AS 1289.6.6.1:2020 pdf free.Methods of testing soils for engineering purposes Method 6.6.1: Soil strength and consolidation tests一Determination of the one-dimensional consolidation properties of a soil一Standard method.
Continue the readings until the slope of the characteristic linear secondary portion of the thickness versus log-of-time plot is obvious, see Clause 8.1 and Figure 1. For soils that have slow primary consolidation, loads shall act for the same periods of time and for a minimum of 24 h. In extreme cases, or where secondary consolidation is evaluated, loads will need to be applied for a longer period. Where the coefficient of secondary compression is to be determined, plot the time-settlement curve for the loading stage as the test progresses on a log time basis to ensure the rate of secondary compression can be defined. Then apply the next load increment.
When the thickness versus square-root-of-time method is used, the time intervals may be adjusted to times that have easily obtainable square roots, e.g. 0.09, 0.25, 0.49, 1 mm, 4 mm, and 9 mm, see Clause 8.1.3.
NOTE 4 Progressive plotting: Some advantage may be gained in determining when the next load increment may be applied by plotting the deformation versus square-root-of-time for the initial stages of consolidation in conjunction with a plot against log-of-time for the whole of the consolidation in the pressure increment. In some soils, 100 % consolidation can be achieved in less than 24 hrs and the next load increment may be applied prior to reaching 24 hrs.
On completion of the deflection readings, unload the specimen to the load increments as detailed in Steps 7(d) (1) and (ii). The unloading of the specimen shall occur for a minimum of 30 mm per stage. Lower pressure increments may result in the soils swelling, in which case the test shall be stopped.
On completion of the test, remove the specimen from the consolidation cell, record the mass of the ring and soil (mf). Extrude the soil out of the ring and cut the specimen with a trimming knife or break open for examination. Record the description of the cut or broken surfaces and the presence of layering, stones, calcareous matter and other irregularities. Determine the moisture content of the soil in accordance with AS 1289 2.1.1 and record as final moisture content.AS 1289.6.6.1 pdf download.