(A) the underground space form

Urban underground space is a discontinuous artificial space structure, which is different from the above-ground space and needs systematic planning and long-term development to gradually form a continuous spatial form. Urban underground space forms include plane form and vertical form. The horizontal direction refers to the spatial distribution of urban underground elements, and the vertical form is the vertical extension of the plane form.

1. Plane form

According to the characteristics of urban underground space development, underground space forms can be divided into three basic forms and three derivative forms. That is to say, urban underground space forms a radial, ridge or whole network through different combinations of related points, lines and surfaces. The significance of derivative form is that it can make connected points, lines and surfaces produce functions that can not be completed by a single form.

1) Point-shaped: Compared with the overall form of urban underground space, point-shaped underground space is the basic constituent element of urban underground space form and the most elastic element, which is formed by various underground spaces occupying a small plane range in the city. Dotted underground space is distributed all over the city, generally concentrated in the city center, station square, assembly square, large public buildings, residential areas and other places where urban contradictions are concentrated. Point-shaped underground space facilities in harmony with urban ground functions play a very important role in solving the problems of pedestrian and vehicle diversion and static and dynamic traffic congestion in modern cities.

"Points" are big and small, and the big ones can be complex complexes. For example, the city subway station is the connection point with the ground space and the distribution point of people. At the same time, with the comprehensive development of subway stations and surrounding areas, a multi-functional underground complex integrating commerce, entertainment, crowd distribution and parking can be formed. Small can be a single shopping mall, underground garage, sidewalk or municipal facilities, such as underground substation or underground garbage collection station.

2) Linearity: Linear underground space is the horizontal extension or connection of point underground space relative to the overall form of urban underground space. Linear underground space facilities are the key and basic elements of urban underground space form. Linear underground space mainly refers to subways, underground roads and underground facilities built along the street, such as municipal pipelines, underground pipeline comprehensive corridors, underground flood discharge (water) culverts, underground parking garages and underground commercial streets. In addition, the connection between adjacent point underground spaces can also be a linear space.

Linear underground space facilities are the basic skeleton of urban underground space form, which connects underground scattered spaces into a system and improves the benefit of overall development. At present, most cities in China lack understanding of the role and position of linear space in the development and utilization of underground space, and fail to form an overall spatial form.

3) Area: The formation of underground space in urban areas is a sign of the maturity of urban underground space and an inevitable result of the development of urban underground space to a certain stage.

A number of large underground spaces are interconnected to form an area. This form mainly appears in urban centers and other areas with relatively strong ground development intensity, and is mainly composed of underground public spaces such as large-scale building basements, subway (transfer) stations and underground commercial streets. This form needs to be gradually formed on the basis of reasonable planning of underground space. If the connectivity reserved in the transformation of old areas is not considered in the early development, it is more difficult, but it is easier to form in the new city center.

4) Radial type: with large underground space facilities as the core, it forms a radial shape through communication with other surrounding underground spaces. This form appeared in the early stage of the development and utilization of urban underground space, that is, through the development of large-scale underground space facilities, the development and utilization of underground space in surrounding plots were promoted, and underground space facilities in some areas formed a relatively complete system. This form is mostly formed by the underground space of subway (transfer) station and central square.

5) Ridge: The linear underground space of a certain scale is taken as the axis, radiating to both sides, forming the underground space form of the ridge. This form is very common in cities without subway stations. It is mainly an underground street or underground parking garage built along the street, which is connected with the underground commercial space or parking garage under the buildings on both sides. This form is more common in Japanese cities.

6) Network: The form of reticulated underground space is relative to the overall form of urban underground space, that is, with urban underground traffic as the skeleton, the underground space of the whole city is connected in various forms to form a network system of urban underground space. The underground expressway and underground parking system in the city center being studied in Japan is also a new type of network underground space.

2. Vertical form

Vertically, the above-ground and underground space of the city should be taken as a whole, and the three-dimensional development should be carried out to the maximum depth according to the suitability of land and economy to maximize its function. The stratification of urban vertical space is closely related to people's concentration of urban vertical space position. Generally speaking, vertical position composition can be divided into the following four levels from top to bottom.

1) The surface layer (5 m below the ground) has strong publicity and can be used as an extension of the ground function, which is mainly composed of municipal facilities, pipelines and parking lots.

2) Shallow underground area (5 ~ 10 m underground), whose main functions are commerce, entertainment, parking and pedestrian traffic.

3) The middle underground area (below the ground 10 ~ 20 m) is independent and closed. Its functions are mainly subway traffic and parking garage, and it is also used for commerce.

4) The deep underground area (20 m below the ground) has strong independence and closeness, and its function is based on the deep underground traffic in the city, some special needs and the space needs of adopting special technologies.

(2) Types and characteristics of underground space

At present, the main modes of development and utilization of underground space in urban central areas in China are:

1) Comprehensive form of subway: Combined with subway construction, an underground complex integrating business, entertainment, subway transfer and other functions will be built, which will be organically combined with ground squares, bus stations and underground passages to form a multifunctional comprehensive transfer hub, such as the underground complex in Huangsha area of Guangzhou.

2) Underground passage-shopping mall type: At the intersection of urban traffic jams, an underground sidewalk system with commercial and entertainment facilities is mainly built, which not only relieves the chaotic state of ground traffic, separates people and vehicles, but also obtains considerable economic benefits. It is a model worthy of promotion, such as the underground shopping mall in the center of Jilin.

3) Independent underground shopping malls and garages-Shopping malls: for the convenience of tourists and citizens, underground shopping malls are built in places with good economic and geographical conditions such as railway stations, such as the underground complex of Shenyang Railway Station Square.

4) Comprehensive shaping of the city center: build comprehensive commercial facilities in the downtown area of the city center, integrating commerce, culture and entertainment, parking and public facilities, and gradually create conditions for the development of underground cities, such as the underground shopping mall of Shanghai People's Square, underground garage and Hong Kong Street complex.

5) Historical features and landscape protection: In historical cities, historical sites and scenic spots, in order to protect the traditional features and natural landscapes on the ground from being destroyed, underground space is often used to solve the problem satisfactorily, such as the underground square of Xi 'an Bell and Drum Tower.

6) Basement utilization type: Generally, box foundations are used in high-rise buildings, and the buried depth is large. Surrounded by soil medium, the overall stability of the building is strengthened, and the internal space of the box foundation itself provides conditions for building multi-storey basements. It is a common practice to put garages, equipment rooms and warehouses in the basement of high-rise buildings. Since the reform and opening up, more than 4 million square meters have been built.

7) Transformation: The transformation and utilization of existing underground buildings and civil air defense projects is a major aspect of underground space utilization in China in recent years, which has the characteristics of low development cost and wide development uses. The rebuilt underground buildings are often used as entertainment, shops, bicycle garages and warehouses.

Two. Utilization of underground space in Shenzhen

The use of underground space in Shenzhen, in addition to the underground outdoor of single buildings with civil defense as the main purpose, is mainly the subway and its related underground commercial streets. Therefore, this paper mainly analyzes the utilization of underground space in subway construction and planning.

1. Analytic Hierarchy Process of Shenzhen Metro Planning

According to different functions and technical standards, Shenzhen subway planning is divided into four levels: Pearl River Delta intercity line, urban group express line, urban trunk line and urban local line. The latter three constitute Shenzhen's internal subway network. Whether the former can be promoted smoothly will directly determine Shenzhen's future position in the metropolitan area.

(1) Pearl River Delta Intercity Line

Shenzhen incorporated the Pearl River Delta into subway planning for the first time, showing its determination as one of the regional central cities.

The planned Pearl River Delta Intercity Line plays a role in connecting Shenzhen with surrounding towns along the line, with long-distance cross-city travel service as the main service. When the distance between stations is more than 3km, the maximum speed is generally120 ~140 km/h. The intercity line will strengthen the connection between Shenzhen and other areas in the Pearl River Delta, strengthen Shenzhen's regional central position and radiation ability to surrounding areas, and promote the coordinated development of Shenzhen and Hong Kong.

The Pearl River Delta intercity line planned by Shenzhen includes:

1) Guangzhou-Shenzhen Intercity Line: Futian Central District → Guangzhou. Contact Shenzhen core area with Qianhai-Baoan, Fuyong, Shajing, Dongguan Chang 'an-Humen, Guancheng, Guangzhou and other places; Songgang Reserve 1 1 line extends to the northwest and connects with Dongguan section. When conditions are ripe, the line 1 1 will be used to directly connect with Futian Central District.

2) Shenzhen-Guancheng Intercity Line: Longhua Railway Station → Guancheng. Contact Longhua and Guangming in central and western Shenzhen with Songshan Lake and Guancheng in Dongguan; Line 6 is reserved to extend northward in Guangming, connecting with Dongguan regional rail express line R 1. When conditions are ripe, Line 6 will be used for direct docking with Longhua New Passenger Station.

3) Shenhui Intercity Line: Futian Central District → Huizhou. Contact Shenzhen core area, eastern cities and Huiyang, Huizhou and other places; 14 line is reserved in Kengzi to extend eastward and connect with Huizhou rail line. When the conditions are ripe, use 14 line to directly connect with Futian central area.

4) West-Shenzhen-Hong Kong Intercity Line: Before the Bay → Hong Kong. Contact the western coastal area of Shenzhen with the central area of Hong Kong and the Hong Kong airport; The 1 1 line is reserved to extend southward to Qianhai Hong Kong.

5) Shenzhen-Jiangcheng International Line: Futian Central District → Jiangmen. Contact Shenzhen core area, Longhua, Fuyong, Zhongshan, Jiangmen and other places; As the river crossing project is huge, it is considered to build it together with the west extension section of guangzhou-shenzhen railway, and make use of the surplus capacity of the south section of Longhua of Guangzhou-Shenzhen-Hong Kong Passenger Dedicated Line.

(2) Shenzhen Metro (South China Metro Center)

Shenzhen * * * has planned 6 subway lines/kloc-0, with a total length of 585.3km and 357 stations. Among them, there are 4 group express lines, 6 trunk lines, 6 local lines and 4 planned intercity lines.

After the completion of the planning, Shenzhen will form an area with Luohu in the east and Baoan Central District in the west as the core, covering Futian CBD, OCT and Nantou Peninsula. This area will become the center of the whole subway network. Once the subway is fully completed, the transformation of business and life in this area will be extremely rapid, which should be paid enough attention to.

1) Urban Group Speed: Futian Central District benefits the most. The urban group express line connects the urban core area with the peripheral groups, or contacts multiple peripheral groups, mainly providing long-distance travel services. The distance between stations is about 2 ~ 3 km, and the maximum speed is generally100 ~120 km/h. The rapid development of groups outside the special zone, especially the "four new cities", will promote the integration inside and outside the special zone and the formation of urban polycentric structure.

City Group Express includes the following lines:

6 # subway: 37.2km "Songgang → Longhua Railway Station".

1 1 # Subway: 49.7km "Futian Central District → Songgang".

13 # subway: 48. 1km "Ocean Garden → Tangkeng", provided that the prospect extends to the reserved southern salt field.

14 # subway: 50.7km "Futian Central District → Kengzi".

2) Urban trunk line: connecting the main gathering nodes of the city and their areas along the line, mainly providing short-distance travel services. The distance between stations is about 1km, and the maximum speed is generally 80 ~100 km/h. The trunk line covers the main passenger corridors of the city, which will alleviate the urban traffic pressure, promote the intensive use of land and build the main development axis of the city.

Urban trunk lines include the following lines:

1 # Subway: 44. 1km "Luohu Railway Station → Airport North".

2 # subway: 3 1.3km "Shekou → East Gate".

No.3 subway: 49.2km "Bonded Zone → Pingdi".

Subway No.4: 27.2km "Huanggang Port → Guanlan".

5 # subway: 42.4km "in front of the bay → Grand Theatre", and the conditions for the prospect to extend southward are reserved at the west end; The distance between Baoan and Buji stations is large, which can basically meet the functional requirements of the express line.

10 # subway: 42.2km "Sea World → Songgang".

3) Urban local line: It is a supplementary line of urban trunk lines and express lines, and mainly provides short-distance travel services. The distance between stations is about 1km, and the maximum speed is generally not more than 80 km/h. On the basis of the upper line, the coverage of local lines will be further increased, traffic pressure will be alleviated, and the links between various sections in the peripheral city will be strengthened.

City local telephone lines include the following lines:

7 # subway: 28.9km "Luohu Taian → Xili Zoo".

No.8 subway: 25.9km "Guo Mao → xiaomeisha".

9 # subway: 17.8km "Luohu Railway Station → Shangsha".

12 # subway: 36.4km "Sports New Town → Kengzi".

15 # subway: 24.7km "Qianhai Road → Shiyan → Tian Xin", with the condition of connecting to Line 5 in the west reserved.

16 # subway: 29.5km "Yitian Village → Pinghu → Dawang", and reserve the conditions for the prospect to extend northward and connect with 12 line via Fenggang, Dongguan; A branch line leading to the Hetao area on the Shenzhen-Hong Kong border is reserved in the south.

2. Shenzhen subway construction planning

The first phase of Shenzhen Metro was completed and opened to traffic on February 28th, 2004, and the second phase (1 #, 2 #, 3 #, 4 # and 5 # subways) has been partially started. The above two phases are scheduled to be completed and opened to traffic in June, 20 165438.

The focus of this subway planning is to put forward the track construction plan in the near future (20 1 1 ~ 2020) based on the first and second phases of the project, with a total of ***8 track lines with a total length of about 245.4km (Table 3-2- 1). /kloc-After the completion of Phase 0, Phase 2 and Phase 3 subways, the subway will become the main mode of travel for Shenzhen residents, and other streets in Shenzhen except Nan 'ao and Dapeng will be connected with the subway. The mode of transportation in Shenzhen will enter the era of pan-subway, and the scarcity of the subway will also be reduced.

Table 3-2- 1 List of Construction Lines of Shenzhen Metro Phase III

In addition, according to the Regulations of Shenzhen Municipality on Building Civil Defence Basements in Combination with Civil Buildings (1994 10128 October), the newly-built civil buildings are more than 10 (including10) or the foundation buried depth is 3m (including 3m). Urban planning determines newly built or rebuilt residential areas, communities and unified housing (including commercial housing). According to the one-time planning and design tasks, 2% of the total construction area of new buildings on the ground will be planned and constructed in a unified way. Central and local enterprises, institutions, administrative units and military units should build civil defense basements according to 2% of the total construction area, whether they are built at one time or by stages, or by themselves or jointly.

From the above analysis, it can be seen that the scale of underground space utilization in Shenzhen will increase exponentially in the next decade, regardless of whether the subway planning is an underground excavation scheme or an overhead scheme. In addition, with the construction of existing civil air defense basement, the underground engineering construction and underground excavation are great, and the transformation of geological environment is unprecedented. The geological environment protection and management of land resources, geology and mineral resources management departments has a long way to go, and it is necessary to make preparations in advance in terms of legislation, management system and staffing.