage of clay organic content that can still be tested by the CRS method and how is the relationship between strain rate and organic content? For this reason, this study will examine the percentage of organic content that can still be tested using the CRS consolidation test and the strain rate chosen to determine the Cc and Cv consolidation parameters so that the results are consistent with the results of conventional methods.

    Test and analysis results show that the strain rate chosen in the test and organic content in the soil affect the testing period, the pore water stress formed on the sample (UB), and the effective stress formed, the Cv and Cc prices are also influenced by the strain rate and content organic in the soil. As a final conclusion of this study, the CRS method consolidation test when compared with the conventional method consolidation test provides a pretty good correlation ie strain rate 0.04% / minute for samples with 10% organic content, strain rate 0.02% / minute for samples with an organic content of 20%, a strain rate of 0.008% / minute for samples with organic content of 30% and 35%, a strain rate of 0.005% / minute for samples with an organic content of 40%, a strain rate of 0.002% / minute for soils with 45% organic content . The testing time for the same strain rate will increase with increasing organic content in the soil, as well as the same organic content, the testing time will also increase with the smaller strain rate