Evaluation of True C_u, and Instantaneous C_u, and Isolation of Secondary Consolidation
Tewatia SK
(Received 9 July 1996; accepted 5 January 1998)

Abstract
It is shown that the presence of a distinct straight line in the initial portion of settlement versus the square root of time plot indicates that soil follows theoretical behavior and that there is no initial and secondary compression in the straight line portion. If the coefficient of consolidation, c_u, is determined using the data of only this portion, it can he regarded as the true c_u. Secondary consolidation essentially starts after 60% consolidation and runs superposed over the primary consolidation. Its effect is to gradually decrease c_u so that at every instant of time it is a new Terzaghian soil with a new c_u and other consolidation parameters. Characteristics of linear and semi-log plots of U versus U, where U is the degree of consolidation and U is the theoretical velocity, are used for determining true c_u and instantaneous c_u, and for isolation of secondary consolidation from the experimental consolidation curve.

Keywords:
coefficients, consolidation, drainage, laboratory test, load, settlement, slope, velocity

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Author Tewatia SK Title Evaluation of True C_u, and Instantaneous C_u, and Isolation of Secondary Consolidation Symposium , Committee on