GEOSYNTHETICS: DRAINAGE COMPOSITE
Environment Friendly and Cost Effective
Alternative to Conventional Graded Filters
P
roviding proper drainage system conventional solutions respecting the hydraulic barrier and at the same time
for structures such as earth re- safety, technical and functional require- drain of excess water for area above the
taining structures, pavements, ments of structure. MacDrain are spe- drainage composite.
water front structures, canals etc is of cial type of geocomposites that enable
paramount importance. Locking of wa- rapid drainage of excess water while Functions of a MacDrain
ter inside the structure impose extra preventing soil particle migration. It is The main function of MacDrain is
water pressure and earth pressure due a geosynthetics product which is used to drain the water away from the struc-
to reduction in shear strength of soil. as an alternate to conventional gravel ture. The core part of MacDrain Which,
This reduces stability of structure and drainage layer behind earth retaining is made of polymer core networks as
can even lead to catastrophic failure. structures, buried structures like base- water carrier and the geotextile part
Traditionally gravel or aggregate layer ments and culverts, in trace garden, checks the passage of fine soil particles
in combination with sand is provided canal lining and dam applications etc. into drain and thus avoids the clogging
behind the earth retaining structures, MacDrain is 20 to 50% cheaper com- of drainage composite.
within earthen dams and as pavement pared to conventional graded filter. MacDrain serves the following
edge drains. However, the aggregates functions in a civil structure (as shown
used for filter and drainage layers is MacDrain – (Drainage Composite)
in Figure 2).
becoming scarce commodity in India Macdrain is a specifically designed
and an alternate material is essential to Geocomposite to meet the drainage - Drainage – Main / Primary function
replace the increasing need of aggre- and protection requirements in struc- - Filtration
gates for such infrastructure projects. turally demanding water draining ap- - Separation
Ban has been imposed in many states plications. MacDrain effectively elimi- - Erosion protection
on mining of precious natural resourc- nate hydrostatic pressure by collecting - Barrier (One side Geomembrane)
es / materials. and conveying groundwater to a drain
Conventional graded filters have lot pipe for discharge. Figure 1 shows a
of disadvantages like: Clogging of filter typical MacDrain which are made of
layer by fine soil particles, difficulty in lightweight three dimensional, high
quality construction (as there is a need compressive strength polymeric core Figure 2: Various function of drainage composite
to provide proper gradation of aggre- and nonwoven geotextile, provided on
gate / material depending upon the one side or both sides as per require- Drainage Composite behind Retaining
fill material) etc. With advancement of ments. Depending upon the application, wall and Bridge abuments
technology in the field of construction, drainage composite may also be pro-
‘Geosynthetics’ has become a simple vided with a Geomembrane or laminat- Drainage composite reduces the
and effective replacement to various ed geotextile on one side of it to act as pore water pressure and thus increas-
es the overall stability of earth retaining
structures. It is laid behind the wall fa-
cia as shown in Figure 3. At the bottom
end, it is connected to perforated PVC
pipe (Optional) of suitable diameter to
drain the water off. If in case there is the
conventional retaining wall system con-
sisting of the weep holes, the MacDrain
can be used for the dissipation of the
water that may be generated behind the
retaining wall.(Ref: Figure 3A).
Installation of MacDrain for Drainage
Applications
The general guideline for the suc-
cessful installation of MacDrain is men-
Figure 1 : Typical MacDrain Photograph tioned as follows:
GEOSYNTHETICS: DRAINAGE COMPOSITE
Figure 3: Drainage composite in Retaining wall Figure 3A : Drainage composite in Retaining wall
with weep holes
- Fixing the drainage composite to suspended horizontally from the top of - Place pipe surrounded material
structures structure. - Ensure no voids between side of
- Backfilling procedure the trench and the MacDrain which
- Horizontal drains Backfilling procedure: would result in uneven stress. This
- Other Considerations Here care should be taken that the precaution is important at the base
backfill material must not form a bar- near the crown of pipe.
Fixing the drainage composite to struc- - Care must be taken that the large
tures rier by becoming less permeable than
the soil being drained. Use the following stones are not allowed to damage
MacDrain must be held in position sequence: Backfilling should be done the MacDrain surface.
while backfilling is in progress. It can by proper compaction for the achieve- Seams:
be done by: nailing through wooden ment of the 95% compaction.
battens, or scaffold poles can be also It is done by using proper compactor. Edge seams shall be formed by
Figure 4: MacDrain installation behind Retaining wall
GEOSYNTHETICS: DRAINAGE COMPOSITE
Figure 5: Compaction in progress for MacDrain installation behind Retaining wall Figure 6: Attachment of Drainage Pipe with MacDrain
Conventional Method (Gravel
Solution With Macdrain Advantage Of MacDrain
Layer)
Graded filter by mixing range of
Geotextile layer at the base acts Better filter function be-
Filter soil particles sizes from gravel to
as filter cause of controlled quality
silt.
A much thicker drainage
drainage will be provided by a layer The drainage net will do the layer can be replaced
of granular material which is liable function of draining off the with a thin layer of
Drainage The to get clogged over period of time water with geotextile layer MacDrain performing
resulting in decrease in perfor- acting as a filter which will equal or better for the
mance not allow clogging to occur required drainage
function
Material quantity and quality tend
to differ along the length of the High level consistency in Better and consistent
Quality
wall due to construction sourcing quality and is maintained quality
and human error issues
Construction would be difficult
Ease of Construction is simple as it Faster and economical
especially laying the granular ma-
construction is very easy to lay the construction
terial in gradation behind wall
The cost of construction is high Reduction in excavation
Cost effective and faster
due to construction of several elimination of gravel bed,
construction. In general
elements for the drainage function perforated pipe network and
Cost 20 to 50% savings can be
and difficulty of construction as slurry seal and ease of
made by using MacDrain.
mentioned above laying MacDrain results in
lower cost of construction
Comparison of Gravel Vs Macdrain as a filter media
utilizing the flap of geotextile extending provide a sufficient overlap on all sides
fastened on both sides with non water
from the MacDrain edge and lapping to fasten.
soluble construction adhesive or any
over the top of the geotextile of the adja- According to MORTH minimum 600
other suitable method.
cent course. The geotextile flap shall be mm thick (Sec 3100, Cl no.3106.4 & Cl.
securely fastened to the adjacent fabric Repairs No. 2504.2.2) gravel is required behind
by means of a non watersoluble con- reinforced soil structure. Similarly,
struction adhesive or any other suitable If the MacDrain is damaged during 600mm thick (Appendix 6 Clause 2 IRC
method. Where vertical splices are nec- installation by tearing or puncturing, 78 :2000) drainage media is required
essary at the end of a drainage compos- the damaged section must be cut out behind abutment, wing walls and re-
ite roll or panel, a 200-mm continuous and replaced completely or repaired by turn walls (Mass gravity or RCC retain-
strip of geotextile may be placed, cen- placing a piece of MacDrain that is large ing walls). The smaller size aggregates
tered over the seam and continuously enough to cover the damaged area and shall be provided near to backfill soil
GEOSYNTHETICS: DRAINAGE COMPOSITE
face and larger size aggregates shall - Extremely effective solution com- vided intermittently in the conven-
be provided neat to wall face. pared to traditional stone drainage tional system is omitted by using
This kind of graded filter placement layer drainage composite and drainage
is very difficult to achieve. The gradation - Being light in weight, it is easy to pipe and hence provide good aes-
of backfill material may also vary from handle and install them quickly. thetic look to the wall.
stretch to stretch and it is very difficult - Made of PP and PE so durable and - The burden on natural resources
to consistently match the requirements chemical resistant for gravel/aggregate is also re-
unless very stringent quality control - High flow capacity as compared to duced.
measures are in place. conventional gravel drain - There is also a reduction in emis-
While MacDrain being factory man- sion of greenhouse gases due to
- Acts as drainage as well as protec-
ufactured product, are easy to install reduction in blasting and crushing
tion layer due to its high puncture
and suitable for wide range of soil gra- of rock aggregates.
resistance
dation. As the time passes, the fine soil
particles tend to clog the voids of gravel - Provides and maintains high flow
layer and thus the overall flow capacity paths for water and gases, there-
fore maintains soil stability For further details:
of gravel layer reduces drastically. But
the Macdrain have a filter geotextile lay- - Filtration properties are suitable for Maccaferri
er attached to its drainage core which most soil types 14th Floor, Vatika Professional
shall not allow the fine backfill parti- - Highly compressive strength core Point, Golf Course Ext. Road –
cles to clog the drainage net and thus - Robustness prevents puncturing Gurgaon , Haryana - 122 001
Telephone: +91 - 124 - 439 8400
ensures requires in-plane flow capacity and tearing during installation E-mail: info@in.maccaferri.com
and proper functioning. - Separates and protects structure Website : www.maccaferri.com/in
from fill material, and much more Regional Office:
Advantages of Drainage Composite
effective than conventional gravel Ahmedabad : +91- 79-4006 2958
Drainage composites provide effec- filter which are liable to clogging. Kolkata : +91- 33 - 4003 3210
Mumbai : +91-22 - 6164 2222
tive solution over conventional drainage - Since these are factory manufac- Pune : +91-20 - 4100 1900
layer. tured products so high quality can Chennai : +91- 44 - 3010 0000
Some of the inherent advantages of be assured Manufacturing Unit, Ranjangaon-
drainage composite are: - Weep holes that are generally pro- Pune: +91-2138 -393 000
