A homogeneous earth dam has a maximum water head difference of 15 m between the upstream and downstream sides. A flownet was drawn with the number of potential drops as 10 and the average length of the element as 3 m. Specific gravity of the soil is 2.65. For a factor of safety of 2.0 against piping failure, void ratio of the soil is __________ (rounded off to 2 decimal places).
The in-situ percentage of voids of a sand deposit is 50%. The maximum and minimum densities of sand determined from the laboratory tests are 1.8 g/cm3 and 1.3 g/cm3, respectively. Assume the specific gravity of sand as 2.7.
The relative density index of the in-situ sand is ______________ (rounded off to 2 decimal places).
A drained triaxial test was conducted on a saturated sand specimen using a stress-path triaxial testing system. The specimen failed when the axial stress reached a value of 100 kN/m2 from an initial confining pressure of 300 kN/m2.
The angle of shearing plane (in degrees) with respect to horizontal is ______________ (rounded off to the nearest integer).
A storm with a recorded precipitation of 11.0 cm, as shown in the table, produced a direct run-off of 6.0 cm.
| Time from start (hours) | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
|---|---|---|---|---|---|---|---|---|
| Recorded cumulative precipitation (cm) | 0.5 | 1.5 | 3.1 | 5.5 | 7.3 | 8.9 | 10.2 | 11.0 |
The Ø-index of this storm is ______________ cm/hr (rounded off to 2 decimal places).