FORM 2
THE PATENTS ACT, 1970
PROVISIONAL SPECIFICATION
(See Section 10)
GEOTEXTILE SAND CONTAINER MATTRESSES
(GSCM) LINING FOR TEMPORARY RIVER
DIVERSION CHANNELS
Numbered as dated
INVENTORS:
a) RAJENDRA SHRIDHAR DESHPANDE
APPLICANT:
HINDUSTAN CONSTRUCTION COMPANY LIMITED
Hincon House,
Lai Bahadur Sastri Marg,
Vikhroli (West),
Mumbai-400 083,
Maharashtra,
INDIA

THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE NATURE OF THE INVENTION

GEO-TEXTILE SAND CONTAINER MATTRESSES (GSCM) LINING FOR TEMPORARY RIVER DIVERSION CHANNELS
A) TECHNICAL FIELD OF THE INVENTION
[0001] The present invention generally relates to the temporary river diversion method adopted during construction of hydraulic structures, like dam or barrage, across the river valley. More particularly it relates to the construction of geo-textile sand container mattress lining for river diversion channels in river valley projects.
B) BACKGROUND OF THE INVENTION
[0002] River diversion channel is an artificial channel that is used to divert the entire (or a part) of the flow in the river. River diversions are generally required for a range of civil engineering projects, including river valley projects, flood alleviation schemes, developments adjacent to a water course and scheme for new highways or highway widening. Some river diversions are temporary in order to permit construction work to be carried out and others are permanent.
[0003] In order to start the construction of dams or bridges over the rivers, the water need to be drained out first, to expose the river bed. Generally


during the dam or bridge constructions, first the temporary dams, termed as cofferdams are constructed to isolate and divert the river flow.
[0004] Rivers are generally required to be diverted so as to facilitate the construction of hydraulic structures, like dam or barrage, across the river valley in the construction of river valley projects. Temporary river diversion work is a very important work in most of the river valley projects. There are two main types of river diversion. First is by diversion through tunnels and second by diversion through channel. Out of these two methods, diversion through tunnels is resorted to in steep valleys where geographical features of the project site are such that the diversion through channel is not possible or uneconomical. In most of the projects, diversion through channel is the easiest and most economical way of river diversion.
[0005] Geotextiles are the strong and flexible fabrics made from polypropylene for use in several applications, including geotechnical and hydraulic applications. They possess good mechanical properties like tensile strength, elongation, perforation resistance, and good hydraulic properties like small opening size and high permeability. Geotextiles can be woven or non-woven, varying in thickness, with or without ultra violet protection. The geotextile is used in numerous applications including soil reinforcement, separation and drainage layers in roads sub-grade construction, drainage media in agriculture, filters and infiltration barriers in hydraulic structures.
[0006] Usually the diversion channels are designed and constructed for a functional period of one to three years depending upon the type and size of the


project. These channels are required to carry monsoon and non-monsoon river discharge safely without hampering or endangering construction activity. The diversion channels are invariably provided with linings on the sides and the bottom to withstand scouring and erosion due to very high flows through the restricted channel.
[0007] The construction of diversion channels is usually carried out in non-monsoon lean flow period. A very large quantity of excavation is required to be carried out which consumes major part of available time leaving hardly less than two months period for execution of lining work. Also, arrangements are required to be made to transport and dump the excavated earth at a designated place, which could be some distance away from the site of the diversion channel, where the excavation is carried out.
[0008] Traditional diversion channels are lined with boulders, 600 to 800 mm thick, in concrete ribs. Well graded sand-gravel filter of thickness varying from 300 to 600 mm is provided below the boulders. Availability of large quantity of boulders and sand, their transportation to the site and stacking in a very narrow time frame involves unnecessary delays and higher costs. Hence the traditional lining designs results in several drawbacks including nonavailability of boulders of requisite size in huge quantity, higher machinery cost, prone to damages due to hydro-dynamic forces.
[0009] Considering above mentioned demerits, there is a need for more economical, speedy and reliable method of lining that provides an effective lining for temporary river diversion channels.


C) OBJECTIVES OF THE INVENTION
[0010] The primary objective of the invention is to develop a geo-textile sand container mattresses lining for temporary river diversion channels.
[0011] Yet another objective of the invention is to provide speedy and easy construction of river diversion channel using locally available material which is reliable, economical and results in better performance.
[0012] Yet another objective of the invention is to use geo-textile as an excellent filter media below the mattress.
[0013] Yet another objective of the invention is to design a geo-textile filter based on the surrounding soil properties and the hydraulic parameters.
[0014] Yet another objective of the invention is to provide galvanized iron wire crates of desired thickness for resisting hydrodynamic forces and to avoid erosion due to abrasive material in the flow.
[0015] Yet another objective of the invention is to provide a toe wall to provide stability to sloping sides of the diversion channel.


D) SUMMARY OF THE INVENTION
[0016] The present invention addresses and recognizes the foregoing disadvantages, and others, of prior art constructions and methods. Accordingly the objective of the present invention is to construct an improved river bed material (or sand) filled geo-textile mattress lining for temporary river diversion channel.
[0017] The construction methodology includes filling the pre-stitched geo-textile bags with the river bed material and then stitching their (open) mouths to close the bags. The filling and stitching of bags activity is carried out in parallel with the laying of the geo-textile filter as the bottom layer of the already excavated (diversion) channel. The design of bags is based on the hydraulic parameters. Generally the bags provided in the bed lining are made bigger in size than those provided in side lining. Whereas woven geo-textiles are used to make these bags, unwoven geo-textiles are proposed to be used as a filter below the mattresses, because of their excellent filter properties. The latter geo-textile layer is laid on the bed and sides of the excavated channel, and acts as a filter below GSCM lining.
[0018] The requirements for the geo-textile to be used as filter and that used for bags is decided on the basis of hydraulic design requirements, which, in turn, depend on many factors like maximum discharge, depth of flow, velocity, size of rolling boulders, soil properties, etc. Geo-textile filter is to be provided as a continuous media by proper stitching. Hand held industrial


stitching machines can be used for in-situ stitching. The geo-textile filter design is based on the surrounding soil properties and the hydraulic parameters related to the channel flow. Usually the non-woven geo-textile is more effective as a filter.
[0019] The next step in the construction is to place galvanized iron wire crates on the laid geo-textile. Geo-textile bags filled with river bed material are placed inside the crates. The crate lid is closed and tied with galvanized iron lacing wire. Another crate is placed adjoining the previous crate and the process is repeated to form a continuous chain of crates. Adjoining wire crates and top lids of crates are tied together by galvanized iron lacing wire. The thickness of wire crates, mesh opening size and gauge of wire are designed for resisting various forces like hydrodynamic forces, erosion due to abrasive material in the flow, impact due to rolling boulders, etc.
[0020] Depending upon design requirements wire crates can also be placed in multiple layers. If necessary, geo-textile with galvanized iron wire mesh can also be provided on top of wire crates as an additional protective layer. The provision of toe wall is made so as to add to the stability of sloping sides of the diversion channel. Depending upon the soil condition, high yield strength deformed steel anchors of adequate diameter and length will be provided to check against the movement of crates due to severe hydraulic conditions.


E) BRIEF DESCRIPTION OF THE DRAWINGS
[0021] The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiment and the accompanying drawings in which
[0022] FIG. 1 illustrates a schematic diagram showing the geo-textile sand container mattress lining according to one embodiment of the invention.
F) DETAILED DESCRIPTION OF THE INVENTION
[0023] The present invention relates to the construction of the geo-textile sand container mattress lining for the temporary river diversion channel. The diversion techniques are used during construction of hydraulic structures, like dam or barrage across a river. The various stages under which the construction of the geotextile sand container mattresses (GSCM) lining is carried out for river diversion channels are listed as follows. Initially the pre-stitched geotextile bags are filled with river bed material and their open mouths are stitched. The filling and stitching of bags activities are done parallel to layout of geotextile filter. Geotextiles are the strong and flexible fabrics made from polypropylene for use in geotechnical and hydraulic applications. They possess good mechanical properties like tensile strength, elongation, perforation resistance, and good hydraulic properties like small opening size and high


permeability. Geo-textiles can be woven or non-woven, varying in thickness, with or without ultra violet protection. Generally the non-woven geo-textile will be more effective. The geo-textile is used in numerous applications including soil reinforcement, separation and drainage layers in roads sub grade construction, drainage media in agriculture, filters and infiltration barriers in hydraulic structures.
[0024] Now the Geo-textile is laid on the excavated channel bed and sides. It acts as a filter below GSCM lining. The design of bags is based on the hydraulic parameters. Generally, bags provided in the bed lining are bigger in size than those provided in side lining. Geo-textile is the basic material used in GSCM because of its excellent technical properties. It acts as an excellent filter media and hence can be used as a filter below the mattress. The main advantage behind this is to obtain uniform construction and to obtain required thickness of the filter layer. More over the geo-textiles are widely available and inexpensive. The requirements for the geo-textile to be used as filter and that used for bags is decided on the basis of hydraulic design requirements, which, in turn, depend on many factors like maximum discharge, depth of flow, velocity, rolling boulders, soil properties, etc. Geo-textile filter is provided as a continuous media by proper stitching. Hand held industrial stitching machines are used for in-situ stitching. The geo-textile filter design is based on the surrounding soil properties and the hydraulic parameters related to the channel flow. Usually the non-woven geo-textile will be more preferable since they are more durable.


[0025] The next step in the construction is to place galvanized iron wire crates on the laid geo-textile. Geo-textile bags filled with river bed material are placed inside the crates. The crate lid is closed and tied with mild steel lacing wire. Another crate is placed adjoining the previous crate and the process is repeated. Adjoining wire crates and top lids of crates will be tied together by galvanized iron lacing wire. The thickness of wire crates, mesh opening size and gauge of wire are designed for resisting various forces like hydrodynamic forces, erosion due to abrasive material in the flow, impact due to rolling boulders, etc.
[0026] Depending upon design requirements wire crates can also be placed in multiple layers. If necessary geo-textile with galvanized iron wire mesh can also be provided on top of wire crates as an additional protective layer. The provision of toe wall shall be made so as to add to the stability of sloping sides of the diversion channel. Depending upon the soil condition, high yield strength deformed steel anchors of adequate diameter and length will be provided to check against the movement of crates due to severe hydraulic conditions.
[0027] FIG. 1 shows the schematic diagram of the Geo-textile sand container mattress lining. It includes an inner mild steel wire layer, geo-textile sand bag, an outer geo-textile filter and a toe wall. The geo-textile sand bags are laid between the wire crates and the geo-textile filter. The geo-textile sand bags which are pre-stitched are filled with the river bed material and their open mouths are stitched. The galvanized iron crates filled with these geo-textile bags are laid on the excavated channel bed and sides. The geo-textile also acts as a


filter below the mattress lining. The design of these geo-textile bags are based on the hydraulic parameters. The filter design, as shown in the figure is based on the surrounding soil properties and hydraulic parameters. The wire crates are designed for resisting various forces like hydrodynamic forces, erosion due to abrasive material in the flow, impact due to rolling boulders. Geo-textile bags filled with river bed materials are placed inside the crates. The crate lid is closed and tied with mild steel lacing wire. Another crate is placed adjoining the previous crate and the process will be repeated. Adjoining wire crates and top lids of crates will be tied together by galvanized lacing wire. Depending upon the requirements wire crates are also be placed in multiple layers. The toe wall is constructed to provide stability to the sloping sides of the diversion channel.
G) ABSTRACT
[0028] The embodiments of the present invention provide a geo-textile sand container mattress lining and its construction method. The geo-textile bags filled with river bed material are provided in the galvanized iron wire crates arranged on the geo-textile filter arranged at the sides and the bed of the river diversion channel. The galvanized iron lacing wires are used to tie the wire crates provided on the filter bed with each other.
The detailed scope of the monopoly claimed for the invention shall be ascertained and provided at the time of filing of the complete specification.
Dated this the 27TH day of September 2007


Rakesh Prabhu,
Patent Agent, ALMT Legal,
No.2, Lavelle Road, Bangalore-560 001, INDIA
To,
The Controller of Patents,
The Patent office,
At Mumbai.