TECHNOLOGIES AND FEATURES OF CONSTRUCTION OF TUNNELS

ТЕХНОЛОГИИ И ОСОБЕННОСТИ СТРОИТЕЛЬСТВА ТОННЕЛЕЙ

Беркович Софья Андреевна

студент, Национальный Исследовательский Московский Государственный Строительный Университет,

РФ, г. Москва

Баклан Анастасия Алексеевна

студент, Национальный Исследовательский Московский Государственный Строительный Университет,

РФ, г. Москва

Юдина Ирина Ивановна

преподаватель, Национальный Исследовательский Московский Государственный Строительный Университет,

РФ, г. Москва

АННОТАЦИЯ

В данной статье рассматривается вопрос об особенностях строительства подземных сооружений - тоннелей; определяются преимущества и недостатки данного вида строительства; приводятся примеры существующих технологий строительства тоннелей; рассматриваются перспективы строительства тоннелей в будущем.

ABSTRACT

This article deals with the peculiarities of construction of underground structures - tunnels, it defines the advantages and disadvantages of this type of construction, it gives the examples of existing technologies in the construction of tunnels and it considers the prospects of tunnel construction in the future.

Ключевые слова: тоннели, сооружения, строительство, способ строительства тоннелей, горизонтальные, закрытые.

Keywords: tunnels, structures, construction, method of tunnel construction, horizontal, closed.

A tunnel is a horizontal or inclined man-made underground structure designed for transportation, water passage and placement of communications or industrial facilities. Tunnels are an effective way to overcome various height or contour obstacles encountered in highway design. To ensure the strength of the tunnel structure, geosynthetic materials are used to provide reliable surface reinforcement, waterproofing and drainage, which allows these tasks to be successfully performed for decades.

Figure 1. Tunnel classification

There are different types of tunnels, which differ in purpose, depth and construction methods (Figure 1). Tunnels can be used for pedestrians, cyclists, cars, trains, ships, streetcars and sewerage systems. They are built to overcome natural obstacles, reduce travel time and avoid crossing traffic flows.

Let us look at the advantages and disadvantages of tunnel construction.

Advantages include the following factors:

1. Tunnels make it possible to lay tracks and communications through mountains, rivers, seas and other obstacles, which reduces travel time and facilitates transportation
2. Tunnels allow the creation of new transportation routes, expanding infrastructure and facilitating traffic flow
3. Tunnel construction avoids the large land areas that would be occupied by surface road construction

Disadvantages include the following factors:

1. Tunnel construction usually requires significant investment due to the complexity of engineering and the use of specialized technologies
2. Tunnel construction may have adverse environmental impacts, including changes in the hydrological regime, impacts on flora and fauna, and waste and noise emissions.
3. Tunnel construction often involves technical challenges such as geologic features, resistance to water, pressure, and other factors.

Modern tunnel construction utilizes advanced technologies and innovative equipment. There are several methods of tunnel construction, which are divided into open, closed and special. And their choice depends on:

1. Tunneling sites
2. Engineering and geological conditions
3. Availability of necessary equipment
4. Dimensions of the length and cross-section of the tunnel
5. Difficulties in carrying out the work

Open methods are used for tunnel construction at shallow depths - up to 20-25 meters. In this case, the tunnel structures are fully or partially constructed in excavations or trenches. Depending on the type of tunnel, its location, and the layout of the surrounding buildings, different methods of wall bracing are used, as well as the shapes and sizes of excavations.

The closed method is used for deeper tunnel construction - from 25 meters. In this case, the ground surface is not opened during construction.

Special methods are exceptions that cannot be clearly attributed to either open or closed tunnel construction methods. For example, they are used when the ground is too watery and the method of artificial ground freezing is applied.

Tunnel boring is carried out by mining or shielding methods, which are considered to be the classic methods (except for shielding).

The mining method of construction consists of closed tunneling, in which all work is carried out without disturbing surface conditions. In this case, the tunnel is gradually excavated and temporary bracing is installed to protect the tunnel lining.

The shield method of tunnel construction is based on the use of movable support - a tunnel boring shield under which the tunnel lining is built and the ground is excavated. These systems ensure fast (up to 1 km per month) and safe tunneling in various conditions.

Tunnels with monolithic concrete or reinforced concrete linings are usually protected with external waterproofing applied over a layer of leveling spray concrete. In soils with less water saturation, internal waterproofing in combination with reinforced concrete lining can be used. In the case of very water saturated soils, internal metal insulation is used.

The choice of waterproofing solutions for tunnels depends on the following factors:

1. Geological conditions (characteristics of soils and rocks)
2. Tunnel construction method
3. Type of tunnel lining

Transverse mechanical ventilation systems are the most efficient, but they are expensive to implement and operate. These systems are divided into two types: full transverse and half transverse.

Full transverse systems provide uniform air circulation and increased fire safety. They are well suited for long tunnels with heavy traffic, but are expensive to install ductwork and associated equipment.

Semi-transverse systems supply fresh air through ducts running along the tunnel. They remove contaminated air through portals or shafts. The reverse scheme, in which air is supplied along the tunnel and exhausted through an exhaust duct, is called a semi-transverse scheme.

Many large-scale global transportation infrastructure expansion projects are currently under development around the world, including underwater, mountain and urban tunnels of unprecedented scale and complexity. The most notable among them are underwater tunnel projects:

1. "Eurasia-America" through the Bering Strait
2. "Europe-Africa" through the Strait of Gibraltar
3. Underwater tunnel system connecting Japan to the mainland via South Korea and Sakhalin Island

These projects are planned to improve the global transportation network, reducing travel time, improving trade and promoting economic growth.

In conclusion, it should be noted that the development of tunnel construction technologies and methods makes it possible to effectively solve transportation and infrastructure problems while ensuring the safety and sustainability of the structures. It is important to continue to improve tunnel construction processes in order to increase their efficiency and environmental safety. Tunnel construction is an important area of engineering and construction that requires highly qualified specialists and advanced technologies. This complex process requires taking into account geological, hydrogeological and other features of the area where the tunnel will be built.

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