Construction of well foundation
Work is done during non-monsoon months of the year
Islolate the area by making bund around it so that river water flows
beyond e isthlnda. Sheet piling is also resorted where bed is
deep
Low height Sand island is created as platform over which cutting edge of steel
for well curb is placed and well curb is cast with some steining height
(may be 1.5 to 3.0m)
Kentelage (load ) is applied through platform at top of steining, cast so far,
to sink the steining and simultaneously dredging of material from inside is resorted.
Keep Casting steining and applying kentelage to sink it.A minium 48 Hrs curing time
is must for steining after its casting for it to be ready for sinking.
Initially the sinking will be faster and inside dredging is easy due to soft top strata
Once steining get sunk deeper, there is enough friction from sides.Dredging from inside will
need effort for sinking it ( before loading it) thru trained divers(with oxygen mask) who go
below and dredge at bottom of steining since river water seeps into well
The process goes on for one or more seasons depending upon depth of sinking.
The sinking process is slow and time taking.Half constructed wells
have to see the flash floods of river when islands and bunds wash away
during monsoon.
Once final level is achieved, well is plugged at bottom with rich concrete as per
drg and specifications.This is bottom plug.
Well upto nearly mid-height is filled with sand(or excavated material free
from organic matter) and again plugged with rich concrete
acting as intermediate plug.
From intermediate plug upto well cap soffit level , the well is filled with
sand/exc material and well cap is cast.