Some Classical Terzaghi Primary Consolidation Differential Equation Mathematical Added Variabilities in Order to Get Better Field Monitoring Data Match Results

In this paper is illustrated a mathematical added variability of the classical Terzaghi primary consolidation equation (1923) considering independently as variables the Consolidation Coefficient Cv and as well the Height Hi of the consolidating Laboratory Consolidation Test soil sample in order to finally grasp the low permeability layer time behaviour. It is easy to show that, when the Cv variation is positive, each of these two added variabilities differentiations has as maximum a factor 2 related to the laboratory evaluated coefficient of consolidation, for a certain incremental load of reference in a Laboratory Consolidation Test. At this scope, it is analysed the overall behaviour of a typical clayey material, from the mineralogical point of view, namelyespecially either composed by lean clay with main kaolinite mineralogical content or fat namely with Illite mineralogical content or even very dilatant namely principally constituted by Montmorillonite. The Montmorillonitevariability with Cvis negative, and consequently the differentiation enhancement factor can become naught. As it is known so far, in normal conditions of a soft clay, a difference in Construction Values of the Coefficient of Consolidation is up to 23 times greater than laboratory evaluated results, and this according to the author’s experience, may be also mainly explained not starting from Laboratory Consolidation Test Data, but through a more general macroscopic behaviour of the soil underneath the newly loaded area, putting aside the case of temperature-induced changes. In conclusion, it is suggested how to model the analytical problem of the so modified Terzaghi Primary Consolidation differential equation in order to better manage the construction unknowns of the phenomenon.