The integrated design of urban underground Spaces (such as subway stations, commercial complexes, parking lots, etc.) with the ground environment needs to address core issues such as spatial fragmentation, functional discontinuity, ecological fragmentation, and visual oppression. Integration should be achieved through four dimensions: functional connection, visual penetration, ecological continuity, and behavioral guidance. The following elaborates on design strategies, technical means and case inspirations:

First, functional connection: vertical movement lines and horizontal networks

Vertical transportation system

Direct entrance: Reduce the height difference between the ground and underground, for example, by connecting through a gentle slope (slope ≤1:12), escalator or vertical elevator, to avoid the congestion of people caused by stepped entrances.

Multi-directional diversion: In large hubs (such as railway stations and business districts), multiple entrances are set up to disperse the flow of people. For instance, the Xizhimen subway station in Beijing is connected to the ground square, bus stop and shopping mall through a "cross" circulation line.

Elastic transition space: At the entrance, a buffer square or gray space (such as arcades or corridors) is set up, which not only ADAPTS to bad weather but also weakens the sense of enclosure of the underground space.

Horizontal network extension

Underground pedestrian street: It connects surrounding buildings through underground passages to form a "ground-underground" double-level pedestrian system. For example, Roppongi Hills in Tokyo is connected to subway stations, office buildings and shopping malls through an underground network.

Ground sign penetration: Visual guidance for the entrance of underground space is set up on the ground (such as ground projections, light signs), for example, Shenzhen Futian Metro Station uses ground light strips to indicate the direction of underground passages.

Second, visual penetration: Breaking the sense of isolation and psychological oppression

Skylights and light Wells

Natural light introduction: Natural light is introduced underground through skylights and sunken courtyards. For example, in the atrium of "Canyon of Light" at ION Orchard Mall in Singapore, the area of natural light is expanded by using glass ceilings and mirror reflections.

Light and shadow art: Dynamic light and shadow effects are designed by using light Wells. For instance, the K11 shopping center in Shanghai combines top glass with water screens to create a flowing light and shadow space.

Landscape continuation and visual extension

Vertical greening infiltration: Planting green plants on the walls of underground Spaces or introducing ground landscapes underground through glass curtain walls. For instance, the "Green Atrium" of Hong Kong IFC Mall connects the rooftop garden with the underground level through transparent glass.

Art installation guidance: Set up large-scale art installations or sculptures in underground Spaces to create visual focal points. For instance, the "Cloud Gate" sculpture at La Defense Metro Station in Paris attracts people to explore the underground space.

Third, ecological continuity: Restore the ecological fragmentation between the surface and underground

Rainwater management and ecological infiltration

Infiltration design: Permeable pavement and rain gardens are set up on the ground, and rainwater is introduced into underground water storage tanks through shafts or pipes for green irrigation or emergency drainage. For example, the Singapore Bishan Hwang Mo Kiu Park achieves rainwater recycling through an underground water storage system.

Ecological corridor connection: Plant troughs or vertical greening are set up in underground passages to form ecological continuity between the ground and underground. For example, HafenCity in Hamburg, Germany, plants shade-tolerant plants are planted in underground passages to connect the ground wetland with the underground space.

Microclimate regulation

Ventilation shafts and natural ventilation: By introducing natural air through ground ventilation shafts, the mechanical ventilation energy consumption in underground Spaces is reduced. For instance, in Tokyo Midtown, underground ventilation shafts are combined with ground greenery to create "breathing" underground Spaces.

Temperature and humidity control: By taking advantage of the constant temperature feature underground and combining it with ground greening to regulate the microclimate, for instance, the underground shopping mall of Wulin Square in Hangzhou has reduced the temperature in summer through the linkage of ground water features and underground air conditioning systems.

Fourth, behavioral guidance: Strengthen the public attribute of underground space

Extension of ground activities

The interaction between sunken plazas and the ground: By using sunken plazas to bring ground activities underground, for instance, Chengdu Taikoo Li holds markets and performances through sunken plazas, enhancing the vitality of the underground space.

Ground sign interaction: Interactive devices or information screens are set up on the ground to display the activity information of the underground space in real time. For example, Cheonggyecheon Square in Seoul uses ground projections to display the promotional information of the underground shopping mall.

Infiltration of cultural symbols

Continuation of ground cultural elements: Designing the continuation of ground cultural symbols in underground space (such as ground paving patterns and sculptures), for instance, Beijing's Wangfujing Street replicates the elements of historical buildings on the ground through underground space to enhance cultural identity.

Thematic scene creation: Based on the ground functions, the theme of the underground space (such as business, art, and technology) is positioned. For instance, the 1862 Fashion Art Center in Shanghai forms a cultural connection with the ground theater through the underground art exhibition hall.

Fifth, Comparison and implications of Typical cases

Success case

ION Orchard Mall in Singapore: Through the vertical infiltration of the "Canyon of Light" atrium and the rooftop garden, it breaks the closed feeling of the underground space and becomes a city landmark.

Roppongi Hills in Tokyo: By connecting the surrounding buildings through an underground pedestrian network, a "ground-underground" two-tier city is formed, enhancing the utilization rate of space.

Failure case

The underground commercial street in a certain city: The entrance is concealed and the lighting is insufficient, resulting in the underground space becoming an "underground warehouse", lacking public attributes.

The design of the exit of a certain subway station: There are too many steps and no shading facilities. The high temperature in summer causes pedestrians to have to walk around the ground, resulting in a low utilization rate of underground space.

Core conclusion

The integrated design of underground space and surface environment should aim at "functional integration, visual transparency, ecological continuity, and behavioral guidance". Through means such as vertical transportation, the introduction of natural light, ecological corridors, and the infiltration of cultural symbols, underground space should be transformed into an organic extension of urban public life. During the design process, problems such as excessive closure, single function and ecological fragmentation should be avoided, and a balance between short-term experience and long-term sustainability should be emphasized.