Critical Hydraulic Gradient And Hydrostatic Uplift

Question 1

This refers to the minimum slope or gradient required for a fluid to flow in an open channel without any portion of the flow becoming stagnant or backflow occuring

Answer 1

Critical Hydraulic Gradient

Question 2

The critical hydraulic gradient is defined by the _________ where particles start to outflow from soil samples.

Answer 2

Hydraulic Gradient

Question 3

This refers to the movement of water out of a geologic formation.

Answer 3

Outflow

Question 4

The determination of the critical hydraulic gradient of internal erosion is based on the occurrence of “_________” or other indicating phenomena of ___________.

Answer 4

Sand boil - seepage failure

Question 5

This is the slope of the water table or potentiometric surface, that is, the change in water level per unit of distance along the direction of maximum head decrease.

Answer 5

Hydraulic gradient abbreviated as i.

•The Hydraulic Gradient is the driving force that causes groundwater to move in the direction of maximum decreasing total head

• a dimensionless number, is the change in height(pressure) to length between any two points

Question 6

This is abbreviated as i and is the change in height(pressure) to the length between two points.

Answer 6

Hydraulic gradient

Given that: H=hydraulic head , L=Length

i= ha-hb/L
Or
i=∆h/L

Question 7

This geologic formation is due to the saturated loose sand when the sand is suddenly agitated.

Answer 7

Quicksand

When water in the sand cannot escape, this causes a sand boil, that is, the loss of strength of sand due to increase in pore pressure and cannot support weight.

Quicksand condition occurs in upward flow when the critical hydraulic gradient comes in the vicinity of unity.

Question 8

An upward pressure applied to a structure that has the potential to raise it relative to its surroundings.

Answer 8

Hydrostatic uplift or uplift pressure

Water pressure can overturn the whole structure and cause collapse during the early stages of construction.

It is the condition of greater pore water pressure than overburden pressure of the structure.

Question 9

Refers to the layers of sediments, rock, soil or structure that lie above a particular geological formation or deposit

Answer 9

Overburden

Question 10

The force exerted by the weight of the overlying rock, sediment, or soil or structure on a geological formation or structure beneath it

Answer 10

Overburden pressure