ASTM D2435/D2435M-11 (R2020) PDF Download

ASTM D2435/D2435M-11 (R2020) is a standard that provides test methods for determining the one-dimensional consolidation properties of soils using incremental loading. The test results obtained from this standard are useful in estimating the settlement of structures or earthfills and evaluating their performance in engineering design.

The standard emphasizes the importance of minimizing sample disturbance to obtain accurate test results. Careful selection and preparation of test specimens are required to reduce the potential effects of disturbance. It is noted that the precision of the test method depends on the competence of the personnel conducting the test and the suitability of the equipment and facilities used.

The standard allows for different loading schedules to model specific field conditions or meet special requirements. The traditional loading procedure involves doubling the axial stress for each increment, but other loading schedules may be used based on the characteristics of the soil being tested.

Two alternative procedures are provided in the standard: Test Method A and Test Method B. Test Method A entails constant load increment durations, while Test Method B requires time-deformation readings on all load increments. The choice of method depends on the specific requirements of the project.

The standard specifies the assumptions and evaluation techniques based on conventional consolidation theory to compute the coefficient of consolidation. These assumptions include the soil being saturated and having homogeneous properties, vertical flow of pore water, negligible compressibility of soil particles and pore water compared to the soil skeleton, linear stress-strain relationship, constant ratio of soil permeability to compressibility over the load increment, and application of Darcy's law for flow through porous media.

It should be noted that compliance with the standard does not assure reliable testing, as reliable testing depends on various factors. The standard provides guidelines for conducting the test but acknowledges that alternative techniques may be used with agreement from the requesting agency, as long as they are still in conformance with the standard.