Question

i) Draw (using graph paper) a flow net for the sheet piling configuration whose cross section is illustrated in Figure Q3. 

ii) Calculate the water flow under the pile per metre length of piling assuming the soil to have a permeability k = 1.3 × 10-4 m/s.

Answer 1

Drawing flownet is not a big task.it is just a way to show pattern of how flow is taking place and how drop in potential of flow taking place.

So ,for drawing flownet we have to just keep a statement in mind and that statement is :- equipotential lines and flowlines are perpendicular to each other at each point..... .

Now see the attachment

(Pg-y off low het is graphical representation of path taken by the water particles. * Flow lines and eQui potential lines are Ourthogonal [ perpendicular to each other] NOTE:- * Flownet is drawn by Firstly drawing flow lines (flow lines can be of any number upon you) * after drlwing flow lines, Make Equipotential lines perpendichlar to Flow Lines PORANGE - EQUIPOT 13m Flow) depending ) y LI NE'S LINES BLUE LINES STREAM LINE 6 8.6 m

PG-2] こ (H) Head Loss = 3m Nu = No. of Equipotential drops = No. of Equipot. Lines - 1 8-1 = 67 drops Nf = Number of flow channels flow lines - 1 - 4-1 = 3 How channels Q = Discharge pea meter length = KHANA Nd K=1.3 X 10 m/s where 2 -4 El•3X10X3X3 7 = 1067X10-4 m3/s/m