An approach for the determination of the preconsolidation pressure in sensitive clays

Abstract

The present methods for the determination of the preconsolidation pressure of clays are time consuming and expensive. A new method is proposed in which the clay is loaded in a "one-stage loading" to an axial stress in excess of the estimated preconsolidation pressure. The preconsolidation pressure is determined from the observation of the pore pressure dissipation within a few hours. The theoretical basis of this method is also used to discuss the method of interpreting constant rate of strain and constant gradient oedometer tests.

Effects of Friction and Thickness on Long-Term Consolidation Behavior of Osaka Bay Clays

“…Therefore, there were other causes of the characterized pore pressure dissipation pattern. Leroueil et al (1980) obtained a similar and clearer pore pressure dissipation pattern for sensitive eastern Canada clay with a signiˆcantly developed structure. In Fig.…”

“…Depth proˆles of consolidation parameters mv, k, and cv evaluated for each specimen element their explanation for this behavior, the sudden dissipation at the beginning corresponded to a larger coe‹cient of consolidation in the overconsolidation range and the consequent slow dissipation corresponded to a smaller coe‹cient of consolidation in the normal consolidation range. Because Ma12 had a high water content with a higher developed structure, the explanation of the behavior can be the same as that of Leroueil et al (1980).…”

Preconsolidation pressure of Champlain clays. Part II. Laboratory determination

“…According to Leroueil et al (1980), the curve showing the vertical effective stress at the base of the specimen plotted against the logarithm of time develops a step at an effective stress equal to the preconsolidation pressure. In such tests, o; is reached in a very short time and is associated with very high strain rates.…”

“…197 1): where u, = total vertical applied stress, uo = applied back pressure, and ub = pore pressure measured at the base of the specimen. Leroueil et al (1980) have pointed out the limitations of [2] when a(, is close to a; in sensitive clays. On the other hand the measured values of ub at u; were such that the error on a; could generally be considered negligible.…”

“…strain oedometer test (Hamilton and Crawford 1959;Smith and Wahls 1969;Wissa et al 1971;Sallfors 1975); (b) the controlled gradient oedometer test (Lowe et a/. 1969); (c) the single stage loading oedometer test (Leroueil et al 1980); (d) the anisotropic triaxial consolidation test (Tavenas and Leroueil 1977).…”