engineering recuitment GATE CE 2023-24 Test Series Soil Mechanics and Foundation Engineering Effective and Neutral Stress
A 15 m thick layer of clay lies over a gravel aquifer. The water table present in the gravel layer is under artesian pressure condition. Piezometer tubes introduced to the top of the gravel layer shows water level standing in the tubes 4 m above the top surface of the clay stratum. The clay layer is fully saturated with a water content of 50%. The other soil properties are G = 2.7.
With regards to the above data which of the following statements are correct?1
The maximum depth of excavation that can be carried out on the clay stratum without bottom heave is 4.53 m
2
The effective stress at the top of the gravel layer before any excavation is made is 67.2 kPa
3
The maximum depth of excavation that can be carried out on the clay stratum without bottom heave is 3.98 m
4
The porosity of the clay layer is 57.4%.