Question

The profile of a weir on the permeable foundation is shown in figure I and an elementary profile 'upstream pile only case' according to Khosla's theory is shown in figure II. The uplift pressure heads at key points Q, R, and S are 3.14 m, 2.75 m, and 0 m, respectively (refer figure II).


What is the uplift pressure head at point P downstream of the weir (junction of floor and pile as shown in the figure I)?

• A. 2.75 m
• B. 1.25 m
• C. 0.8 m
• D. Data not sufficient

Answer 1

The correct option is B 1.25 m



As the pile on d/s is of same length of u/s hence,

${\varphi }_P=4-{\varphi }_R$

${\varphi }_P=4-2.75$

${\varphi }_P=1.25m$