Determination of the liquid limit, plastic limit and plasticity index Lab Report

Determination of the liquid limit, plastic limit and plasticity index of a cohesive soil - Lab Report Example Data plot was taken from the results of the liquid limit test, where the x-coordinates or abscissas are the calculated moisture contents and the y-coordinates or ordinates are the penetration. The data points included in the plot are P1 (63.37, 14.13); P2 (66.26, 18.90); P3 (69.58, 19.45); and P4 (70.44, 22.15). The trend line or the best fit line was automatically fitted and the equation of the line was generated. From the figure, the equation of the best fit line is: y=0.9613x – 46.148. From step (10) of the laboratory procedure for the determination of the liquid limit, the theoretical value of moisture content which would produce a penetration of 20 mm is the liquid limit of the soil. Hence, when y in the above equation is substituted with 20, the value of the liquid limit (x) may be calculated algebraically as; y = 0.9613x – 46.148. 20 = 0.9163x – 46.148 0.9163 x = 20 + 46.148 x = 68.81 ? 69% - the liquid limit of the soil The value of the liquid limit obtai ned above is verified below by manual plotting. Manual Plot of Moisture Content vs. Penetration Plastic Limits Test No. 1 2 3 4 Container No.