Investigation Of Design And Exploration Of A Tunnel Boring Machine And Tunnel Construction

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LITRATURE REVIEW.

The design of a tunnel-boring machine

Roads are an essential section for the operation of human beings. They ensure that individuals are in a position to access diverse services all over the nation without experiencing many obstructions. In addition to that, transport supplies are needed to ensure that the supply of goods is done uniformly all over the country. The tunnel-boring machine plays a significant role in providing that the activity becomes successful; through the whole process. Therefore for a successful project, there is a need for ensuring that proper prediction of the working of the machine is done (Rober

tsonand Robertson, 2012). The process is made a reality through the determination of the design parameters associated with the machine and the functions that contribute to it working efficiently.

The machine does contain the cutting head mainly involved in the cutting process. The head is mainly characterized with the cutting discs of approximately 8 meters in diameter. The head may contain about 50 cutting discs that significantly contribute to increasing its efficiency in working. The cutting discs are further designed to be in a position to provide the forces needed for the cutting head (Font-Capó et al, 2011). The prediction of the performance of a tunnel-boring machine is primarily done basing on the cutting discs that the boring machine does harbor in carrying out its operation. Estimation is an essential section of any machine in ensuring that there is no significant difference in the result and the approximate figures. Most devices do have different ways of carrying out estimation to ensure that most of the variables involved in the whole process are achieved at the end of the day. The tunnel-boring machine does have the linear cutting test that greatly helps in the determination of the various variables established through the operation of the machine (Cho et al, 2013). One of the main parameters determined by the linear cutting test is the appropriate spacing that is needed between any two cuts that may be needed. In addition to that, the operation of the tunnel-boring machine calls for several penetrations that may be needed for its functioning. The linear cutting test does also play a significant role in determining the required penetrations. Furthermore, the device plays a significant role in determining the drive and the cutting speeds that may be needed in carrying out the whole operation process. The cutting forces can also vary depending on the kind of tunnel that is required at the end of the day and the condition of the ground that the boring machine has to encounter. The load cells greatly help in the measuring of the cutting forces allowing for the operators to carry out minor alterations of the forces being applied in the cutting process.

Proper penetration of the machine calls for an appropriate prescription of the disc at a particular place to exert the penetration. Hence, there is need of making use of the standard force. The force always has to be applied perpendicular to the rolling direction to be in a position to achieve such a function. Apart from that, the force also helps in determining the thrust of the machine if normally applied to the direction of the roll (Acaroglu, 2011). The operation of the machine calls for making use of energy to ensure that it functions efficiently. The energy has to be provided in the needed amount to ensure that the whole process becomes a success. Some of the standard requirements that call for the use of energy are the torque and power requirements needed by the machine. Determining such conditions plays a major role in establishing the specific energy required; hence, openly displaying the importance of the rolling force as it greatly helps in the determination of the power and the torque. In designing the balance of thecutting head, the side force is highly considered. The balance promotes the excellent working of the machine.

                                   

The working of a tunnel boring Machine

The operation of the boring machine calls for the combination of three major components of the apparatus. The cutter head has to be present in addition to the hydraulic bracing systems that ensure proper working of the machine. Moreover, there will be need to have the excavating conveyor and any other host of the other elements. The cutter head is made with a circular metal face (Maidl et al, 2008). Several discs are interspersed in the cutter head allowing for the cutter head to make a complete rotation of 360 degrees. The result is that the force of the machine in penetrating the tunnel is considerably boosted hence pushing for the boring machine to penetrate excellently. Through the process, the material on the surfaces is loosened with the cutter discs rolling over the surface. The surface might be made of diverse materials ranging from different rocks to the soils. Over all, the rolling of the discs promotes the breaking of such materials into small pieces being referred to as chips. While the process of the chips formation being still in progress, some of them end up falling into the broad bucket lips. The bucket lips are openings that one may quickly notice on the cutter head (Maidl, Thewes and Maidl, 2014). Shelter hoppers are formed as a result of the combination of the various bucket lips.

The hopper plays a role of receiving the excavated material in the boring process. The material is after that, extended on a vast conveyor belt system. The belt after that extends through the central body located within the tunnel-boring machine. There is a backup area at the rear of the tunnel-boring machine (Ramoni and Anagnostou, 2010). The backup area experiences gradual enlargement within the tunnel system and having access to the surface. The wheeled loading unit is after that involved in the scooping of the chips ensuring that they are placed in the muck truck. The truck is a dump vehicle and large that has a significant specialization in the traversing of the tunnel system. The systems serve as storage of the excavated material allowing for further processing of the material. The whole process involves the boring machine carrying out its activities in the tunnel. The stability of the machine in the tunnel through the whole process tends to remain still hence, indicating the high levels of stability trait associated with the machine. The hydraulic braces play a significant role in establishing such stability. The mounting is done radially on the mega drills of the body. The result is that the braces do push outwards on the walls of the tunnel ensuring to increase the stability of the boring machine.

The moving forward of the machine relies on the stabilizing of the machine. The stability is mainly attained through the simultaneous initiation of the braces. Several stretches are always needed to be cleared in the process. The safety of the tunnel is too of much importance in ensuring that the builders’ lives are safe at work and their health remains to be intact through their living. The working of the tunnel-boring machine also ensures that the security of the tunnel is maintained at high levels during the building process. Several devices are used in facilitating such safety of machines. The rock anchors form one of the primary devices; the boring machine ensures that they are well placed in the tunnels to fulfill their functions (Shahriar, Sharifzadeh and Hamidi, 2008). Apart from that, beam supports and metal mashes are also used. However, there is always the need to eliminate such devices before the completion of the tasks. Hence, a mortar and wet concrete mix is also applied before the task coming to completion to ensure that the stability of the tunnel is maintained.

                        Variation of tunnel boring machine with altitude

Progress is an essential aspect of any activity. Individuals will always tell their performance in the society depending on the progress that they do make at a particular time in the society. Machines greatly help in ensuring that the growth in carrying a specific activity is excellent and one can be in a position to clear a particular task within a short period. However, despite many relying on the machines, the performance of the machines also varies in different occasions. A machine will always offer particular results within particular set environments for example low or high altitude areas (Calheiros et al, 2011). Tunnel boring machine is one machine that will display various rates of working in different climatic conditions. When the water level is low, the rates at which the boring machine will advance into the ground is much higher compared to the high altitude areas. The case can be easily seen when the machine is used in the boring of granite. It displays high speeds of working compared to areas that the water levels are high.

The loading of a boring machine is of much importance in ensuring proper propelling of the machine into the ground. The cutters play a significant role in defining the loading that will be displayed by a particular boring machine. The oscillation of the cutter can be very fast enhancing the speed at which the boring machine will take in penetrating through the ground to create a tunnel. The working will always face different resistance depending on the nature of the ground and the environment. Understanding the forces that the cutter will have to counter as the boring machine works will play a significant role in informing one on the kind of cutters that they will have to use at the end of the day. Most of the tunnel boring machines operators will prefer areas with low altitudes citing the weak forces that the boring machines will encounter through its working. The lesser the force encountered, the lesser the loading will be needed on the cutter (Gong et al, 2012). Furthermore, the machine will make it operating through the ground as fast as possible compared to the other conditions that may be encountered when the machine is carrying out its operation in high altitude areas. Hence, the rates at which the cutters will experience wear and tear will be low, the main reason being that most of the machine devices do undergo wear and tear depending with the kind of ground forces that they do encounter on the ground through their working.

The cost of handling a particular activity will always tell the kind of profit that an individual handling a particular task will attain at the end of the day. Moreover, the clients receiving the services will have to pay for the service in varying amounts depending on the cost that the professionals will use in handling the task. Most individuals operating the tunnel boring machines will prefer offering their services in the low altitude areas compared to the high altitude areas. They do set a standard pricing to ensure consistency of its clients in seeking services from their companies (JAVAD and NARGES, 2010). Hence, their profits will vary depending with the cost incurred in offering the service around the nation. The low altitude areas provide a conducive environment for the efficient working of the tunnel-boring machine. The ground is much easy to penetrate allowing for fast penetration. Moreover, the servicing will be needed after the machine has handled multiple tasks compared to the number of task that will be needed when the machine is working high altitude areas. The result of everything is that low costs are incurred in operating the tunnel-boring machine in low altitude areas. Therefore, many will seek to work in low altitude areas.

                                                Tunnel Construction

    Any process calls for better planning and setting the needed apparatus for working ready. In addition to that, there is a need for being armed with the techniques required through the working. The methods will dictate the accuracy and the speed that will be involved in handling the diverse tasks. The methods used in the construction of the tunnels vary depending on the nature of the ground that will be encountered in handling the tunnels. Soft grounds form one of the areas that are to be constructed. One of the challenges experienced with the soft ground is that they have a higher tendency of collapsing citing the low strength that the soils do have in their operation. The lives of the individuals carrying out such tasks have to be protected through the whole process of carrying out the assignment. Therefore, one of the precautions observed in carrying out the task is that the openings of the tunnels have to be shallow. In addition to that, the openings have been offered with diverse support objects to ensure that the soil above the opening does not collapse in the process of the working. Tunnels constructed in such ground are mostly used for delivery of water from one point to another. In addition to that, they ensure the safety of the individuals living in the area by providing safe delivery of wastewater from the removal system to the appropriate areas that the water has to be disposed (Meguid et al, 2008).

The rocks are also used as a surface for the construction of the tunnels. In such cases, tough cutters are used to ensure that the tunnel boring machines get to penetrate the rocks efficiently providing that the whole task comes to a completion. Most of the tunnels are known for the strong stability that they harbor within them. Minimal support is needed for the tunnel to be operational. However, as a way of cutting down any form of risk that may be associated with the collapsing of the tunnel in the case of a vehicle going past the tunnel, an extra support is always added to assure more safety for the individuals making use of the tunnel. Trains and cars primarily make use of such tunnels in the case of them being needed to go through a particular tunnel on land. The construction of the rock tunnel calls for the use of much force and techniques to make it a success (Singh and Goel, 2011). However, the underwater tunnel has proved to be more complicated. The tunnel has to find its way under the canals, rivers, and lakes. Despite water serving as a source of life, allowing the water to get into the tunnels in such cases can lead to the death of the constructors of the tunnel or the individuals making use of the tunnel for transportation services. Therefore, the professionals work hard to ensure that water is kept away from the tunnel before and after the construction coming to a completion (Grewe, 2008). The challenges experienced in building an underwater tunnel is also experienced when one has to build a tunnel under the city. The city has diverse buildings each of them exerting their weight to the ground surface. The pressure tends to cause a degree of sagging on the underlying tunnel. The construction of such a tunnel calls for the specialists to come up with sophisticated techniques that will ensure the weight of the overlying masses are appropriately dealt with, and the tunnel is left to be safe for carrying out the different operations in the society. The tunnels do vary regarding length depending on the kind of service they will have to offer in the nation. Some of the tunnels tend to cover a short distance. The traits associated with the tunnel allows for the tunnel-boring machine to be easily used in facilitating the construction. However, other tunnels are cover long distances and call for application of different other complex techniques. It is therefore, the responsibility of any person carrying out the construction of the tunnels is to be aware of the relevant techniques that will make the whole process a success.

                                    Tunnel Maintenance

    After construction coming to a completion, the completed structure has to be enjoyed for the consecutive number of coming years. The tunnels have diverse features that have to be maintained to ensure that individuals making use of the tunnels get to experience a comfortable atmosphere in their operation. Since the car and train operators primarily make use of the tunnels, traffic devices are always contained in them to ensure that individuals making use of it get to experience comforting environments through their working (Peddie et al, 2010). Several climatic factors serve as a risk to the effective operation of such devices. Respective personnel have to ensure that they make regular checks of such devices to ensure that at no time are the activities interfered citing some of the traffic apparatus undergoing some form of destruction. Some of the tunnels go for long distances. Efficient working calls for coming up with a strategic plan that will ensure all the aspects that have to be checked and maintained have to be done before the maintenance period comes to an end. The task force charged with the responsibility of carrying out the maintenance programs organizes itself in a manner that they subdivide the tunnel into sections by setting particular intervals.

    Objects of diverse weights make use of the tunnels. There is a need for ensuring that individuals making use of the tunnels get to remain safe by ensuring that they do not experience any form of sagging as they are taking part in their activities. In addition to that, the tunnel might experience sinking if it is constructed in soft grounds. Therefore, there is a need for ensuring that constant checks are done on the state of the grounds and wall for the tunnels. The tunnel might too undergo some form of weakening of the supporting bars. However, the users of the tunnel do not know the capacity of the tunnel in withstanding such heavy loads. Most of the users make use of the regulations that were set during the start of the making of the tunnel. Hence, there is a need for the maintenance process to be done regularly. The process will check whether all the features set during the building of the tunnel are maintained. In the case of any error that may occur in the process, relevant changes are made that will provide to restore the original features of the tunnel (Van and Merci, 2008).

    The passengers making use of the tunnels in their operations expect that safety will be maintained through their traveling. Most of them have their trust in the drivers driving them around. Apart from that, the drivers can never tell the features outlined in the case of the bending of the tunnel. Therefore, lack of proper communication along the routes will lead to multiple accidents being experienced. The relevant transport authorities worked to ensure that proper signs are set on routes to correctly inform oncoming drivers of bumps and any other factors that may act as a significant barrier to the comfort driving of the different drivers. However, several things might lead to the destruction of such signs, for example, being knocked down by oncoming vehicles. The result will be that there wills no proper communication done to any other driver coming after the destruction of the signpost. Such cases call for constant checks to be done and correction of the errors that might have occurred. One of the reasons pushing for such factors is that the destroying of the signs cannot be easily seen by the professionals not making use of the tunnels. Water can also serve as one of the primary factors that can lead to the improper functioning of the tunnels. It may serve as the primary factor for the destruction of the walls and any other supporting bars set to offer support to the tunnel. Hence, there is a need for maintenances to ensure that all water seals remain to be closed and no amounts of water are allowed to flow into the tunnel from the ground (Alejano et al, 2009).

                                     Involvement of Integrated control system in tunnel construction

Lives are an essential aspect of the society. Several environmental conditions pose the lives in danger. One of the common factors is the harmful gases in the atmosphere that pose a risk to the respiratory system of the human beings. The common gases known for leading to such effects in the society are the carbon monoxide and nitrogen dioxide (Britt, Tranchemontagne and Yaghi, 2008). Apart from the harmful gases, several other gases have to be determined in the atmosphere to ensure that at no time will a specific condition occur that may pose health effects to the individuals making use of the tunnel. The integrated control systems play an essential role in ensuring that the proper monitoring of the environment is done and the right conditions established every other day.

Productivity in the nation has to be increased by ensuring high levels of efficiency in carrying out the transport activities in the society. Efficient transport offers room for faster transportation of products while they are in excellent conditions in addition to the fast offering of the diverse devices in the community. Costly damages that may occur as a result of the trucks or trains hitting the sidewalls can lead to significant losses in the economy. There is a need for efficient reduction of damages to see to it that most of the activities are carried out normally. The integrated control systems play an essential role in ensuring that the monitoring of the conveyor belts is done to cut down on such costly damages (Lepuschitz et al, 2009). The monitoring also plays a significant role in cutting down the number of accidents that may occur when the various vehicles are making use of the tunnels. The result is that the mortality rate through the accidents is substantially reduced. Ventilation of the tunnels is also of much importance to ensure that the individuals making use of the tunnels do not end up suffocating. Therefore, there is a need for offering ventilation features through the whole route. The integrated control systems play an essential role in ensuring that the ventilation is done correctly guaranteeing the safety of any individuals making use of the tunnel.

Water serves as one of the challenges facing the construction of tunnels in the society.  There is the need for dewatering any form of water that may get into the tunnel. Apart from that groundwater has also being a major challenge. The water has to be always controlled to ensure that no weak lines are established within the tunnel. The activity might interrupt with the usual transport activities that may occur within the tunnel. However, despite the understanding of the challenges associated with the water, groundwater has continuously served as one significant challenge to the operations carried within the tunnel. Pumps significantly help in controlling such occurrences in tunnels. The integrated control systems greatly help in observing the working of such pumps and ensuring that the water levels in the tunnels are maintained at low levels and the operations being carried in the tunnels remain to be safe at all times (Petite and Huff, SIPCO, 2011).

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