Title of Invention	EXCAVATION METHOD FOR TUNNELS AND VERTICAL SHAFTS IN ROCK, USING WATER JET CUTTING AND SYSTEM FOR SUCH EXCAVATION OF TUNNELS
Abstract	Two methods for the excavation of tunnels, shafts and rocks with high-pressure water jet cutting technology are invented. The first method comprises, to make first a groove at the rock cutting face bottom. A vertical nozzle is located through said groove and a horizontal nozzle is placed at a predetermined distance. Verticar nozzle, starts cutting ahead followed by horizontal nozzle. While the horizontal nozzle cuts, the rock is weakened and broken down by its weight. The second method alternatively comprises to make cutting in grid pattern with plurality of nozzles simultaneously resulting in pre-weakening of the rock. The pre-weakened rock is knocked down by simple mechanical means. In both methods the nozzle sizes are between 1.1mm to 1.8 mm but one or two nozzles are used simultaneously. It comprise of high-pressure pump, nozzle-holding arm, cutter head, nozzle and la~ces. The motions are controlled by CNC.

Title of Invention

EXCAVATION METHOD FOR TUNNELS AND VERTICAL SHAFTS IN ROCK, USING WATER JET CUTTING AND SYSTEM FOR SUCH EXCAVATION OF TUNNELS

Abstract

Two methods for the excavation of tunnels, shafts and rocks with high-pressure water jet cutting technology are invented. The first method comprises, to make first a groove at the rock cutting face bottom. A vertical nozzle is located through said groove and a horizontal nozzle is placed at a predetermined distance. Verticar nozzle, starts cutting ahead followed by horizontal nozzle. While the horizontal nozzle cuts, the rock is weakened and broken down by its weight. The second method alternatively comprises to make cutting in grid pattern with plurality of nozzles simultaneously resulting in pre-weakening of the rock. The pre-weakened rock is knocked down by simple mechanical means. In both methods the nozzle sizes are between 1.1mm to 1.8 mm but one or two nozzles are used simultaneously. It comprise of high-pressure pump, nozzle-holding arm, cutter head, nozzle and la~ces. The motions are controlled by CNC.

Full Text	This invention relates to excavation method for tunnels and vertical shafts in rock, in Hydroelectric Power Projects. More particularly this invention relates to excavation method for tunnels and vertical shafts in rocks, using water jet cutting and system for excavation of tunnels. Generally the hydro electric power projects involves the construction of Dam to impound the water, intake structure, power house, Head race tunnels to convey the water from the intake to the power house and then tunnels. Normally the shape of the tunnel is D shape or Horseshoe shape and the diameter varies from 7.0 Meters to 10.0 Meters based on the design capacity of the project. The length of the tunnel will be around a kilometer or more, based on the location of the river water intake and the powerhouse. The number of the tunnels and shafts is based on the capacity of the project. Tunnels are typically constructed either using the drill and blast method or by using tunnel boring machines. The tunneling operation is a repetitive process wherein the same activities are repeated in each successive cycle. Also, it is common practice to open up more than one face of a tunnel for excavation, so that the project can be expedited. Basis of the invention The applicant had the necessity of executing a 2000 MW Hydro Electric project in the North Eastern region, wherein 8 numbers of 9.5 meter diameter horseshoe shaped Head Race Tunnels (HRT), having lengths varying from 630 mts. To 1145mts. And 8 numbers of 8.0 meter diameter vertical shafts and adit tunnels had to be excavated in the rock. Due to the nature of the rock and seismic severity of the site, tunneling activity have to be done by non-explosive methods only, which culminated in the application of water jet cutting technology in the project leading to the development of this novel excavation method and system for excavation of tunnels. Prior art Drilling or cutting high-strength rock is earlier achieved using heavy, expensive and often inflexible drills and machines to deliver the large forces needed for breakage. Then system utilising oscillating disc cutting (ODC), has been first tested cutting high-strength granite (greater than 250 MPa UCS) at relatively high speeds, using a lightweight support structure. In contrast to conventional disc cutters, which require high compressive loads to fracture rock, the ODC system exploited the tensile weakness of rock through 'undercutting1. This allowed strong rock to be cut using lower forces. As a means of excavating hard rock, the ODC system promises a safer, cleaner and cheaper alternative to drilling and blasting. There are likely to be multiple applications in mining and civil engineering for the small, highly maneuverable, continuous excavation machines. It was also investigated that the effectiveness of improved tool materials, in conjunction with cutter assistance methods such as water jets. Water-jet assisted cutting reduces the forces acting on tools and thus, their susceptibility to wear, by using high-velocity water jets to cool the tool during excavation. Water-jet-assisted cutting of minerals is quite recent technology. Production type water-jet-assisted road headers have been in use in underground mines for quite some time. Also, in North America, Europe and Japan, companies are developing water jet assisted drilling equipment. Most of the aforementioned cutting and drilling equipment are in the prototype and pre-production stages. Every equipment manufacturer uses different components for its water-jetting system. It is expected that water-jet-assisted cutting and drilling technology will be widely used by the mining and construction industries within this decade. It has been known for some time that water jets of moderate pressure (below 100 MPa) are effective in assisting drag bit cutting of rocks, provided that they are directed onto a rock region close to the tool tip, and the water jets lead to a substantial reduction of the tool forces. The actual physical process underlying this effect is still poorly understood, so that the technique has not yet been optimized. There are two basic limitations to a generalized application of mechanical rock excavation techniques. One is rock hardness and abrasiveness, the other is resulting inflexibility of machines designed to excavate hard rocks. Relatively light and flexible machines, like Road headers, are. used in soft rock formations. Their drag bit cutter tools, however, are very sensitive to rock hardness and abrasiveness. In hard rock formations, it is necessary to use roller disc cutters, requiring heavy and inflexible frame, to feed large thrust force needed to maintain penetration. The US Patent No. 4,106,577 defines a rock drilling apparatus and particularly hydro mechanical drilling tool comprising a high pressure water jet drill with a conventional drilling bit. This invention relates to the field of boring or penetrating the earth. Particularly the drilling apparatus for boring uses the combined action of fluid erosion and mechanical drilling. The US Patent No. 4,049,318 particularly defines mining machine with a water jet cutting drum for material cutting. In a mining machine a water jet pump is associated, with the assistance of cutting drums and cutting picks. This specification describes a mining machine comprising a water jet pump, rotary drum with orifices for water jet and cutting picks to assist the water jet cutting. The pump is incorporated with rotary parts and stationary cam bearing, so as to cause the pump to rotate as the drum rotates. The US Patent No. 4,314,730 describes a mineral mining machine with cutting head and a high-pressure water jet nozzle and intensifier. The machine comprises of a rotatable cutting head with picks and a high-pressure water nozzle, which directs jets of high-pressure water at the rock adjacent to cutting head. Oil pump supplies water jet from nozzle. Intensifier provides an auxiliary cutting and breaking action, easing the load on the cutting head. The US Patent No. 5,114,213 describes a high pressure water assisted mining and tunneling machine, comprising of rotary cutting means like rotating drum with picks, radial piston pump to supply high pressure water through nozzles located on the periphery of the rotating drum. The radial piston pump is mounted with cutting drum having suitable mountings. Drawbacks of known art The mining machine or the tunneling machine is assisted by the water jet to reduce the load on the mining or the tunneling machine. Further it is to reduce the wear and tear of the cutting tool and to increase the production. It is also required to deploy and operate both the cutting machine unit such as road header or drum cutter and the water jet unit. In the existing system, nozzle is located on the cutting means e.g., cutter, road header. However, the high-pressure pump unit is located away from the cutting machine units to protect it from the falling debris and such materials. As a result, hosepipe connecting the pump and nozzle has to be quite long and becomes vulnerable to damage by the falling rocks. However in some cases, the pump is unit is also incorporated in the cutting machine unit. They are mechanically complicated and suffer from the disadvantage of water leakage, which could contaminate the lubrication oil usually present in such ranging arms where gear boxes and other drive means for driving the cutting are housed. Further, when the cutting drum rotates during operation, the nozzles thereon require a high-pressure water jet only during a part of each revolution of the drum and hence expensive water swivels and sequence valves are required for such system. This makes the maintenance of the pump unit very complicated. Objects of the invention The object of this invention is to develop an efficient excavation method and the system for excavation of tunnels and vertical shafts using the water jet cutting technology. The main components of the system for excavation comprises of 1. high pressure water jet pump 2. hydraulic hose with suitable nozzles 3. proper mechanical arms to hold and position the nozzles These components are very useful in achieving better productivity oriented excavation. It is another object of this invention to house high-pressure pump unit as close as possible to the cutting machine equipments but the high-pressure hosepipe connecting the pump unit and the cutting machine is not damaged by the falling materials. It is another object of this invention, to make the system as simple as possible and less complicated due to positioning of the high-pressure pump unit within a very close proximity of the cutting machine unit and requirement of expensive water swivels and sequence valves, due to the fact that the operation is continuous without any break and for longer duration, at remote project locations. It is another object of this invention is to make water jet with appropriate nozzle holding arm to cut and excavate rock by water jet alone. Principles of the invention i) Water jet of required pressure, from a high-pressure pump to cut rock to required depth of penetration to achieve required output. ii) Suitable nozzle orifice size to get required water discharge. iii) Appropriate nozzle holding arm to carry out the excavation. As per first principle or concept, water jet unit with appropriate nozzle holding arm will operate to cut and excavate rock material by water jet alone. As per second principle or concept, water jet unit with an appropriate nozzle holding arm will be operating to cut the rock mass into suitable grid pattern for pre-weakening the rock mass at the cutting face. Subsequently an excavator will knock down the pre-weakened rock mass. As per third principle or concept, water jet unit with a nozzle holding arm will cut and weaken rock mass radially, through a pre-drilled hole in 3 or 4 vertical planes and subsequently excavator knocks off weakened rock mass. Differences / distinguishing features between the invention and prior art In the prior art the main cutting machine unit and the water jet unit operate together, whereas in the invention it is only the water jet alone or the water jet cutting operates first and then knocking off of the rock by the excavator. In the prior art the water jet unit plays an assisting role for the main cutting machine unit, whereas in the invention the water jet unit operation is the main component of the excavation work and the mechanical means required is only a simple excavator as a secondary component to knock of the rock. Statement of Invention According to this invention, the excavation method comprises of i. making a groove at the bottom most part of the cutting face first; ii. locating nozzles on the cutting face to start cutting simultaneously; iii. vertical nozzle being fixed at a predetermined into the rock face through the said groove made; iv. vertical nozzle to start cutting rock face ahead of horizontal nozzle, at a predetermined distance depending upon the nature of rock face; v. horizontal nozzle cut the rock face at an offset to the vertical nozzle and weaken the rock mass for breaking; vi. excavator unit finally knocking off the weakened rock mass from the bottom to upward. According to another feature of this invention, the nozzle sizes are chosen preferably between 1.1 mm to 1.8 mm depending on the nature of the rock, but both the nozzles being used simultaneously. According to another feature of this invention, alternatively the excavation method comprises of i. fixing plurality of nozzles horizontally on the cutter head; ii. spacing of nozzles being fixed to suit the nature of rock at the cutting face; iii. making a suitable grid pattern on the cutting face for both the nozzles fixed horizontally to start cutting operation simultaneously; iv. cutting operation being carried out on the full cutting face in the said suitable grid pattern resulting in pre-weakening of the rock mass; v. excavator unit finally knocking off the pre-weakened rock mass. According to another feature of this invention, the nozzle sizes are chosen preferably between 1.1 mm to 1.8 mm depending on the nature of the rock, but one or two nozzles being used at a given time. According to yet another feature of this invention, the system for the excavation of tunnels to carry out the said excavation method comprises of i. movably balanced nozzle holding arm ii. cutter head being fitted at the arm front iii. plurality of nozzles, preferably two nozzles, being fixed in the said cutter head with rigid lances, such that one nozzle in the horizontal direction to force the water jet normal to the cutting face and another nozzle kept in the vertical direction to force the water jet from the bottom of the cutting face for pre-weakening of the rock mass; iv. excavator unit for knocking off the said pre-weakened rock mass. According to yet another feature of this invention, the system for the excavation of tunnels to carry out the said excavation method comprises that nozzle holding arm has swing motion both in vertical and horizontal direction. According to yet another feature of this invention, the system for the excavation of tunnels to carry out the said excavation method comprises that swing motion of the said nozzle holding arm is effected by servo motors. According to yet another feature of this invention, the system for excavation of tunnels to carry out said excavation method comprises that the said servo motors are controlled by CNC drives for controlling the fine feed movements. According to yet another feature of this invention, the system for the excavation of tunnels to carry out the said excavation method comprises that the said nozzle-holding arm is statically balanced with dead weights for equipment stability in working conditions. According to yet another feature of this invention, the system for the excavation of tunnels to carry out the said excavation method comprises that the operation of the nozzle is flexible, either in both directions simultaneously or one at a time with suitable control valves. The invention will now be described in greater detail with reference to the accompanying drawings, wherein, Fig.l shows the excavation method 1 using the water jet alone Fig.2 shows cutting slots in the grid pattern made during excavation process Fig.3 shows vertical cut made from bottom and horizontal cut from the front Fig.4 shows the placement of nozzle holding frame housing the nozzles. Fig. 5 shows the cutting of the rock mass in a grid pattern for pre-weakening Mode of construction of different parts Referring to the figures in the accompanying drawings, the excavation method for tunnel, shafts and rocks using water jet cutting starts with making a groove 3 at the bottom most part of the cutting face. Then nozzles 5 & 6 are fixed on the cutter head 9 to start cutting simultaneously. A vertical nozzle 6 is fixed into the rock face through said groove. Vertical nozzle 6 starts cutting rock face ahead of horizontal nozzle 5, at a predetermined distance depending upon the nature of rock face. Horizontal nozzle 5 cuts rock face at an offset to vertical nozzle 6 and weakens rock mass for breaking. Excavator unit knocks off weakened rock mass from bottom to upward. Nozzle sizes are chosen between 1.1 mm to 1.8 mm depending on the nature of the rock, but both nozzles are used simultaneously. Excavation method alternatively comprises of fixing plurality of nozzles 5 & 6 horizontally on the cutter head. Nozzles are fixed to suit nature of rock at the cutting face. A grid pattern 4 is made on the cutting face for both the nozzles 5 & 6 fixed horizontally to start cutting operation simultaneously on the full cutting face, resulting in pre-weakening of the rock mass. Excavator unit knocks off the pre-weakened rock mass. Nozzle sizes are chosen between 1.1 mm to 1.8 mm depending on the nature of rock, but one or two nozzles are used at a given time. Excavation system comprises a movably and statically balanced nozzle-holding arm 2 and a cutter head 9 fitted at the arm front. Plurality of nozzles 5 & 6, are fixed in the said cutter head 9 with rigid lances. One nozzle in the horizontal direction 7 forces water jet normal to the cutting face. Another nozzle kept in vertical direction 8 forces water jet from bottom of cutting face for pre-weakening of rock mass. Excavator unit knocks off pre-weakened rock mass. Nozzle holding arm 2 has swing motion both in vertical and horizontal direction 7&8 effected by servomotors, which are controlled by CNC, drives for controlling fine feed movements. The operation of the nozzle is flexible, either in both directions simultaneously or one at a time with suitable control valves. The nozzle holding arm has a two axes swing arm type with a water jet cutter head frame fixed with two nozzles. The nozzle-holding arm 2 has swing action or motion in both vertical and horizontal directions 8 & 7 respectively by the servo motors. The swing arm is made of MS tubular fabricated and reinforced and of 8.6 meter length. The two axes swing movements are provided with servo motors. The motors are controlled by CNC drives for controlling the fine feed movements and interpolation for tracing profiles. The arm is statically balanced with dead weights for equipment stability in working conditions. The cutter head 9 is fitted at the arm front of the nozzle-holding arm 2 and the nozzles 5 & 6 are fixed with rigid lances. Swivels are provided so that the nozzle positions are always normal to the cutting face. Provision for back and forth motions are given for the cutter so that the relative position of nozzles can be adjusted. Two nozzles 5 & 6, one in the horizontal direction 7 and the other in the vertical direction 8 are fixed. The movement of the two nozzles 5 & 6 are independent. The relative position of the nozzle is adjustable. Advantages of the invention In the invention two concepts for rock excavation are being developed, one with water jet alone and the other water jet followed by mechanical excavation. The water jet unit operation is the main component of the excavation work and the mechanical means, if required, is only a simple excavator as a secondary component. Hence in the invention the operation is less complicated and also the safety for personnel and equipment can be addressed in a better way. It ensures better working environment, long life for the equipment, comparatively less cost for the consumable items, less maintenance work and hence production cost is economical. Due to the above reason, this invention is very much useful for a continuous long duration operation for the excavation of tunnel and vertical shaft in a hydroelectric project where difficult terrains are encountered. Noise, dust and smoke which are the principal pollution agents in conventional rock excavation methods in a tunnel / shaft are totally absent in this invention. This invention ensures that no vibrations are generated or transmitted thus meeting the conditions imposed on excavation methods are always satisfied. We Claim:- l)The excavation method for tunnels and vertical shafts in rock, using water jet cutting comprises of i) making a groove at the bottom most part of the cutting face first; ii) locating nozzles on the cutting face to start cutting simultaneously; iii) vertical nozzle being fixed at a predetermined into the rock face through the said groove made; iv) vertical nozzle to start cutting rock face ahead of horizontal nozzle, at a predetermined distance depending upon the nature of rock face; v) horizontal nozzle cut the rock face at an offset to the vertical nozzle and weaken the rock mass for breaking; vi) excavator unit finally knocking off the weakened rock mass from the bottom to upward. 2) The excavation method for tunnels and vertical shafts in rock, using water jet cutting as claimed in claim 1, wherein the nozzle sizes are chosen preferably between 1.1 mm to 1.8 mm depending on the nature of the rock, but both the nozzles being used simultaneously. 3) The excavation method for tunnels and vertical shafts in rock, using water jet cutting alternatively comprises of i) fixing plurality of nozzles horizontally on the cutter head; ii) spacing of nozzles being fixed to suit the nature of rock at the cutting face; iii) making a suitable grid pattern on the cutting face for both the nozzles fixed horizontally to start cutting operation simultaneously; iv) cutting operation being carried out on the full cutting face in the said suitable grid pattern resulting in pre-weakening of the rock mass; v) excavator unit finally knocking off the pre-weakened rock mass. jet cutting while using the alternative method, as claimed in claim 3, the nozzle sizes are chosen preferably between 1.1 mm to 1.8 mm depending on the nature of the rock, but one or two nozzles being used at a given time. 5) The system for the excavation of tunnels to carry out the said excavation method comprises of i. movably balanced nozzle holding arm ii. cutter head being fitted at the arm front iii. plurality of nozzles, preferably two nozzles, being fixed in the said cutter head with rigid lances, such that one nozzle in the horizontal direction to force the water jet normal to the cutting face and another nozzle kept in the vertical direction to force the water jet from the bottom of the cutting face for pre-weakening of the rock mass; iv. excavator unit for knocking off the said pre-weakened rock mass. 6) The system for the excavation of tunnels to carry out the said excavation method as claimed in claim 5, wherein the nozzle holding arm has swing motion both in vertical and horizontal direction. 7) The system for the excavation of tunnels to carry out the said excavation method as claimed in claims 5&6, comprises that swing motion of the said nozzle holding arm is effected by servo motors. 8) The system for excavation of tunnels to carry out said excavation method as claimed in claim 7, wherein the said servo motors are controlled by CNC drives for controlling the fine feed movements. 9) The system for the excavation of tunnels to carry out the said excavation method as claimed in claims 5&6, wherein the said nozzle-holding arm is statically balanced with dead weights. 10) The system for the excavation of tunnels to carry out the said excavation method as claimed in claims 5 & 6, wherein the nozzle is flexibly operable, either in both directions simultaneously or one at a time with suitable control valves. Dated this day of April 2006.

Full Text

This invention relates to excavation method for tunnels and vertical shafts in rock, in Hydroelectric Power Projects. More particularly this invention relates to excavation method for tunnels and vertical shafts in rocks, using water jet cutting and system for excavation of tunnels.
Generally the hydro electric power projects involves the construction of Dam to impound the water, intake structure, power house, Head race tunnels to convey the water from the intake to the power house and then tunnels. Normally the shape of the tunnel is D shape or Horseshoe shape and the diameter varies from 7.0 Meters to 10.0 Meters based on the design capacity of the project. The length of the tunnel will be around a kilometer or more, based on the location of the river water intake and the powerhouse. The number of the tunnels and shafts is based on the capacity of the project.
Tunnels are typically constructed either using the drill and blast method or by using tunnel boring machines. The tunneling operation is a repetitive process wherein the same activities are repeated in each successive cycle. Also, it is common practice to open up more than one face of a tunnel for excavation, so that the project can be expedited.
Basis of the invention
The applicant had the necessity of executing a 2000 MW Hydro Electric project in the North Eastern region, wherein 8 numbers of 9.5 meter diameter horseshoe shaped Head Race Tunnels (HRT), having lengths varying from 630 mts. To 1145mts. And 8 numbers of 8.0 meter diameter vertical shafts and adit tunnels had to be excavated in the rock. Due to the nature of the rock and seismic severity of the site, tunneling activity have to be done by

non-explosive methods only, which culminated in the application of water jet cutting technology in the project leading to the development of this novel excavation method and system for excavation of tunnels.
Prior art
Drilling or cutting high-strength rock is earlier achieved using heavy, expensive and often inflexible drills and machines to deliver the large forces needed for breakage. Then system utilising oscillating disc cutting (ODC), has been first tested cutting high-strength granite (greater than 250 MPa UCS) at relatively high speeds, using a lightweight support structure.
In contrast to conventional disc cutters, which require high compressive loads to fracture rock, the ODC system exploited the tensile weakness of rock through 'undercutting1. This allowed strong rock to be cut using lower forces. As a means of excavating hard rock, the ODC system promises a safer, cleaner and cheaper alternative to drilling and blasting. There are likely to be multiple applications in mining and civil engineering for the small, highly maneuverable, continuous excavation machines.
It was also investigated that the effectiveness of improved tool materials, in conjunction with cutter assistance methods such as water jets. Water-jet assisted cutting reduces the forces acting on tools and thus, their susceptibility to wear, by using high-velocity water jets to cool the tool during excavation.
Water-jet-assisted cutting of minerals is quite recent technology. Production type water-jet-assisted road headers have been in use in underground mines for quite some time. Also, in North America, Europe and Japan, companies are developing water jet assisted drilling equipment. Most of the aforementioned cutting and drilling equipment are in the prototype and pre-production stages. Every equipment manufacturer uses different

components for its water-jetting system. It is expected that water-jet-assisted cutting and drilling technology will be widely used by the mining and construction industries within this decade.
It has been known for some time that water jets of moderate pressure (below 100 MPa) are effective in assisting drag bit cutting of rocks, provided that they are directed onto a rock region close to the tool tip, and the water jets lead to a substantial reduction of the tool forces. The actual physical process underlying this effect is still poorly understood, so that the technique has not yet been optimized.
There are two basic limitations to a generalized application of mechanical rock excavation techniques. One is rock hardness and abrasiveness, the other is resulting inflexibility of machines designed to excavate hard rocks. Relatively light and flexible machines, like Road headers, are. used in soft rock formations. Their drag bit cutter tools, however, are very sensitive to rock hardness and abrasiveness. In hard rock formations, it is necessary to use roller disc cutters, requiring heavy and inflexible frame, to feed large thrust force needed to maintain penetration.
The US Patent No. 4,106,577 defines a rock drilling apparatus and particularly hydro mechanical drilling tool comprising a high pressure water jet drill with a conventional drilling bit. This invention relates to the field of boring or penetrating the earth. Particularly the drilling apparatus for boring uses the combined action of fluid erosion and mechanical drilling.
The US Patent No. 4,049,318 particularly defines mining machine with a water jet cutting drum for material cutting. In a mining machine a water jet pump is associated, with the assistance of cutting drums and cutting picks. This specification describes a mining machine comprising a water jet pump, rotary drum with orifices for water jet and cutting picks to assist the water jet

cutting. The pump is incorporated with rotary parts and stationary cam bearing, so as to cause the pump to rotate as the drum rotates.
The US Patent No. 4,314,730 describes a mineral mining machine with cutting head and a high-pressure water jet nozzle and intensifier. The machine comprises of a rotatable cutting head with picks and a high-pressure water nozzle, which directs jets of high-pressure water at the rock adjacent to cutting head. Oil pump supplies water jet from nozzle. Intensifier provides an auxiliary cutting and breaking action, easing the load on the cutting head.
The US Patent No. 5,114,213 describes a high pressure water assisted mining and tunneling machine, comprising of rotary cutting means like rotating drum with picks, radial piston pump to supply high pressure water through nozzles located on the periphery of the rotating drum. The radial piston pump is mounted with cutting drum having suitable mountings.
Drawbacks of known art
The mining machine or the tunneling machine is assisted by the water jet to reduce the load on the mining or the tunneling machine. Further it is to reduce the wear and tear of the cutting tool and to increase the production. It is also required to deploy and operate both the cutting machine unit such as road header or drum cutter and the water jet unit.
In the existing system, nozzle is located on the cutting means e.g., cutter, road header. However, the high-pressure pump unit is located away from the cutting machine units to protect it from the falling debris and such materials. As a result, hosepipe connecting the pump and nozzle has to be quite long and becomes vulnerable to damage by the falling rocks.
However in some cases, the pump is unit is also incorporated in the cutting machine unit. They are mechanically complicated and suffer from the disadvantage of water leakage, which could contaminate the lubrication oil

usually present in such ranging arms where gear boxes and other drive means for driving the cutting are housed.
Further, when the cutting drum rotates during operation, the nozzles thereon require a high-pressure water jet only during a part of each revolution of the drum and hence expensive water swivels and sequence valves are required for such system. This makes the maintenance of the pump unit very complicated.
Objects of the invention
The object of this invention is to develop an efficient excavation method and the system for excavation of tunnels and vertical shafts using the water jet cutting technology. The main components of the system for excavation comprises of
1. high pressure water jet pump
2. hydraulic hose with suitable nozzles
3. proper mechanical arms to hold and position the nozzles
These components are very useful in achieving better productivity oriented excavation.
It is another object of this invention to house high-pressure pump unit as close as possible to the cutting machine equipments but the high-pressure hosepipe connecting the pump unit and the cutting machine is not damaged by the falling materials.
It is another object of this invention, to make the system as simple as possible and less complicated due to positioning of the high-pressure pump unit within a very close proximity of the cutting machine unit and requirement of expensive water swivels and sequence valves, due to the fact that the operation is continuous without any break and for longer duration, at remote project locations.

It is another object of this invention is to make water jet with appropriate nozzle holding arm to cut and excavate rock by water jet alone.
Principles of the invention
i) Water jet of required pressure, from a high-pressure pump to cut
rock to required depth of penetration to achieve required output.
ii) Suitable nozzle orifice size to get required water discharge.
iii) Appropriate nozzle holding arm to carry out the excavation.
As per first principle or concept, water jet unit with appropriate nozzle holding arm will operate to cut and excavate rock material by water jet alone.
As per second principle or concept, water jet unit with an appropriate nozzle holding arm will be operating to cut the rock mass into suitable grid pattern for pre-weakening the rock mass at the cutting face. Subsequently an excavator will knock down the pre-weakened rock mass.
As per third principle or concept, water jet unit with a nozzle holding arm will cut and weaken rock mass radially, through a pre-drilled hole in 3 or 4 vertical planes and subsequently excavator knocks off weakened rock mass.
Differences / distinguishing features between the invention and prior art
In the prior art the main cutting machine unit and the water jet unit operate together, whereas in the invention it is only the water jet alone or the water jet cutting operates first and then knocking off of the rock by the excavator. In the prior art the water jet unit plays an assisting role for the main cutting machine unit, whereas in the invention the water jet unit operation is the main

component of the excavation work and the mechanical means required is only a simple excavator as a secondary component to knock of the rock.
Statement of Invention
According to this invention, the excavation method comprises of
i. making a groove at the bottom most part of the cutting face first;
ii. locating nozzles on the cutting face to start cutting simultaneously;
iii. vertical nozzle being fixed at a predetermined into the rock face through
the said groove made; iv. vertical nozzle to start cutting rock face ahead of horizontal nozzle, at a
predetermined distance depending upon the nature of rock face; v. horizontal nozzle cut the rock face at an offset to the vertical nozzle and
weaken the rock mass for breaking; vi. excavator unit finally knocking off the weakened rock mass from the
bottom to upward. According to another feature of this invention, the nozzle sizes are chosen preferably between 1.1 mm to 1.8 mm depending on the nature of the rock, but both the nozzles being used simultaneously.
According to another feature of this invention, alternatively the excavation method comprises of
i. fixing plurality of nozzles horizontally on the cutter head; ii. spacing of nozzles being fixed to suit the nature of rock at the cutting face; iii. making a suitable grid pattern on the cutting face for both the nozzles
fixed horizontally to start cutting operation simultaneously; iv. cutting operation being carried out on the full cutting face in the said
suitable grid pattern resulting in pre-weakening of the rock mass; v. excavator unit finally knocking off the pre-weakened rock mass.

According to another feature of this invention, the nozzle sizes are chosen preferably between 1.1 mm to 1.8 mm depending on the nature of the rock, but one or two nozzles being used at a given time.
According to yet another feature of this invention, the system for the excavation of tunnels to carry out the said excavation method comprises of i. movably balanced nozzle holding arm ii. cutter head being fitted at the arm front
iii. plurality of nozzles, preferably two nozzles, being fixed in the
said cutter head with rigid lances, such that one nozzle in the
horizontal direction to force the water jet normal to the cutting
face and another nozzle kept in the vertical direction to force the
water jet from the bottom of the cutting face for pre-weakening
of the rock mass;
iv. excavator unit for knocking off the said pre-weakened rock mass.
According to yet another feature of this invention, the system for the
excavation of tunnels to carry out the said excavation method comprises that
nozzle holding arm has swing motion both in vertical and horizontal direction.
According to yet another feature of this invention, the system for the
excavation of tunnels to carry out the said excavation method comprises that
swing motion of the said nozzle holding arm is effected by servo motors.
According to yet another feature of this invention, the system for excavation
of tunnels to carry out said excavation method comprises that the said servo
motors are controlled by CNC drives for controlling the fine feed movements.
According to yet another feature of this invention, the system for the
excavation of tunnels to carry out the said excavation method comprises that
the said nozzle-holding arm is statically balanced with dead weights for
equipment stability in working conditions.

According to yet another feature of this invention, the system for the
excavation of tunnels to carry out the said excavation method comprises that
the operation of the nozzle is flexible, either in both directions simultaneously
or one at a time with suitable control valves.
The invention will now be described in greater detail with reference to the
accompanying drawings, wherein,
Fig.l shows the excavation method 1 using the water jet alone
Fig.2 shows cutting slots in the grid pattern made during excavation process
Fig.3 shows vertical cut made from bottom and horizontal cut from the front
Fig.4 shows the placement of nozzle holding frame housing the nozzles.
Fig. 5 shows the cutting of the rock mass in a grid pattern for pre-weakening
Mode of construction of different parts
Referring to the figures in the accompanying drawings, the excavation method for tunnel, shafts and rocks using water jet cutting starts with making a groove 3 at the bottom most part of the cutting face. Then nozzles 5 & 6 are fixed on the cutter head 9 to start cutting simultaneously. A vertical nozzle 6 is fixed into the rock face through said groove. Vertical nozzle 6 starts cutting rock face ahead of horizontal nozzle 5, at a predetermined distance depending upon the nature of rock face. Horizontal nozzle 5 cuts rock face at an offset to vertical nozzle 6 and weakens rock mass for breaking. Excavator unit knocks off weakened rock mass from bottom to upward. Nozzle sizes are chosen between 1.1 mm to 1.8 mm depending on the nature of the rock, but both nozzles are used simultaneously.
Excavation method alternatively comprises of fixing plurality of nozzles 5 & 6 horizontally on the cutter head. Nozzles are fixed to suit nature of rock at the cutting face. A grid pattern 4 is made on the cutting face for both the nozzles 5 & 6 fixed horizontally to start cutting operation

simultaneously on the full cutting face, resulting in pre-weakening of the rock mass. Excavator unit knocks off the pre-weakened rock mass. Nozzle sizes are chosen between 1.1 mm to 1.8 mm depending on the nature of rock, but one or two nozzles are used at a given time.
Excavation system comprises a movably and statically balanced nozzle-holding arm 2 and a cutter head 9 fitted at the arm front. Plurality of nozzles 5 & 6, are fixed in the said cutter head 9 with rigid lances. One nozzle in the horizontal direction 7 forces water jet normal to the cutting face. Another nozzle kept in vertical direction 8 forces water jet from bottom of cutting face for pre-weakening of rock mass. Excavator unit knocks off pre-weakened rock mass. Nozzle holding arm 2 has swing motion both in vertical and horizontal direction 7&8 effected by servomotors, which are controlled by CNC, drives for controlling fine feed movements. The operation of the nozzle is flexible, either in both directions simultaneously or one at a time with suitable control valves. The nozzle holding arm has a two axes swing arm type with a water jet cutter head frame fixed with two nozzles. The nozzle-holding arm 2 has swing action or motion in both vertical and horizontal directions 8 & 7 respectively by the servo motors.
The swing arm is made of MS tubular fabricated and reinforced and of 8.6 meter length. The two axes swing movements are provided with servo motors. The motors are controlled by CNC drives for controlling the fine feed movements and interpolation for tracing profiles. The arm is statically balanced with dead weights for equipment stability in working conditions. The cutter head 9 is fitted at the arm front of the nozzle-holding arm 2 and the nozzles 5 & 6 are fixed with rigid lances. Swivels are provided so that the nozzle positions are always normal to the cutting face. Provision for back and

forth motions are given for the cutter so that the relative position of nozzles
can be adjusted.
Two nozzles 5 & 6, one in the horizontal direction 7 and the other in the vertical direction 8 are fixed. The movement of the two nozzles 5 & 6 are independent. The relative position of the nozzle is adjustable.
Advantages of the invention
In the invention two concepts for rock excavation are being developed, one
with water jet alone and the other water jet followed by mechanical
excavation.
The water jet unit operation is the main component of the excavation work
and the mechanical means, if required, is only a simple excavator as a
secondary component.
Hence in the invention the operation is less complicated and also the safety for
personnel and equipment can be addressed in a better way.
It ensures better working environment, long life for the equipment,
comparatively less cost for the consumable items, less maintenance work and
hence production cost is economical.
Due to the above reason, this invention is very much useful for a continuous
long duration operation for the excavation of tunnel and vertical shaft in a
hydroelectric project where difficult terrains are encountered.
Noise, dust and smoke which are the principal pollution agents in
conventional rock excavation methods in a tunnel / shaft are totally absent in
this invention.
This invention ensures that no vibrations are generated or transmitted thus
meeting the conditions imposed on excavation methods are always satisfied.

We Claim:-
l)The excavation method for tunnels and vertical shafts in rock, using water
jet cutting comprises of
i) making a groove at the bottom most part of the cutting face first;
ii) locating nozzles on the cutting face to start cutting simultaneously;
iii) vertical nozzle being fixed at a predetermined into the rock face through
the said groove made;
iv) vertical nozzle to start cutting rock face ahead of horizontal nozzle, at a
predetermined distance depending upon the nature of rock face;
v) horizontal nozzle cut the rock face at an offset to the vertical nozzle and
weaken the rock mass for breaking;
vi) excavator unit finally knocking off the weakened rock mass from the
bottom to upward.
2) The excavation method for tunnels and vertical shafts in rock, using water jet cutting as claimed in claim 1, wherein the nozzle sizes are chosen preferably between 1.1 mm to 1.8 mm depending on the nature of the rock, but both the nozzles being used simultaneously.
3) The excavation method for tunnels and vertical shafts in rock, using water jet cutting alternatively comprises of
i) fixing plurality of nozzles horizontally on the cutter head;
ii) spacing of nozzles being fixed to suit the nature of rock at the cutting
face; iii) making a suitable grid pattern on the cutting face for both the nozzles
fixed horizontally to start cutting operation simultaneously; iv) cutting operation being carried out on the full cutting face in the said
suitable grid pattern resulting in pre-weakening of the rock mass; v) excavator unit finally knocking off the pre-weakened rock mass.

jet cutting while using the alternative method, as claimed in claim 3, the nozzle sizes are chosen preferably between 1.1 mm to 1.8 mm depending on the nature of the rock, but one or two nozzles being used at a given time.
5) The system for the excavation of tunnels to carry out the said excavation
method comprises of
i. movably balanced nozzle holding arm
ii. cutter head being fitted at the arm front
iii. plurality of nozzles, preferably two nozzles, being fixed in the said cutter head with rigid lances, such that one nozzle in the horizontal direction to force the water jet normal to the cutting face and another nozzle kept in the vertical direction to force the water jet from the bottom of the cutting face for pre-weakening of the rock mass;
iv. excavator unit for knocking off the said pre-weakened rock mass.
6) The system for the excavation of tunnels to carry out the said excavation
method as claimed in claim 5, wherein the nozzle holding arm has swing
motion both in vertical and horizontal direction.
7) The system for the excavation of tunnels to carry out the said excavation
method as claimed in claims 5&6, comprises that swing motion of the said
nozzle holding arm is effected by servo motors.
8) The system for excavation of tunnels to carry out said excavation method
as claimed in claim 7, wherein the said servo motors are controlled by CNC
drives for controlling the fine feed movements.
9) The system for the excavation of tunnels to carry out the said excavation
method as claimed in claims 5&6, wherein the said nozzle-holding arm is
statically balanced with dead weights.

10) The system for the excavation of tunnels to carry out the said excavation method as claimed in claims 5 & 6, wherein the nozzle is flexibly operable, either in both directions simultaneously or one at a time with suitable control valves.
Dated this day of April 2006.

Documents:

1300-che-2005 abstract duplicate.pdf

1300-che-2005 claims duplicate.pdf

1300-che-2005 description (complete) duplicate.pdf

1300-che-2005 drawings duplicate.pdf

1300-che-2005-abstract.pdf

1300-che-2005-claims.pdf

1300-che-2005-correspondnece-others.pdf

1300-che-2005-correspondnece-po.pdf

1300-che-2005-description(complete).pdf

1300-che-2005-description(provisional).pdf

1300-che-2005-drawings.pdf

1300-che-2005-form 1.pdf

1300-che-2005-form 26.pdf

1300-che-2005-form 9.pdf

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Patent Number

222657

Indian Patent Application Number

1300/CHE/2005

PG Journal Number

47/2008

Publication Date

21-Nov-2008

Grant Date

20-Aug-2008

Date of Filing

15-Sep-2005

Name of Patentee

LARSENT & TOUBRO LTD

Applicant Address

ECC DIVISION, MOUNT POONAMALLEE ROAD, MANAPAKKAM, CHENNAI - 89,

Inventors:

#	Inventor's Name	Inventor's Address
1	NARASIMHAN RAGHAVAN	ECC DIVISION, MOUNT POONAMALLEE ROAD, MANAPAKKAM, CHENNAI - 600 089,

PCT International Classification Number

E02D17/06

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1			NA