ASTM D4186/D4186M-20e1 PDF Download

ASTM D4186/D4186M-20e1 is a standard test method for determining the one-dimensional consolidation properties of saturated cohesive soils using controlled-strain loading. The purpose of this test method is to provide information about the magnitude of compression and rate-of-consolidation of soil, which is essential in the design of earth structures. The results obtained from this test method can be used to analyze settlements, rates of settlement due to dissipation of excess pore-water pressure, and rates of fluid transport.

The test method considers several factors such as strain rate effects, temperature effects, saturation effects, and test interpretation assumptions. Strain rates during consolidation processes in the field are generally slower than laboratory strain rates, so it is not practical to replicate field strain rates in the laboratory. Temperature affects parameters such as hydraulic conductivity and coefficient of consolidation, but corrections for specific field conditions are beyond the scope of this test method. The test method requires the soil to be saturated, and it cannot be used for partially saturated soils.

The test method utilizes steady state equations based on certain assumptions, including the assumption of soil homogeneity and negligible compressibility of soil particles and water. The equations used in this test method are applicable to steady state conditions. Different equations are available for linear and nonlinear soil models. The test method provides the calculation of total and effective axial stresses, axial strain, coefficient of consolidation, and hydraulic conductivity.

It should be noted that the results of this test method are dependent on the competence of the personnel performing the test and the suitability of the equipment and facilities. Compliance with the specified practices does not guarantee reliable results, as many factors can influence the accuracy of the test results.