Coefficient of Consolidation by the Slope Method

The slope method explicitly relates the coefficient of consolidation c(v) to the slope of the initial linear segment of the observed delta(t)-root t curve and to the end of primary settlement delta(p). The slope method utilizes the same graphical construction as the Taylor method but eliminates the use of the factor 1.15 that usually leads to lower delta(p) and higher c(v) as compared to the Casagrande method and pore water pressure measurements. Instead, the point at which the delta(t)-vt curve deviates from the linear portion (at U of about 50%) is considered for estimating delta(p). Oedometer test results on four soils show that the c(v) values of the slope and Casagrande methods are comparable but lower than those of the Taylor method.