How Earthscrapers May Soon Become our Future Homes

Imagine building massive underground structures instead of towering skyscrapers. Earthscrapers could be the future of urban living. With growing populations, housing shortages, and limited space in cities like Mumbai, Delhi, and Bangalore, we need to think differently. Countries like Mexico, Japan, and Finland are already exploring underground construction, from multi-story towers to extensive tunnel networks. This isn't just about engineering; it's a shift in how we approach building and living in the 21st century.

The Housing Crisis: A Global Problem

Cities worldwide are facing a severe housing crisis. In Paris, for example, the average home costs around ₹1 lakh per square foot, with a modest 498 sq ft flat selling for ₹7.5 crore. Despite this, 26% of flats remain vacant. With a population density of 20,000 people per square kilometre, even those earning ₹2.9 lakh per month struggle to afford housing, often living in rented, smaller spaces. Many European cities, like Paris, have laws preventing the construction of tall skyscrapers to preserve historical character, making space even more valuable.

This unaffordability isn't unique to Paris. London, Barcelona, Munich, and Stockholm are also experiencing housing crises. The sheer density of some cities, like Tokyo with its 40 million inhabitants, necessitates 'professional pushers' to manage crowded metro trains. In India, Mumbai and Bangalore face similar issues. A report suggests that top earners in Mumbai would need 109 years of savings to buy a home in the main city. This has led to the development of massive slums like Dharavi, where 3.5 lakh people live within a single square kilometre.

Globally, the situation is dire. The United Nations reports that 40% of the world's population, or 2.8 billion people, are either homeless or live in substandard conditions. Projections indicate that an additional 2.5 billion people will move to cities in the next 25 years, with 70% of the global population residing in urban areas. With land being a finite resource, innovative solutions are urgently needed.

Earthscrapers: A Solution from Below

In 2009, Mexico City faced a similar challenge with its Zócalo Square, a historically significant but densely populated area. Due to regulations limiting building height to eight floors, finding space for the growing population was difficult. Esteban Suárez, founder of BNKR Arquitectura, proposed a radical solution: "If we can't go up, we go down." His concept was a 65-floor underground building, an "earthscraper," designed as an inverted pyramid.

This design addresses several key issues:

• Sunlight: A large central light well would allow sunlight to reach the lower levels.
• Usable Surface: The top, a flat glass floor, would remain open for public use, suitable for parks, gatherings, and events.
• Living and Working Spaces: Residential and commercial areas would be built into the sides of the inverted pyramid, with lobbies featuring greenery to create a more natural experience.
• Historical Preservation: The first ten floors would house museums and historical centres, preserving artefacts found during excavation and respecting the site's heritage.

Suárez envisioned that a successful earthscraper could lead to the creation of entire underground cities, efficiently connecting different hubs and alleviating traffic congestion. This concept offers a new dimension for urban expansion, potentially solving housing crises and improving city infrastructure.

Historical Precedents and Modern Examples

The idea of underground living is not entirely new. In 1963, a vast underground complex was discovered in Cappadocia, Turkey, dating back 3,200 years. This network of 200 connected cities, including the 18-floor deep Derinkuyu, housed up to 20,000 people and featured residential areas, community halls, stables, and ventilation shafts that maintained a stable temperature.

More recently, Finland has developed an extensive underground network beneath its capital, Helsinki. This 293 km system, extending up to 15 floors deep, includes roads, railways, emergency shelters, sports facilities, and even swimming pools. Initially built for protection during the Cold War, the Finnish government has expanded these underground assets, recognising their strategic advantages.

Japan, a country prone to natural disasters, has also excelled in underground engineering. Tokyo's massive underground canal system, built 50 meters below ground, diverts excess water from its 100+ rivers and canals, significantly reducing flood damage. This system, featuring giant storage tanks supported by massive pillars, demonstrates advanced engineering capabilities.

Engineering Challenges and Solutions

While the concept of earthscrapers is promising, several engineering challenges need to be addressed. Constructing a 65-floor underground building requires a "top-down" approach, unlike traditional skyscrapers built from the ground up.

Key construction steps would involve:

1. Excavation and Wall Construction: Digging a boundary trench and installing thick diaphragm walls (at least 2 meters thick) using hydraulic excavators and bentonite slurry to prevent soil collapse and manage lateral earth pressure and water pressure, especially in Mexico City's clay-rich, waterlogged soil.
2. Pillar Installation: Installing 1-2 meter thick, load-bearing piles or columns from the surface down to bedrock (300 meters) to support the structure and create the central light well.
3. Top-Down Construction: Building horizontal beams and floors from the top down, pouring reinforced concrete to solidify the skeleton and constructing rooms according to the layout.
4. Utility Installation: Adding essential utilities like staircases, elevators, fire exits, lobbies, gardens, and parks, followed by finishing touches like flooring and tiling.

Potential challenges like earthquakes, underground flooding, darkness, and fire safety have solutions. Earthscrapers, being closer to the ground, might experience less resonance during earthquakes compared to tall skyscrapers. Flexible materials and damping systems can absorb shocks. Optical fibres can transmit sunlight underground, and powerful pumps, similar to those used in Japan's flood control systems, can manage water. Fire safety can be addressed with fire-resistant materials, emergency exits, and underground water reserves.

Why the Delay?

Despite the technological feasibility, the Mexico City earthscraper project has been on hold since 2011. The primary reasons are not technical but psychological and financial. The idea is considered ahead of its time, facing resistance due to:

• Political and Cultural Concerns: Potential public opposition to building on a historically significant site and the risk of it becoming a political issue.
• Historical Preservation: The possibility of damaging priceless historical artefacts during excavation.
• Construction Delays: The risk of the project taking over a decade, causing significant disruption in the city centre.
• Financial Risk: Investors are hesitant due to the high proposed cost (initially $800 million, likely to escalate) and the uncertainty of market acceptance for underground living compared to sky-high views.
• Regulatory Hurdles: The need to rewrite safety regulations (fire, water, gas) for a completely new type of construction, leading to potential bureaucratic delays.

This situation highlights the significant resistance new ideas face, often stemming from psychological barriers rather than physical limitations. History is replete with examples of groundbreaking technologies initially dismissed as impractical, only to revolutionize society later.

Key Takeaways

• Urbanisation Drives Innovation: Growing city populations and limited land necessitate creative housing solutions.
• Underground Construction is Viable: Historical and modern examples demonstrate the feasibility of large-scale underground structures.
• Earthscrapers Offer Benefits: They can alleviate housing crises, reduce urban sprawl, and potentially mitigate traffic issues.
• Challenges are Manageable: Engineering hurdles like earthquakes, flooding, and safety can be overcome with existing and developing technologies.
• Psychological Barriers Exist: Resistance to new ideas often stems from fear of the unknown, financial risk, and regulatory complexities.
• Embrace Different Thinking: Innovation requires daring to think differently and challenging conventional approaches, much like Finland and Japan have done with their underground infrastructure.