Stress induced time dependent behavior of clayey soils

Abstract

It is shown that time compression curve obtained from one-dimensional consolidation curve in the laboratory may include six phases. These are initial compression, first primary compression, transition from first primary compression to second primary compression, second primary compression, and transition from second primary compression to creep and lastly creep. This paper attempts to identify the quantitative beginnings and characteristics of these phases. A mathematical characteristic of all the soils that follow primary consolidation as per Terzaghi's one dimensional consolidation theory is derived. It is known as the constant of primary consolidation. It is used to study the beginning of secondary consolidation and its effects on primary consolidation. Another characteristic of soils for creep and total absence of primary compression is derived. Methods are suggested for the determination of coefficients of Primary and Secondary consolidations and the compression index.

Theoretical Equations of Vertical and Radial Consolidation by Equating Degrees of Consolidation by Settlement Analysis and Dissipation of Pore Pressure

“…It was shown that difference in c v values was insignificant. Tewatia (1998), Tewatia et al (2007,) and Tewatia (2010) divided Terzaghi's Eq. 2 into 3 parts in 40:20:40 ratio.…”

Principle of Super Position of Rate of Settlement in 2D and 3D Consolidations

“…10 and 13, it can be shown that it leads to the following experimental Eq. 32 (Tewatia 2010;Tewatia et al 2012Tewatia et al , 2013 …”

“…After 60 % consolidation vertical consolidation and radial consolidation, both are linear on d-dd/dt plot (Tewatia 1998(Tewatia , 2010Tewatia et al 2007Tewatia et al , 2012Tewatia et al , 2013. Here, the lines OA and OB are the lines joining points O and A, and O and B.…”

“…Straight line in lower portion is extrapolated to meet d axis at d 100 (where dd/dt = 0). The vertical difference between the curve and straight line, parallel to d axis, at any point, is secondary compression at that point (Tewatia 1998(Tewatia , 2010Tewatia et al 2007) 10 Leo (2004) Type Solution of General 3D Consolidation Eq. 1 in Cartesian Co-ordinates…”

“…Same is the principle when initial and primary compression occur together. Using this principle, primary and secondary consolidations were quantitatively isolated and mathematical/graphical conditions were suggested for pure primary and pure secondary consolidations (Tewatia 1998;Tewatia and Bose 2006;Tewatia et al 2007). Similar principle is applied in this paper for solving the theoretical and experimental problems of 2D and 3D consolidations.…”