GATE 2023 Soil Mechanics & Foundation Engineering Quiz 64

A Circular glass tube is filled with 18cm of sand of hydraulic conductivity 10^-5 m/s, and on top of that 20cm of sand of permeability that is larger by a factor 3 (see Fig.). The inner diameter of circular tube is 10cm. Compute the equivalent horizontal conductivity through the layered sample, if the head difference between the top and bottom layer is 18cm.

The relationship between the specific gravity of sand (G) and the hydraulic gradient (i) to initiate quick condition in the sand layer having porosity of 35% is

Consider the following data obtained in falling head permeability tests  regarding four soil samples A, B, C and  D:

Which one of the following soil samples has internally inconsistent data?

A homogenous earth dam 35 m high is built to store water for irrigation water requirement with a free board of 3m. A horizontal filter of 25 m length is provided at the base near the toe. The permeabilities of the soil in x and y directions are 3 × 10^–2 mm/s and 5 × 10^–2 mm/s respectively. A flow net constructed for the transformed section of the dam, consists of 6 flow channels and 14 head drops. The seepage loss per meter length (in liter/sec/m) of the dam is ____.

A foundation trench is to be excavated in a stratum of stiff clay, 8 m thick, underlain by a bed of sand. The ground water table is present at a depth of 2 m below the ground surface. The specific gravity of clay particles is 2.72 and void ratio of 0.72. If excavation is to be carried out safely to a depth of 6 m, by how much should the water table be lowered (in m) in the vicinity of the trench?