Taylor’s Square Root of Time Fitting Method - Determination of Coefficient of Consolidation of Soil, | Soil Mechanics Notes- Agricultural Engineering PDF Download

Taylor’s Square Root of Time Fitting Method

From the oedometer test (explained in Lesson 23) the dial reading (settlement) corresponding to a particular time is measured.  From the measured data, dial reading vs \[\sqrt {Time}\] graph can be drawn (as shown in Figure 24.1). A straight line can be drawn passing through the points on initial straight portion of the curve (as shown in Figure 24.1). The intersection point between the straight line and the dial reading axis is denoted as R₀ which is corrected zero reading i.e U = 0%.  Starting from R₀, draw another straight line such that its abscissa is 1.15 times the abscissa of first straight line. The intersection point between the second straight line and experimental curve represents theR₉₀ and corresponding \[\sqrt {{t_{90}}}\] is determined. Thus, the time required (t₉₀) for 90% consolidation is calculated. The Coefficient of consolidation (c_v) is determined as:

\[{c_v}={{{T_v}{H^2}} \over t}\]                    (24.1)

where H is the thickness of the soil sample, t is required time. T_v is the vertical time factor and can be determine as:

\[{T_v}=\left({{\pi\over 4}}\right){U^2}\quad \quad if\;U \le 60\% \]   %                (24.2)

\[{T_v}=1.781 - 0.933{\log _{10}}(100 - U)\quad \quad if\;U > 60\% \]   %               (24.3)

Fig. 24.1. Taylor’s Square Root of Time Fitting Method.