particular specifications (road works) - CIDCO Maharashtra Ltd.

CIDCO OF MAHARASHTRA LTD
C.A.No.01/CIDCO/SE(KHR)/EE(KHR-I)/2010–11 Pg. No. 399
8.2.3 Requirement of filter material:
NOTE:
1. D15 of filter/D15
of Base material
2. D15 of filter/D85
of base material
– 5 to 40, provided that the filter
dose not contain more than 5% of
material filter than 0.075mm.
- 5 or less
3. The grain-size curve of the filter should be roughly parallel to
that of the base material.
Filter may not be required if embankment consists of CH or CH soils
with liquid limit grater than 30, resistant to surface erosion. If a layer of
material is used in this case as bedding for pitching, it shall be well
graded and its D85 size shall be at least twice the maximum void size
in the pitching.
1. In the forgoing, D15 means the size of the sieve that allows 15%
by weight of the filter material to pass through it, and similar is
the meaning of D 85.
2. If more than one filter layer is required, the same requirement as
given above shall be followed.
3. The finer filter shall be considered as the base material for
selection of gradation of the coarser filter.
4. The filter material shall be suitable complete to a firm condition.
8.2.4 Construction Operations:
Before laying the pitching the sides of banks shall be trimmed to the
required slope and profiles put up by means of line and page at