Triaxial undrained test - Essay Example

In turn the values from this graph as well as the resulting Excel sheets were used to determine the maximum deviator stress for each sample under investigation. The maximum deviator stress and the relevant cell pressure for all three samples are shown in the table below. The calculation was carried out relying on the test equipment that produced values for measured force using a load cell calibration constant. The calibration constants for all three samples are presented in the table below. The highest value of corrected stress was taken from this graph and the tables and was plotted in the form of Mohr’s circles.

Once the Mohr’s circles were drawn, they were connected together using a common tangent. This tangent is critical to the calculations required as the y-intercept represents cohesion while the inverse of the gradient of the tangent represents the internal friction angle of the soil. The plot of Mohr’s circles and the resulting graph is shown below. Using the plot shown above the y-intercept and the angle that the tangent made with the horizontal were calculated. The y-intercept was 306.68 while the angle of the tangent with the horizontal was 3.

62 degrees. Once this was found, it was time to find out the void ratio and the degree of saturation. This was done with the help of the taken weights (which are shown in the table below for all samples) and with the use of the formulas shown after them. The results obtained from the Mohr plot indicate that the soil has a high cohesion (306.68 kN/m2) but a small angle of friction (15.81 degrees). In turn this can be used to surmise that the soil sample under investigation has relatively good shearing properties although it is prone to failure if the angle of repose is increased by a large amount.

The other thing to take note of is whether the soil sample under investigation has been packed