Dozens of different professionals are involved in designing, building, and maintaining tunnel systems. Geologists, surveyors, civil engineers, ironworkers, cement masons, and construction crews generally put in hundreds of labor hours to ensure that a tunnel is safe, reliable, and well-maintained. Most tunnel jobs, especially those involving the construction and maintenance of structures, are city government positions, though private companies are frequently contracted to perform highly specialized work in the development of a new tunnel.
Urban geologists and surveyors take measurements and record information about the area where a tunnel is to be built. They figure the appropriate length, width, and height for a new tunnel, and attempt to predict the risk of potential hazards, such as mudslides, rock falls, earthquakes, and collapsed support systems. Geologists also make sure that the construction of a new tunnel will not disrupt ecosystems or inconvenience humans who reside in the area.
Once an area of land is deemed safe and initial measurements have been made, civil engineers get to work designing the structure. Professionals determine the exact size and shape of the new tunnel, draw blueprints, calculate the expected costs of materials and laborers, and estimate the time needed to complete construction. They present their designs to city government officials for authorization and begin scheduling the different phases of the building process. Many civil engineers spend significant amounts of time at the build site to supervise the construction of new tunnels.
Many different types of skilled laborers work in tunnel jobs that involve the actual building of new structures. Highly-trained explosive workers and blasters take final measurements and calculate the exact quantity of explosives needed to displace rocks and soil. They carefully place and detonate explosives to clear the way for construction crews. Ironworkers and metal fabricators assemble and install large beams, trusses, and columns to provide the basic framework for the tunnel. Some professionals cut, shape, and bend materials in specialized shops according to blueprints, and others lift, weld, and bolt them into place at the job site.
Professional cement masons and rebar workers hold very important tunnel jobs. They first create forms out of metal or wood to provide the framework for concrete panels and columns. Workers pour cement around reinforced metal bars in the forms and allow it to dry. Cement masons then clear any excess concrete and smooth finished panels.
Other tunnel jobs involve the construction and maintenance of roads or railways that travel through structures. Construction crews smooth the ground, pave roads, and paint lines, and electricians are contracted to run power lines and install lights. Building a reliable structure involves extensive communication and cooperation between professionals in all tunnel jobs.