Impact of Geotechnical Engineering on Tunnel Construction - Essay Example

Impact of geotechnical engineering on tunnel construction affiliation Geotechnical engineering Geotechnical engineering as a branch of civil engineering is mostly concerned with the study and management of the earth materials. In addition to its importance in civil engineering, Geotechnical engineering also is applied in petroleum, mining, military and a number of other engineering disciplines that are involved with the construction of structures on either the surface or underground. To investigate surface materials and conditions, Geotechnical engineering utilises both rock mechanics and soil mechanics principles to establish the relevant chemical and mechanical/physical properties of these materials. By so doing, the Geotechnical engineers are able to evaluate man made soil deposits and natural slope stability, perform the site risk assessment, and design all forms of structure foundations and earthwork. Furthermore, they do monitor the condition at the site during the construction of the structure foundations or earth works Primarily, the use of soil, earth service and underground has been in place for quite a long time. For instance, in the ancient Egypt and Mesopotamia, soil was used as material for controlling floods, building various foundations, burial sites and lastly as material for constructing buildings. Up to the 18th century, soil design was an art that relied on one’s past experience to come up with a structure on it without any scientific orientation in the field (Santamarina & Cho 2011). However, there were developments in the sector over time rising form catastrophes and advanced need to develop stable structures. Ultimately, soil design a scientific discipline did arise. Soil design as a scientific discipline remained rudimentary up to the 20th century in the year 1925 when Geotechnical engineering was born. According to Sousa & Einstein, (2012) Karl who was a mechanical engineer and geologist, explained the fact that shear strengths of the soil can be controlled by utilising effective scientific models on the soil structures. . He was able to describe the behaviour of soil using a number of theories, a factor that is so fundamental in the industry. It became clear that, soil could be controlled by use of scientific methods to support quite a number of structure in different places by control of the soil behaviour of those areas. Concisely, the main function of Geotechnical engineer in the contemporary construction is fundamental in avoidance of disasters that might arise from earthworks or construction related to surface behaviour. Some of the major activities carried out in the process include the study of soil and rock properties underlying structures and those adjacent to it. This study is important because they are likely to affect the structure in case there is the shear of the soil. Geotechnical engineering is very important too when repairing a distressed construction or earthwork that is due to the conditions of the surface around the structures. Geotechnical in tunnel construction Tunnels are pass ways for either human, vehicles or delivery of fluids for domestic and industrial uses either constructed underground or under water. They are dug through surrounding soil/rock/earth and they are usually enclosed except at the ends where there is an exit or an entrance. Tunnels have a wide range of use, which include vehicle or foot traffic, rail traffic or canals (Špačková et al. 2013). Most recently, tunnels have been adopted for use in rapid transport systems to optimise safety on both human beings and animals who may be using the same route at the same time with the trains. In addition, some tunnels are used to supply large amounts of water that may be needed for either domestic consumption or that used in hydroelectric station or for transporting sewers. Utility tunnels have also gained popularity in serving as passages for people from one building to another, for supplying chilled water, electrical power, routing steam or delivering telecommunication cables. Most significantly, there is an inevitable use of the tunnels today due to the convenience and safety. It is important that all safety precautions be looked into before a tunnel is presented as fit for use. These precautions are taken care of during the construction process by use of various principles and professionals. Geotechnical engineers are some of the very crucial professional who predetermine the safety of the tunnels at last. Thus, this discipline serves a great purpose in the bid to solve the transport systems by providing safe tunnels as options. By so doing, Geotechnical engineering could have solved one of the major challenges today, which is congestion on roads, which also comes in with a lot of pollution that has led to global warming. Role of Geotechnical in tunnel construction The tunnel builders and designers consider rock and soil surrounding a tunnel as building material. This is apparent because, they provide support to the hole before tunnel supporters are put in place. Hence, it is important for the builders and the designers of the tunnel to know the exact time that the tunnel will be able to support itself before supporters are put in place so as to ascertain the safety of the workers. Furthermore, it is important to know the future effects of the surroundings on the tunnels after some other natural activities like arching so as they can be able to establish the total load carrying capacity of the tunnel supporters. Through geology, one is able to predetermine the cost, behaviour and feasibility of any tunnel. Acceding to Santamarina & Cho (2011) construction of tunnel has fewer disputes and cost overruns during the process of construction when there is adequate inclusion of Geotechnical investigation in the planning process. Unlike when there are un-anticipated delays, which can turn costly in terms of both time and cash. Concisely, exploration carried out by the Geotechnical engineers, help in the process of evaluating the feasibility, economics, safety and design of the tunnel project as a whole. Challenges of the underground while construction a tunnel The underground presents with substantially difficult challenges, however, these challenges are not impossible to the tunnel design team if they include Geotechnical engineers from the initial planning phase of the construction. Sometimes, the prediction of the Geotechnical engineers may not be precise, but they are worth trying than having not well-experienced structural engineers go on with a construction process without the Geotechnical engineer. Geologic engineers tackles a number of underground challenges in the process of developing structure that are aimed at providing service to people. Some of the underground challenges include the vast uncertainty that is associated with underground projects, determining the cost and feasibility of the project by having a close study of the surrounding soil materials and precise knowledge of the regional hydrogeology and geology. Additionally, ground water in the region must be studied well despite the fact that it is difficult to predict -water is the most troublesome parameter during the construction process. It guides the engineering properties as they sometimes change drastically with a wide range of conditions that may include seasons, rate and loading direction, seasons among others. In this case, geological engineering comes in handy to ensure that there is smooth operations while handling underground tunnels. Geotechnical engineering, makes it possible, to construct these underground structures with minima dangers and cost by bypassing the huddles encountered while exploring the underground. As a consequence of understanding this impending challenges the builder and designer, will be able to prepare adequately in anticipation of the major challenges. At the same time, well-understood composition of the surface and ground, will lead to safe construction process. In most instances, people involved in tunnel construction may be faced with catastrophes like the holes closing them in more especially when they are not aware of the length of time that a hole can support itself before it closes up. In addition, geological technology provides the builder with the measurements of the width and height that are safe to work under so that they can provide with a much longer self-supporting time before the tunnel supporters are put in place. Importance of Geotechnical in tunnel construction Involving Geotechnical engineers in tunnel construction has proved to be of much importance in construction. In particular, timely involvement of Geotechnical engineers mitigates the cost of operation in most of these projects. The United States national committee on tunnelling technology confirmed that after carrying out a study determining the end cost of projects where these engineers were involved in the planning process and when they were not. From the study, in most projects where Geotechnical engineers were not used, the total cost was sometimes 50 percent more of the engineers estimated price (Tak et al. 2011). In most instances, the escalating cost arose from tackling of un-anticipated problems during the construction process. On the other hand, where Geotechnical engineers were involved, the escalation costs averaged 12 percent more of the estimated cost. This for the fact that, most of the issues encountered in the process, can be managed or avoided if anticipated timely. In essence, the involvement of Geotechnical in the process will enable the builder to identify the possible issues early enough allowing for timely action, which is likely to mitigate the cost at large. Secondly, these engineers determine the load on the tunnel even after the construction is completed. This will lead to building tunnel supporters that can bear underlying weight even if arching of the surrounding soil/rock took place (Kim & Bruland 2009). On the long run, this cautious calculation of these engineers will go in a long way to save lives of the users of that tunnel as much as they provide an alternative transporting system too. The structure and composition of the soil or rock along the tunnel alignments, is very important while making decisions on construction, designing and planning of a tunnel. The Geotechnical services of data collection should be initiated immediately, while planning for the construction, it should continue through the construction period and even after the construction to establish the behaviour of that particular tunnel while in service. This will be helpful in determining any hiccups early enough so that the tunnel can be considered safe to use at the same time achieving its full potential. Use of a tunnel can be halted at this point in case any hiccups are noted so that it paves way for repair and realigning to ensure that it meets safety standards. For underground constructions, Geotechnical investigations are carried out differently from the way they are done when constructing other surface projects. This is because the engineer has to estimate the cost; hence, there is a need for anticipation of the tunnels behaviour under different lining and excavation scenarios. Conclusion It is of the essence that, there is careful planning of the Geotechnical investigations taking into account the fact that there is vast uncertainty associated. This means that the Geotechnical engineer has to go deep in the investigation until they get the right kind of information for the project at hand. Depending on the project and location, the Geotechnical engineer can decide the scope of his or her investigation. The United States national committee for tunnel construction, approved that Geotechnical investigation, should at least consume a three percent of the whole project. By so doing, enough funds will be provided to ensure that the project runs smoothly. After the study of the structure of the tunnel alignment is complete, it is important that the Geotechnical engineer do a study on the contractor needs. This will involve informing the contractor on what materials and equipment to use at any point in the construction process. This again goes down to mitigating the cost of operation since the contractor will be having prior knowledge on what they need to carry out the project successfully. Apart from saving on financial expenditure, at the same time save on time consumed in the construction the whole tunnel. Concisely, Geotechnical has come in to help the society tackle a number of issues that are of advantage to the economy while providing g convenient solutions to a myriad of problems that spill to the future generations. Reference list Kim, Y. & Bruland, A., 2009. Effect of rock mass quality on construction time in a road tunnel. Tunnelling and Underground Space Technology, 24, pp.584–591. Santamarina, J.C. & Cho, G.C., 2011. Energy geotechnology. KSCE Journal of Civil Engineering, 15, pp.607–610. Sousa, R.L. & Einstein, H.H., 2012. Risk analysis during tunnel construction using Bayesian Networks: Porto Metro case study. Tunnelling and Underground Space Technology, 27, pp.86–100. Špačková, O., Šejnoha, J. & Straub, D., 2013. Probabilistic assessment of tunnel construction performance based on data. Tunnelling and Underground Space Technology, 37, pp.62–78. Tak, S. et al., 2011. Physical ergonomic hazards in highway tunnel construction: Overview from the Construction Occupational Health Program. Applied Ergonomics, 42, pp.665–671.  Read More